2022 microbiology columns - Healthcare Hygiene magazine

‘Tis the Respiratory Season

By Rodney E. Rohde, PhD, MS, SM(ASCP) CMSV CM, MBCM, FACSc

This article originally appeared in the December 2022 issue of Healthcare Hygiene magazine.

As the holiday season arrives, most of us are busy planning for family visits, traveling, and having time together with loved ones and friends. It is especially exciting for much of the world as we watch and hope that perhaps the difficult times of an ongoing three-year pandemic are maybe calming. However, we must remain diligent with our preventative measures this year because we are seeing an alarming rise in several respiratory microbial agents, including influenza, parainfluenza, enteroviruses COVID-19, and RSV.

Currently, many hospitals in the United States and globally are reporting surges in RSV which are overwhelming bed availability. Respiratory syncytial virus (RSV) is a common respiratory virus that usually causes mild, cold-like symptoms. Most people recover in a week or two, but RSV can be serious, especially for infants and older adults. RSV is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia (infection of the lungs) in children younger than 1 year of age in the U.S.

How is RSV transmitted?
RSV can be spread when
• An infected person coughs or sneezes and respiratory droplets enter your eyes, nose or mouth
• You have direct contact with the virus, like kissing the face of a child with RSV
• You touch a surface that has the virus on it, like a doorknob or other high touch surface (phone, computer keys, etc.), and then touch your face before washing your hands.

One is typically contagious with RSV for three to eight days and may become contagious a day or two before they start showing signs of illness. However, some infants, and people with weakened immune systems, can continue to spread the virus even after they stop showing symptoms, for as long as four weeks. Young people are often exposed to and infected with RSV in schools, daycare or childcare centers.

As I have written many times in my article, all surfaces matter in the transmission of pathogens. RSV can survive for many hours on hard surfaces [counter tops, door handles, etc.) while it usually lives on soft surfaces such as tissues, hands, and cloth for shorter amounts of time.

RSV infections occur most often first with infants or toddler and nearly all children are infected before their second birthday. However, all ages can be infected throughout their life. Infections in healthy children and adults are generally less severe than among infants and older adults with certain medical conditions. In the U.S and other areas with similar climates, RSV circulation generally starts during fall and peaks in the winter. Seasonality and severity of RSV moving through a particular geographic area and any community is variable annually.

Who is most at risk for severe RSV?
Individuals who are more likely to experience severe complications from infections with RSV include
• Premature infants
• Young children with congenital (from birth) heart or chronic lung disease
• Young children with compromised (weakened) immune systems due to a medical condition or medical treatment
• Children with neuromuscular disorders
• Adults with compromised immune systems
• Older adults, especially those with underlying heart or lung disease

How can one prevent the spread of RSV?
As with most respiratory pathogens, there are some simple and effective ways to prevent the spread of RSV. Some of the more common measures include
• Cover your coughs and sneezes with a tissue or your upper shirt sleeve, not your hands
• Handwashing (often) with soap and water for at least 20 seconds
• Avoid close contact, such as kissing, shaking hands, and sharing cups and eating utensils, with others
• Clean frequently touched surfaces such as doorknobs and mobile devices
• Limit the time one spends in childcare centers or other potentially contagious settings during periods of high RSV activity. This may help prevent infection and spread of the virus during the RSV season
• Avoid close contact with sick people

Currently, there are no RSV vaccines, but research is moving forward to develop one. Moderna is working on a trivalent vaccine for influenza, RSV and COVID-19. Pfizer also recently announced positive top-line data of Phase 3 Global Maternal Immunization Trial for its bivalent RSV vaccine candidate.

There is a drug called palivizumab utilized for preventing severe RSV illness those at high-risk for infection, including premature infants or infants with congenital (present from birth) heart disease or chronic lung disease. Palivizumab may prevent serious RSV disease, but it cannot help cure or treat children or prevent infection with RSV.

Current outlook for RSV
U.S. RSV cases started showing up in the spring and are now 60 percent higher than 2021’s peak week according to data obtained via the Centers for Disease Control and Prevention (CDC). I, and many other experts, have discussed how the COVID-19 pandemic preventative measures (physical distancing, masking, quarantine, or isolation, etc.) likely created an immunity gap in society. While that was critical to help with reducing mortality and severe COVID-19 outcomes, it also prevented our exposure to other agents like RSV, rhinoviruses, adenoviruses, influenza, enteroviruses, and others. We knew this would likely occur and now we need to be prepared to deal with it via testing, prevention, and watching those most at risk for possible healthcare interventions. Eventually, we will get back to what may be considered normal levels and normal seasonality of pathogens. ‘Tis the [respiratory] season! Be safe and be aware of your health and behaviors.

For more information, see: https://www.cdc.gov/rsv/index.html

Rodney E. Rohde, PhD, MS, SM(ASCP)CM SVCM, MBCM, FACSc, serves as chair and professor of the Clinical Laboratory Science Program at Texas State University. Follow him on Twitter @RodneyRohde / @TXST_CLS, or on his website: http://rodneyerohde.wp.txstate.edu/

Monkeypox: Now What?

By Rodney E. Rohde, PhD, MS, SM(ASCP) CMSV CM, MBCM, FACSc

This article originally appeared in the October 2022 issue of Healthcare Hygiene magazine.

On May 7, 2022, the world was alerted to a confirmed case of monkeypox in the United Kingdom. Cases have since occurred globally, from Germany and Spain to the U.S. and Canada. The global outbreak has expanded to almost 50,000 cases in over 99 locations with 92 locations from non-endemic areas. The U.S. has now exceeded 20,000 cases in all 50 states and territories. Currently, there have been 12 deaths globally but none in the U.S.

Endemic to Central and West Africa, monkeypox was first discovered in 1958 in monkeys kept for research in the Democratic Republic of the Congo (DRC). The first human case was not reported until 1970 in the DRC. Cases have appeared since that time throughout Africa and beyond, including Singapore, the U.K, Israel and the U.S. Most infections occur in people who live, have travelled to, or have been in contact with individuals or animals from endemic regions. For example, in 2003 more than 70 people in the U.S. fell ill with monkeypox after handling prairie dogs that were co-housed with infected Gambian pouched rats and dormice imported from Ghana. However, infections don’t always follow this transmission pattern, as evidenced by the current spread of monkeypox among people who have not travelled to endemic countries or been in contact with those known to be infected with monkeypox.

In the current 2022 outbreak, the primary transmission route has been concentrated in men who have sex with men (MSM). To date, it is unclear, and remains under investigation, whether monkeypox can be transmitted specifically through sexual transmission routes. Clearly, monkeypox is transmitted by close contact via skin to skin or by contact of skin with fomites (linen, clothing, etc.). Respiratory transmission is possible, but it is not an effective or efficient vehicle for spread of the virus.

In its August 26, 2022, Morbidity and Mortality Weekly Report, the Centers for Disease Control and Prevention (CDC) reported the High-Contact Object and Surface Contamination in a Household of Persons with Monkeypox Virus Infection — Utah, June 2022. The two persons with monkeypox were confirmed positive by real-time polymerase chain reaction (PCR) and lived together without other housemates. Both persons experienced prodromal symptoms (e.g., fatigue and body aches). Eight days of symptoms, patient A experienced penile lesions; lesions spread to the lips, hands, legs, chest, and scalp by day 10. Patient B experienced prodromal symptoms eight days after illness onset of patient A; patient B experienced a lesion on the foot which spread to the leg and finger by day 11. Although both patients had lesions in multiple anatomic areas, the overall number of lesions was small, and lesions varied in presentation from “pimple-like” or ulcerated, to characteristically well-circumscribed and centrally umbilicated. Both patients had mild illness. The time from symptom onset to resolution was approximately 30 days for patient A and approximately 22 days for patient B.

The Utah Department of Health and Human Services (UDHHS) assessed the presence and degree of surface contamination of household objects contacted by monkeypox patients by swabbing objects in the home of the patients. The patients identified high-contact objects and surfaces for sampling; the patients also described “normal types” of cleaning and disinfection activities performed within the home during their illness and locations within the home where they spent substantial amounts of time while ill. The patients had isolated at home for 20 days before their home was entered for sampling. The patients were still symptomatic at the time UDHHS collected specimens from their home. The temperature in the two-story home ranged from 69 degrees F (20.6 degrees C) to 75 degrees F (23.9 degrees C) during isolation.

Specimens were obtained from 30 objects in the home and tested for both non-variola Orthopoxvirus and West African Monkeypox virus–specific real-time PCR assays. Viral culture was only pursued if the qualitative PCR result was positive. This activity was reviewed by the CDC and was conducted consistent with applicable federal law and CDC policy. Among the 30 specimens, 21 (70 percent) yielded positive real-time PCR results, including those from all three porous items, 17 of 25 (68 percent) nonporous surfaces and one of two mixed surface types.

Both patients reported showering and using hand hygiene regularly while also doing the laundry (including bedding, etc.) weekly and cleaning most high contact surfaces “often” during their illness. However, the cleaning spray used was not listed on the Environmental Protection Agency’s List of Disinfectants for Emerging Viral Pathogens.

Monkeypox virus DNA was detected from many objects and surfaces indicating that some level of contamination occurred in the household environment. However, by not detecting viable virus suggests that virus viability might have decayed over time or through chemical or environmental inactivation. Although both patients were symptomatic and isolated in their home for more than three weeks, their cleaning and disinfection practices during this period might have limited the level of household contamination. These data are limited, and additional studies are needed to assess the presence and degree of surface contamination and investigate the potential for indirect transmission of monkeypox virus in household environments. Persons living in or visiting the home of someone with monkeypox should follow appropriate precautions against indirect exposure and transmission by wearing a well-fitting mask, avoiding touching possibly contaminated surfaces, maintaining appropriate hand hygiene, avoiding sharing eating utensils, clothing, bedding, or towels, and following home disinfection recommendations.

For more information, see: https://www.cdc.gov/mmwr/volumes/71/wr/mm7134e1.htm?s_cid=mm7134e1_w

Predators Within the Microbial Jungle: The Deadly Rise of Drug-Resistant Bacteria

By Paul J. Pearce, PhD

This article originally appeared in the September 2022 issue of Healthcare Hygiene magazine.

Discovery of antimicrobials in the past century represented one of the most important advances in public health. Unfortunately, the massive use of these compounds in medicine and many other human activities has promoted the selection of pathogens that are resistant to one or several antibiotics. The current antibiotic crisis is creating an urgent need for research into new biological weapons with the ability to kill these superbugs.

A year ago, Frank Wills had taken his good health for granted. Forty years old, lean and fit, he was a recently divorced accountant living with his mother while he tried to put his life together again. Wills had been feeling weak and tired when he went to his doctor for a checkup. He told his doctor he’d been having stomach pains and chronic colds. A routine blood test revealed that he was suffering from leukemia. Although Wills was shocked and frightened by his cancer diagnosis, his doctor explained that most forms of leukemia responded well to chemotherapy. Most probably, Wills would be able to undergo the chemotherapy regimen and soon resume a normal life.

That was the beginning of the end. Wills’ oncologist initiated chemotherapy almost immediately. While often effective against leukemia and other cancers, the drastic treatment – with its toxic chemicals that course through the body like drain cleaner – can have the undesired effect of suppressing the immune system as well, frequently leading to bacterial infections that the weakened immune system cannot control. Antibiotics are used to help eradicate potentially life-threatening infections. Sometimes these bugs prove to be resistant to the initial antibiotic, in which case the doctor simply switches to another one. But for Wills, the antibiotic reserve had been exhausted.

Wills’ infection was caused by the bacterium known as Enterococcus faecium, a Gram-positive coccus that is routinely found in the patient’s intestinal tract.

One expert calls E. faecium the cockroach of microbial pathogens: proliferating freely in the intestinal tract, it usually causes no more trouble than roaches colonizing a cupboard. But when breakdowns in the immune system allow the bugs to escape, they begin to cause serious infections, anywhere from the heart down to the urinary tract. After proving resistance to the initial antibiotics used, Wills’ Enterococcus faecium also showed resistance to vancomycin, an older but still powerful antibiotic that represented the last-chance treatment for resistant enterococci when all else failed. This time vancomycin also failed; vancomycin-resistant Enterococcus faecium had appeared in Wills’ bloodstream, a dangerous escalation.

Wills recovered from the VRE infection, and his leukemia went into remission. He slowly regained his strength and was able to return to his normal life for a year. After that year his leukemia returned, as did his Enterococcus faecalis. Chemotherapy was once again discontinued, and with rest and supportive care, Wills’ better health returned – for another nine months. The bug that had been Wills’ companion once again infected his bloodstream. Back came the high fever, the chills and irregular heartbeat, the shortness of breath. But this time there was no rebound, even when the chemotherapy was halted. Wills began vomiting, and his blood pressure plunged. As the flow of blood to his brain slowed to a trickle, his vision dimmed, and he became disoriented. At the same time, his ever-weakening heart pumped less and less blood to his other vital organs. One by one they began shutting down, like lights in neighbors during power blackouts. As the kidneys and liver stopped working and cleansing his body of waste material, Wills, in effect, poisoned himself. Finally came full blown septic shock. Wills went pale and delirious, cold and clammy to the touch. He suffered a series of small heart attacks and began to suffocate as his lungs filled with fluid. Ten days after VRE infected his bloodstream a final time, Wills died at the age of 43.

For the past several years, a grim new era of multidrug-resistant bacteria is unfolding in the global healthcare system, making Wills’ case seem all too typical. Unchecked, these newly hardy, virulent, and invisible bugs are proliferating all around us, some festering on bedrails and seat cushions, telephones, thermometers and computers. Others passing through the air from one human host to the next. Silently, they colonize even the healthiest of us, coating our skin, invading our noses, spreading to our throats, swimming through our stomachs and gastrointestinal tracts – until it can now be said that any of us is ever without at least some highly drug-resistant bugs, waiting for the chance to infect those among us who grew suddenly weak and sick.

These predators within the microbial jungle are everywhere, rapidly multiplying. And with each passing year, fewer drugs are available to stop them.

Paul J. Pearce, PhD, is principal of The Pearce Foundation for Scientific Endeavor.

References:
Pearce PJ. 2002. Personal communication. 2002.

Shnayerson M and Plotkin M. 2002. The Killers Within – The Deadly Rise of Drug Resistant Bacteria.

Teamwork Makes the Dream Work – Fighting HAIs and AMR

By Rodney E. Rohde, PhD, MS, SM(ASCP) CMSV CM,MBCM, FACSc

This article originally appeared in the August 2022 issue of Healthcare Hygiene magazine.

The Centers for Disease Control and Prevention (CDC) have often stated that approximately 1 in 25 patients hospitalized in a U.S. acute care hospital has at least one healthcare–associated infection (HAI), adding up to over 700,000 infections annually. Urinary tract infections, ventilator associated pneumonia and surgical-site infection are some of the most common infection types, with as the most common pathogen. Methicillin-resistant Staphylococcus aureus (MRSA), Clostridioides difficile, and Vancomycin-resistant Enterococci (VRE) are just some of the antimicrobial resistant microbes (AMR) that are globally becoming more common every year. The COVID-19 pandemic has also exacerbated the problem due to the need to focus on stopping the SARS-CoV-2 virus, sometimes with empirical antibiotic treatment.

The World Health Organization has stated that by 2050, antibiotic resistance and HAIs will have a global economic impact of up to $100 trillion USD and 10 million deaths. If this prediction comes true, that will be one new antibiotic resistant infection every three seconds and it will exceed cancer mortality. Infection control and prevention, diagnostics, and antimicrobial stewardship are identified as key measures that can address this global problem. This article will discuss how a healthcare team approach – especially between pharmacy, infection prevention, and the medical laboratory professional – may be considered the Super Stewards of antibiotic stewardship.

Most people likely assume that a physician in the critical agent in the war on AMR and HAIs. While physicians certainly play a large role, there are many other health care, public health and medical professionals involved in this war. The primary soldiers in this battle include pharmacists, medical laboratory professionals, infection preventionists, environmental services, and nurses. Certainly, there are others, but I would argue that these professionals along with physicians create the most important team in the fight.

Infectious diseases pharmacists are frequently the lead person within health care systems in the management of antimicrobial stewardship programs and these pharmacists have emerged in the last decade as major leaders in this regard. In optimizing systems, it is apparent that interaction with medical laboratory personnel is required to enhance existing services and provide timely, accurate and easily understandable information to medical providers. While pharmacists get little (if any) education on the happenings of the medical laboratory during school, it turns out many of us need medical laboratory help to do the best job possible.

According to the Association for Professionals in Infection Control and Epidemiology (APIC), infection preventionists (IPs) are professionals who make sure healthcare workers and patients are doing all the things they should to prevent infections. Most IPs are nurses, epidemiologists, public health professionals, microbiologists, doctors, or other health professionals who work to prevent germs from spreading within healthcare facilities. They look for patterns of infection within the facility; observe practices; educate healthcare teams; advise hospital leaders and other professionals; compile infection data; develop policies and procedures; and coordinate with local and national public health agencies. An APIC credentialed IP will become “Certified in Infection Control (CIC) along with their other degrees and credentials.

The term environmental services (EVS for short) refers to a group of professionally trained cleaning staff who help to prevent the spread of infectious disease within a hospital. EVS technicians work alongside clinical staff to create a clean environment for patients while they are being treated. In other words, they are truly the front-line defender at preventing pathogens from inhabiting or colonizing your health care or community environment. These certified professionals are truly a secret weapon in the war on pathogen transmission and surface control.

Medical laboratory testing is the most critical component to a patient’s medical outcome, including the diagnosis of an antibiotic resistant infection. In fact, I preach to my students, colleagues, and anyone in healthcare or the public that there are two things I want them to remember if they believe they have an infection. First, ask (or demand) that your physician order a diagnostic confirmatory laboratory test to identify your infection before they prescribe you an antibiotic, whenever possible. In most cases, no one (not even your physician) can tell you with certainty that you have a bacterial infection without a confirmatory laboratory test. You may have a viral illness, an allergy, or some other type of immune reaction that is NOT being caused by a bacterium. If you do not have a bacterial infection, an antibiotic is wrong for you. Second, IF you do have a bacterial infection, then be sure the provider orders an antibiotic susceptibility test when possible. This complex laboratory test will determine the susceptibility profile for the bacteria. It is JUST AS IMPORTANT as finding out you have a bacterial infection because it will let the physician and pharmacist know exactly which antibiotic(s) to use. Without this information, we are all just driving the issue of antibiotic resistance and superbug creation via “survival of the fittest!” These are two medical laboratory tests you must demand!

These credentialed medical laboratory professionals form the backbone of health care and the public health system. They conduct some 13 billion laboratory medicine tests annually in the U.S. Currently, these individuals have also performed more than 1 million COVID-19 tests and counting during the pandemic. Why should anyone care? Laboratory testing is the single highest-volume medical activity affecting Americans, and it drives about two-thirds of all medical decisions made by doctors and other health care professionals from cradle to grave. Simply put, every time you enter a hospital or health care facility for care, your life is in the hands of a medical laboratory professional.

Each of these professionals are now integral parts of an effective antibiotic and antimicrobial stewardship team effort to reduce HAIs and AMR pathogens. Physicians and nurses will always be in the public view regarding patient care, but it is truly a team effort when it comes to prevention, diagnosis, treatment, and therapeutic measures.

For more information, see: https://www.cdc.gov/drugresistance/intl-activities/amr-challenge.html

The Fundamentals of Clinical Microbiology: A History of Clinical Bacteriology

By Paul J. Pearce, PhD

This article originally appeared in the July 2022 issue of Healthcare Hygiene magazine.

This is the first in a series of articles designed to inform healthcare workers about important topics related to clinical microbiology (bacteria, fungi, viruses, parasites, and prions) and the impact they may have on patient care.

Bacteria are single-celled microorganisms that lack a nuclear membrane, are metabolically active and divide by binary fission. Medically they are a major cause of disease. Superficially, bacteria appear to be relatively simple forms of life; in fact, they are sophisticated and highly adaptable. Many bacteria multiply at rapid rates, and different species can utilize an enormous variety of hydrocarbon substrates, including phenol, rubber, and petroleum. These organisms exist widely in both parasitic and free-living forms. Because they are ubiquitous and have a remarkable capacity to adapt to changing environments by selection of spontaneous mutants, the importance of bacteria in every field of medicine cannot be overstated.

The discipline of bacteriology evolved from the need of physicians to test and apply the germ theory of disease and from economic concerns relating to the spoilage of foods and wine. The initial advances in pathogenic bacteriology were derived from the identification and characterization of bacteria associated with specific diseases. During this period, great emphasis was placed on applying Koch's postulates to test proposed cause-and-effect relationships between bacteria and specific diseases. Today, most bacterial diseases of humans and their etiologic agents have been identified, although important variants continue to evolve and sometimes emerge, e.g., Legionnaire's Disease, tuberculosis and toxic shock syndrome.

Major advances in bacteriology over the last century resulted in the development of many effective vaccines (e.g., pneumococcal polysaccharide vaccine, diphtheria toxoid, and tetanus toxoid) as well as of other vaccines (e.g., cholera, typhoid, and plague vaccines) that are less effective or have side effects. Another major advance was the discovery of antibiotics. These antimicrobial substances have not eradicated bacterial diseases, but they are powerful therapeutic tools. Their efficacy is reduced by the emergence of antibiotic resistant bacteria (now an important medical management problem) In reality, improvements in sanitation and water purification have a greater effect on the incidence of bacterial infections in a community than does the availability of antibiotics or bacterial vaccines. Nevertheless, many and serious bacterial diseases remain.

Most diseases now known to have a bacteriologic etiology have been recognized for hundreds of years. Some were described as contagious in the writings of the ancient Chinese, centuries prior to the first descriptions of bacteria by Anton van Leeuwenhoek in 1677. There remain a few diseases (such as chronic ulcerative colitis) that are thought by some investigators to be caused by bacteria but for which no pathogen has been identified. Occasionally, a previously unrecognized diseases is associated with a new group of bacteria. An example is Legionnaire's disease, an acute respiratory infection caused by the previously unrecognized genus, Legionella. Also, a newly recognized pathogen, Helicobacter, plays an important role in peptic disease. Another important example, in understanding the etiologies of venereal diseases, was the association of at least 50 percent of the cases of urethritis in male patients with Ureaplasma urealyticum or Chlamydia trachomatis.

Recombinant bacteria produced by genetic engineering are enormously useful in bacteriologic research and are being employed to manufacture scarce biomolecules (e.g. interferons) needed for research and patient care. The antibiotic resistance genes, while a problem to the physician, paradoxically are indispensable markers in performing genetic engineering. Genetic probes and the polymerase chain reaction (PCR) are useful in the rapid identification of microbial pathogens in patient specimens. Genetic manipulation of pathogenic bacteria continues to be indispensable in defining virulence mechanisms. As more protective protein antigens are identified, cloned, and sequenced, recombinant bacterial vaccines will be constructed that should be much better than the ones presently available. In this regard, a recombinant-based and safer pertussis vaccine is already available in some European countries. Also, direct DNA vaccines hold considerable promise.

In developed countries, 90 percent of documented infections in hospitalized patients are caused by bacteria. These cases probably reflect only a small percentage of the actual number of bacterial infections occurring in the general population, and usually represent the most severe cases. In developing countries, a variety of bacterial infections often exert a devastating effect on the health of the inhabitants. Malnutrition, parasitic infections, and poor sanitation are a few of the factors contributing to the increased susceptibility of these individuals to bacterial pathogens. The World Health Organization has estimated that each year 3 million people die of tuberculosis, 500,000 die of pertussis, and 25,000 die of typhoid. Diarrheal diseases, many of which are bacterial, are the second leading cause of death in the world (after cardiovascular diseases), killing 5 million people annually.

Many bacterial diseases can be viewed as a failure of the bacterium to adapt, since a well-adapted parasite ideally thrives in its host without causing significant damage. Relatively nonvirulent (i.e., well-adapted) microorganisms can cause disease under special conditions - for example, if they are present in unusually large numbers, if the host's defenses are impaired, (e.g., AIDS and chemotherapy) or if anaerobic conditions exist. Pathogenic bacteria constitute only a small proportion of bacterial species; many nonpathogenic bacteria are beneficial to humans (i.e., intestinal flora produce vitamin K) and participate in essential processes such as nitrogen fixation, waste breakdown, food production, drug preparation, and environmental bioremediation. This textbook emphasizes bacteria that have direct medical relevance.

In recent years, medical scientists have concentrated on the study of pathogenic mechanisms and host defenses. Understanding host-parasite relationships involving specific pathogens requires familiarity with the fundamental characteristics of the bacterium, the host, and their interactions. Therefore, this section first presents with the basic concepts of the immune response, bacterial structure, taxonomy, metabolism, and genetics. Subsequent chapters emphasize normal relationships among bacteria on external surfaces; mechanisms by which microorganisms damage the host; host defense mechanisms; source and distribution of pathogens (epidemiology); principles of diagnosis; and mechanisms of action of antimicrobial drugs. These chapters provide the basis for the next chapters devoted to specific bacterial pathogens and the diseases they cause. The bacteria in these chapters are grouped on the basis of physical, chemical, and biologic characteristics. These similarities do not necessarily indicate that their diseases are similar; widely divergent diseases may be caused by bacteria in the same group.

Paul J. Pearce, PhD, is principal of The Pearce Foundation for Scientific Endeavor.

References:

Baron S, editor. Medical Microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston; 1996. Introduction to Bacteriology. Available from: https://www.ncbi.nlm.nih.gov/books/NBK8120/

Pearce, P. Public Health Bacteriology Laboratory Manual. Wichita Falls/ Wichita County Health Department. Wichita Falls, TX. 1970.

Investigating the U.S. Case of Human Avian Influenza A(H5) Virus

By Rodney E. Rohde, PhD, MS, SM(ASCP) CMSV CM,MBCM, FACSc

This column originally appeared in the June 2022 issue of Healthcare Hygiene magazine.

Viral respiratory agents are at the forefront of concern to healthcare and public health. As the SARS-CoV2 pandemic continues, efforts to detect and respond to index cases of ongoing and novel microbial agents is critical in our efforts to curtail outbreaks.

In an April 28, 2022 Centers for Disease Control and Prevention (CDC) news release, it was reported that a person tested positive for avian influenza A(H5) virus (H5 bird flu) in the U.S., as reported by Colorado and confirmed by CDC. The individual was involved in a direct exposure to poultry via depopulation (culling) of poultry with presumptive H5N1 bird flu. The case patient presented fatigue as their sole symptom and has recovered. Out of precaution, the patient was isolated and treated for influenza with oseltamivir (antiviral drug). Surface contamination of the nasal nares/membranes is possible in the detection of H5 bird flu in this case; however, it can’t be determined so the positive test result meets the H5 case criteria. The CDC must assume this case in an infection and take necessary actions to contain and treat.

The CDC reported that this case does not change the low human risk assessment for the general public. However, people who have job-related or recreational exposures to infected birds are at higher risk of infection should take appropriate precautions outlined in CDC guidance.

As part of our nationals (and global) efforts to understand the circulation and introduction viral (and other) agents, the CDC monitors surveillance data. Since late 2021 and into 2022, the CDC has been monitoring illness detection for anyone who may have been exposed to H5N1 virus-infected birds. As of the writing of this column, H5N1 viruses have been reported in 29 U.S. states of commercial and backyard birds, as well as in wild birds in 34 states. With more than 2,500 people having been exposed to H5N1 virus-infected birds, this is the only case detected to date. Others in the Colorado culling operation have tested negative but are being retested out of caution.

The first case was in the United Kingdom which occurred in December 2021. In that international case, the person had no symptoms and raised birds that became infected with H5N1 virus. The U.S. case in Colorado is the second human case associated with this specific group of H5 viruses that are currently predominant, and the first case in the United States. Since 2003, more than 880 human infections with earlier H5N1 viruses have been reported globally, however, the predominant H5N1 viruses now circulating among birds globally are different from earlier H5N1 viruses.

The CDC has published “Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2021-2022 Influenza Season.” This report updates the 2020-21 recommendations of the Advisory Committee on Immunization Practices (ACIP) regarding the use of seasonal influenza vaccines in the United States (MMWR Recomm Rep 2020;69[No. RR-8]). Routine annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. For each recipient, a licensed and age-appropriate vaccine should be used. ACIP makes no preferential recommendation for a specific vaccine when more than one licensed, recommended, and age-appropriate vaccine is available. During the 2021-22 influenza season, the following types of vaccines are expected to be available: inactivated influenza vaccines (IIV4s), recombinant influenza vaccine (RIV4), and live attenuated influenza vaccine (LAIV4).

In the November 2020 issue of this publication, I asked the question “Why is it so important to receive the flu vaccine during the ongoing pandemic?” The answer remains the same! Global efforts to lower the transmission of SARS-CoV2 which is responsible for the COVID-19 illness, such as reduced travel, staying home, telecommuting for work and online education, have led to a reduction in the number of people taking advantage of routine physician visits for a number of services, including getting one’s vaccines up to date. Overall, healthcare is already under dangerous workloads and shortages in both healthcare professionals and healthcare PPE, as well as other essential medical items due to the pandemic. It is vital that everyone get their routine vaccinations during the COVID-19 pandemic to protect people and communities from vaccine-preventable diseases and outbreaks, including flu.

We can never perfectly predict how bad an upcoming flu season will be for a particular year. It is always critical to prepare for the upcoming flu season since we know that it can lead to high morbidity and mortality for certain populations. It will be even more important this year to reduce flu because it can help reduce the overall impact of respiratory illnesses on the population and thus lessen the resulting burden on the healthcare system during the COVID-19 pandemic. A flu vaccine may also provide several individual health benefits, including preventing one from getting flu, lowering the severity of a flu illness and reducing one’s chances of having to go to the hospital.

For a full report of the first reported case of Human Avian Influenza A(H5) Virus, see: https://www.cdc.gov/mmwr/volumes/70/rr/rr7005a1.htm

A Fundamental Consideration for Effective Healthcare Hygiene – Microbial Pathogenicity

By Paul J. Pearce, PhD

This column originally appeared in the May 2022 issue of Healthcare Hygiene magazine.

Although there have been no studies which definitively link the transmission of an active infectious organism from the environment to a patient, there are numerous references that the environment is a contributor to healthcare-associated infections (HAIs).

How does the environment contribute to microbial transmission? This is not definitely known. However, research findings have shown that a patient admitted to a room previously occupied by a methicillin-resistant Staphylococcus aureus (MRSA) – positive or a vancomycin-resistant Enterococci (VRE) are at a significantly increased risk of acquiring MRSA and VRE. Similar findings have been reported for patients occupying a room previously occupied by a patient with Clostridioides difficile.

How do microorganisms induce disease after a patient comes in contact with a pathogenic or potentially pathogenic microorganism?

Microbial Pathogenicity

Pathogenicity is the capacity of a microorganism to initiate disease. It requires the attributes of (1) transmissibility or communicability from one host or reservoir to a fresh host, (2) survival in the new host, (3) infectivity or the ability to breach the new host’s defenses, and (4) virulence, a variable that is multifactorial and defines the ability of a pathogen to harm the host. Virulence in the clinical sense is a manifestation of a complex bacterial–host relationship in which the capacity of the organism to cause disease is considered in relation to the resistance of the host.

Types of Bacterial Pathogens

Microbial pathogens can be classified into two broad groups, primary and opportunistic pathogens. Primary pathogens can establish infection and causing disease in previously healthy people with intact immunological defenses. However, these bacteria may more readily cause disease in people with impaired defenses. Opportunistic pathogens rarely cause disease in people with intact immunological and anatomical defenses. Only when such defenses are impaired or compromised, because of congenital or acquired disease or using immunosuppressive therapy or surgical techniques, are these bacteria able to cause disease. Many opportunistic pathogens, such as coagulase negative staphylococci and Escherichia coli, are part of the normal human flora and are carried on the skin or mucosal surfaces where they cause no harm and may have beneficial effects, by preventing colonization by other potential pathogens. However, introduction of these organisms into anatomical sites in which they are not normally found, or removal of competing bacteria using broad-spectrum antibiotics, may allow their localized multiplication and subsequent development of disease. The above classification is applicable to most pathogens; however, there are exceptions and variations within both categories of bacterial pathogens. Different strains of any individual bacterial species can vary in their genetic makeup and virulence. For example, the majority of Neisseria meningitidis strains are harmless commensal bacteria and considered opportunistic pathogens, however, some hypervirulent clones of the organism can cause disease in a previously healthy individual. Conversely, people vary in their genetic make-up and susceptibility to invading bacteria. For example, Mycobacterium tuberculosis is a primary pathogen but does not cause disease in every host it invades.

Steps in the Pathogenic Process (Pathogenesis)

The process of pathogenesis involves various steps beginning with the transmission of the infectious agent to the host, followed by colonization of a patient’s body (e.g., skin, blood, urine). After the colonization of the patient, the bacteria remain adherent at the site of colonization followed by invasion of the patient’s system(s). After invasion and surviving the patient’s immune system it is ready to cause the disease.

Steps involved in the pathogenesis of the bacteria include:

Transmission
Colonization
Adhesion
Invasion
Transmission: Potential pathogens may enter the body by various routes, including the respiratory, gastrointestinal, urinary or genital tracts. Alternatively, they may directly enter tissues through insect bites or by accidental or surgical trauma to the skin. Many opportunistic pathogens are carried as part of the normal human flora, and this acts as a ready source of infection in the compromised host (e.g., in cases of AIDS or when the skin barrier is breached). For many primary pathogens, however, transmission to a new host and establishment of infection are more complex processes.

Colonization: The establishment of a stable population of bacteria on the host’s skin or mucous membranes is called colonization. For many pathogenic bacteria, the initial interaction with host tissues occurs at a mucosal surface and colonization normally requires adhesion to the mucosal cell surface. This allows the establishment of a focus of infection that may remain localized or may subsequently spread to other tissues.

Adhesion: Adhesion is necessary to avoid innate host defense mechanisms such as peristalsis in the gut and the flushing action of mucus, saliva and urine, which remove non-adherent bacteria. For bacteria, adhesion is an essential preliminary to colonization and then penetration through tissues. Successful colonization also requires that bacteria acquire essential nutrients for growth. Many bacteria express pili (or fimbriae) which are involved in mediating attachment to mammalian cell surfaces. Different strains or species of bacteria produce different types of pili which can be identified based on antigenic composition, morphology and receptor specificity.

Invasion: Invasion is penetration of host cells and tissues (beyond the skin and mucous surfaces), and is mediated by a complex array of molecules, often described as “invasins.” These can be in the form of bacterial surface or secreted proteins which target host cell molecules (receptors). Once attached to a mucosal surface, some bacteria, e.g., Corynebacterium diphtheriae or Clostridioides tetani, exert their pathogenic effects without penetrating the tissues of the host. These produce biologically active molecules such as toxins, which mediate tissue damage at local or distant sites.

Paul J. Pearce, PhD, leads The Pearce Foundation for Scientific Endeavor.

References:

Manual of Environmental Microbiology, Fourth Edition. 2016. American Society for Microbiology.

Healthcare Environmental Cleaning. Second Edition. 2012. Association for the Healthcare Environment.

Pathogenesis of Bacterial Infections. 2020. https://nios.ac.in/media/documents/dmlt/Microbiology/

Interaction of Various Components of Staphylococcus aureus. Pearce, Paul J. 1973 www.thepearcefoundation.org

The Microbial Battlefront: Surfaces

By Rodney E. Rohde, PhD, MS, SM(ASCP) CMSV CM,MBCM, FACSc

This column originally appeared in the April 2022 issue of Healthcare Hygiene magazine.

A 2021 review article in Frontiers Bioengineering and Biotechnology discusses what I am calling the “microbial battlefront.” This so-called battlefront – the surface – alongside the many mechanisms of microbial attachment to surfaces has long been a topic of study. This interaction of microbes, particularly bacteria, with surfaces has far reaching and critical implications in a diverse range of areas, including infection and transmission dynamics, formation of biofilms, biofouling, and bioenergy to name just a few.

By definition, a biofilm is a three-dimensional structure formed because of microorganism’s surface sensing, initial adhesion to surfaces, followed by subsequent colonization and production of an extracellular polysaccharides matrix (EPS). The sticky and glue-like matrix substance is structured and act as “smart communities” by bacteria. Like enemies, the bacteria become entrenched, and the biofilm community creates actual channels much like trench warfare where there is a hidden and protected route from the external environment to the internal surface environment for delivery of nutrients and waste byproducts allowing for ongoing colonization and maturation for the embedded bacteria. Even more diabolical, once the microorganisms mature, they shed and move from the matured biofilm to join another biofilm community or to become a pioneer of a new one. True cunning by these microbial adversaries. Like any enemy or opposition, those of us in healthcare and other industries must work to better understand their makeup and mechanisms of action.

In the review article, the authors lay out the key research areas that help us to better understand the microbial battlefront – the surface. The two key areas discussed include surface properties and environmental factors. Briefly, I will highlight the primary areas with respect to the characteristics attributed to how they impact the healthcare environment.

Surface Properties
The authors primarily focus on the following surface properties: surface charge density, surface wettability, surface roughness, surface topography, and surface stiffness. Due to the general makeup of bacterial cell walls from carboxyl, amino, and phosphate groups, the overall bacterial surface is a negative charge. Generally, we see more adhesion and biofilm EPS accumulation on positively charged surfaces although some studies show trends for initial attachment and later biofilm formation can be variable. In terms of sterilization and disinfection, one might consider surface selection. The interactions between solid and liquid phases define surface wettability. The liquid phase “wets” the surface of a solid surface by maximizing its area in contact with the surface. Surfaces with low surface energy and liquids with high surface tension tend to reduce surface wettability and vice versa in this direct relationship.

While the authors state that broad generalizations can’t be made, there is an argument for engineered materials and surface treatments creating an extreme water contact angle – either superhydrophobic or superhydrophilic surfaces that can limit bacterial adhesion – playing a part in this battlefront. Surface roughness increases the surface area available for bacterial attachment and provides a scaffold for adhesion and can provide protection for bacteria versus shear forces which would help bound bacteria to resist being detached. Research consensus shows that as surface roughness increases, bacterial adhesion and biofilm formation also increases. Interestingly, bacteria are capable of sensing mechanical cues associated with natural and artificial physical features, such as the topography of surfaces. For example, topography alternations can affect the expression of bacterial adhesins.

Topography has important implications for “sheltering” of bacteria and stronger adhesion when the dimensions (e.g., space) is larger than a single bacterium. In a sense, the less topography helps to deter sheltering. Surface stiffness is an indication of if material is softer and more elastic or harder and less elastic. This review states that investigations on the underlying mechanism in this topic are not yet sufficient.

Environmental Factors
Fluid dynamics and bacterial motility are the primary focus areas regarding environmental factors. One might think about fluid dynamics in the sense of the human body – dental plaques are subject to salivary and gingival crevicular fluid flow and the way fluid flows in a catheter microenvironment. These hydrodynamic conditions can enhance or interfere with bacterial sensing and overall biofilm formation.

One study in the review showed that shear flow enhances biofilm formation by increasing the EPS production and strength of the EPS-matrix in Staphylococcus aureus. In other words, a strong flow likely triggers S. aureus to express more EPS genes for stronger attachment. Bacteria and other microbes can be broadly divided into motile and non-motile bacteria. At the simplest understanding of motility, motile bacteria can “search the environment” for the most suitable surface areas to attach to while non-motile bacteria must rely on gravity and other forces to participate in sensing. Generally, bacterial surface appendages such as flagella can play an important role in the adhesion by inducing a more dynamic response of motile bacteria to surface properties than non-motile bacteria. Once bacteria adhere to surfaces, motile bacteria can settle biofilms faster than non-motile bacteria by attracting free bacteria through chemotaxis and quorum sensing.

It is critical for those involved in healthcare and community infection control and prevention to understand the theoretical and applied research at the battlefront of microbes and surfaces. Likewise, the industries that play a role in the development of antibacterial and antimicrobial surfaces must continue to conduct robust research that looks at more complex surface and environmental factors. For example, the focus must shift from a single surface parameter and its effect on adhesion to efforts assessing the impact of multiple surface parameters on bacterial adhesion, including the effect of temperature.

For a complete understanding of this review, refer to the paper: Sherry, et. al. Implication of Surface Properties, Bacterial Motility, and Hydrodynamic Conditions on Bacterial Surface Sensing and Their Initial Adhesion in Front. Bioeng. Biotechnol., 12 February 2021. https://doi.org/10.3389/fbioe.2021.643722

Update: The NCEZID and Candida auris

By Paul J. Pearce, PhD

This column originally appeared in the March 2022 issue of Healthcare Hygiene magazine.

The National Center for Emerging and Zoonotic Infectious Diseases (NCEZID) works to protect people from emerging and zoonotic infections ranging from A to Z—anthrax to Zika. We live in an interconnected world where an outbreak of infectious disease is just a plane ride away.

Candida auris is an emerging fungal (yeast) pathogen that presents a serious global health threat. The Centers for Disease Control and Prevention (CDC) and NCEZID are concerned about C. auris for these main reasons:

1. It is often multidrug-resistant, meaning that it is resistant to multiple antifungal drugs commonly used to treat Candida infections. Some strains are resistant to all three available classes of antifungals.
2. It is difficult to identify with standard laboratory methods, and it can be misidentified in labs without specific technology. Misidentification may lead to inappropriate management. It has caused outbreaks in healthcare settings, so it is important to quickly identify C. auris in a hospitalized patient so that organizations can take special precautions to stop its spread.
3. C. auris is typically acquired in healthcare settings, so most healthy people are not at risk. It is passed from person-to-person through the hands of healthcare personnel or by contaminated medical devices like catheters or ventilators. Patients with C. auris may be put under special precautions, such as being placed in an isolation room. This may continue even after treatment because they may still have C. auris on their skin or other sites on their body. Practice proper hand hygiene and use of personal protective equipment (PPE) such as gloves, masks, and gowns. Patients should make sure to carefully follow instructions from their doctor regarding antifungal medications.
4. Frequently recommended and used environmental cleaners and disinfectants may not be effective in controlling or killing C. auris.

The NCEZID was established in 2010 with a mission and scientific activities that trace back to the earliest days of the CDC, including protecting against and responding to infectious disease outbreaks. NCEZID is responsible for the prevention, control, and management of a wide range of infectious diseases, including rare but deadly diseases such as anthrax and Ebola virus disease, as well as more common illnesses like foodborne disease and healthcare-associated infections. NCEZID is one of the agency’s principal sources of epidemiologic, clinical, and laboratory expertise for bacterial, viral, and fungal pathogens as well as infectious diseases of unknown origin. The nation relies on NCEZID to protect the country from more than 800 dangerous pathogens. C. auris falls in the category of emerging, opportunistic pathogens that is a threat to patients in healthcare settings.

Why is Candida auris a problem?
• It causes serious infections, such as bloodstream and other types of invasive infections, particularly in patients in hospitals and nursing homes who have many medical problems. More than 1 in 3 patients die within a month of being diagnosed with an invasive C. auris infection.
• It is often multidrug-resistant. Antifungal medications commonly used to treat other Candida infections often don’t work for C. auris. Some C. auris isolates are resistant to all three major classes of antifungal medications.
• It is becoming more common. Although C. auris was just discovered in 2009, the number of cases has grown quickly.
• It is difficult to identify. C. auris can be misidentified as other types of fungus unless specialized laboratory methods are used. Correctly identifying C. auris is critical for starting measures to stop its spread and prevent outbreaks.
• It can spread and cause outbreaks in healthcare facilities. Just like other multidrug-resistant organisms such as carbapenem-resistant Enterobacteriaceae (CRE) and methicillin-resistant Staphylococcus aureus (MRSA), C. auris can be transmitted in healthcare settings and cause outbreaks. It can colonize patients for many months, persist in the environment, and withstand some commonly used healthcare facility disinfectants.

What should I do if there is C. auris in my facility?
1. Check the CDC website for the most up-to-date guidance on identifying and managing C. auris: www.cdc.gov/fungal/candida-auris.
2. Report possible or confirmed C. auris test results immediately to your public health department.
3. Ensure adherence to CDC recommendations for infection control, including placing patients infected or colonized with C. auris on Transmission-Based Precautions and, whenever possible, in a single room; making sure gown and gloves are accessible and used appropriately; reinforcing hand hygiene as well as coordinating with environmental services (EVS) to monitor and ensure the patient care environment is cleaned using a disinfectant with an Environmental Protection Agency claim for C. auris or, if not available, for Clostridioides difficile. These products can be found at www.cdc.gov/fungal/candida-auris/c-auris-infection-control.html. Some disinfectants used in healthcare facilities (e.g., quaternary ammonium compounds [QACs]) may not be effective against C. auris, despite claims about effectiveness against C. albicans or other fungi. Work with the EVS team to monitor the cleaning process. Review EPA Lists N and P for disinfectants that are recognized as effective against C. auris.
4. After consulting with public health personnel, screen contacts of case-patients to identify patients with C. auris colonization. Use the same infection control measures for patients found to be colonized.
5. When a patient is being transferred from your facility (to a nursing home or other hospital), clearly communicate the patient’s C. auris status to receiving healthcare providers.

Paul J. Pearce, PhD, leads the Pearce Foundation for Scientific Endeavor.

References:
https://www.cdc.gov/ncezid/pdf/ncezid-strategic-plan-2018-2023-508.pdf
https://www.epa.gov/pesticide-registration/list-p-antimicrobial-products-registered-epa-claims-against-candida-auris
www.thepearcefoundation.org

Fish Aquariums: A Transmission Source

By Rodney E. Rohde, PhD, MS, SM(ASCP) CMSV CM,MBCM, FACSc

This column originally appeared in the February 2022 issue of Healthcare Hygiene magazine.

In September 2021, I reported on a Burkholderia pseudomallei (melioidosis) outbreak of four cases of from Georgia, Kansas, Minnesota and Texas. The first case (fatal) identified in March 2021 occurred in Kansas. The second and third cases, both identified in May 2021 in Minnesota and Texas, were hospitalized for extended time then discharged to transitional care facilities. The most recent case died in the hospital and was identified post-mortem in late July 2021 in Georgia. All cases had no history of traveling abroad from the United States. Melioidosis signs and symptoms are varied and nonspecific, and may include pneumonia, abscess formation, and blood infections.

All four melioidosis cases initially presented with symptoms ranging from cough and shortness of breath to weakness, fatigue, nausea, vomiting, intermittent fever, and rash on the trunk, abdomen, and face. Two cases, one fatal, had several risk factors for melioidosis, including COPD and cirrhosis. The other two cases had no known risk factors for melioidosis. Genomic analysis of the strains strongly suggested a common source (e.g., imported product or animal). The source is unknown to date despite environmental sampling, serological testing, and family interviews.

The Centers for Disease Control and Prevention (CDC) recently reported a 56-year-old woman, hospitalized on Sept. 20, 2019, likely acquired melioidosis via novel transmission of B. pseudomallei from a freshwater home aquarium in the December 2021 issue of Emerging Infectious Diseases. The Maryland woman is the first known person to have this severe tropical infection by this new transmission route.

The patient history showed diabetes and rheumatologic disease. She was hospitalized because of fever, cough, and chest pain with onset 2 days earlier. Her ongoing medications indicated immunosuppressives (methotrexate, azathioprine, and prednisone) until 1 month before she became symptomatic. Multiple blood cultures were taken on days 1-4 which grew B. pseudomallei, without evidence of endocarditis or intravascular seeding.

Other clinical data presented a thoracic radiograph on day 0 consistent with pneumonia. A non-contrast computed tomography (CT) scan on day 3 showed air space consolidation in the right lower lobe consistent with pneumonia. Other notable clinical laboratory results at presentation included an increased leukocyte count of 22,800 cells/μL (reference range 4,500 to 11,000 cells/μL) and a decreased sodium level of 125 mmol/L (reference range 135‒145 mmol/L).

Despite weeks of meropenem (Merrem), she developed evidence of a lung abscess, and trimethoprim/sulfamethoxazole (Bactrim) was added. Ultimately, the patient required a 12-week course of antibiotics for eradication therapy and resolution.
I started my career in public health at the Texas Department of State Health Services as a public health microbiologist and molecular epidemiologist in the Zoonosis Control Division. During that decade, I had the opportunity to spend two sessions with the CDC in the Rabies Laboratory as a Visiting Scientist. During those formative years of my professional career, I will always remember the critical and sometimes lifesaving advice to not forget about doing a deep dive on a patient history. The melioidosis case in Maryland is significant to that advice.

CDC epidemiologist Patrick Dawson, PhD, first author of the report, told Medscape Medical News that although outbreak investigators always ask about pet ownership, they have not explicitly asked about fish. In this case, the patient did not volunteer exposure to the fish. If I am being honest, I am not sure I would have either. Typically, physicians and epidemiologists know to ask about exposures from animals, the environment (e.g., soil, water, etc.) and travel. While we know fish can be a source of different microbial infections, since this patient had not mentioned it, the epidemiologists and others did not think about.

However, when there was a visit to patient's home, "one of the first things they saw was a few aquariums," Dawson said. Seeing the water and knowing "that most freshwater tropical fish in the U.S. are imported from Southeast Asia" led them to culture specifically for B. pseudomallei, which can be difficult for the microbiology lab to identify.

The investigative epidemiology team discovered she had bought her fish 6 months earlier. Through environmental sampling at the local pet store, they did not discover the bacteria there. Eventually, the team worked with the national brand to find where the fish originated. Ultimately, an exact matching isolate could not be identified after so many months had passed, but they found a positive PCR for B. pseudomallei in a water sample from imported fish in Los Angeles.

Advice for the public:
• Wash your hands before and after contact with an aquarium
• If you have cuts or wounds, wear gloves while working with an aquarium or cleaning fish
• If immunocompromised (including younger children), don’t handle fish or aquariums
• Aquatic zoonoses (infections from water) are important because an estimated 11.5 million U.S. households have pet fish, totaling about 139 million freshwater fish.

Eradicating the Deadliest Predators from the Microbial Jungle

By Paul J. Pearce, PhD

This column originally appeared in the January 2022 issue of Healthcare Hygiene magazine.

An article in the August 2020 edition of Healthcare Hygiene magazine, “A Better Way to Understand Your Microbial Jungle: What’s in There and How to Know It’s Gone,” highlighted the requirement to know the microbial enemies and deadliest predators that create the complex microbial jungle responsible for healthcare-associated infections (HAIs). The following describes the most common microorganisms that are associated with HAIs and effective methods, means and equipment that have been successfully used to eradicate these pathogenic microorganisms.

Acinetobacter is a group of bacteria commonly found in soil and water. Outbreaks of Acinetobacter infections typically occur in intensive care units and healthcare settings housing very ill patients. While there are many types or “species” of Acinetobacter and all can cause human disease, Acinetobacter baumannii accounts for about 80 percent of reported infections. Acinetobacter infections rarely occur outside of healthcare settings.

Healthcare facilities in several countries have reported that a type of yeast called Candida auris has been causing severe illness in hospitalized patients. In some patients, this yeast can enter the bloodstream and spread throughout the body, causing serious invasive infections. This yeast often does not respond to commonly used antifungal drugs, making infections difficult to treat. Patients who have been hospitalized in a healthcare facility a long time, have a central venous catheter, or other lines or tubes entering their body, or have previously received antibiotics or antifungal medications, appear to be at highest risk of infection with this yeast.

Vancomycin-intermediate Staphylococcus aureus (also called S. aureus) and vancomycin-resistant Staphylococcus aureus are specific staph bacteria that have developed resistance to the antimicrobial agent vancomycin. Persons who develop this type of staph infection may have underlying health conditions (such as diabetes and kidney disease), devices going into their bodies (such as catheters), previous infections with methicillin-resistant Staphylococcus aureus, and recent exposure to vancomycin and other antimicrobial agents.
Vancomycin-resistant Enterococci are specific types of antimicrobial-resistant bacteria that are resistant to vancomycin, the drug often used to treat infections caused by enterococci. Enteroccocci are bacteria that are normally present in the human intestines and in the female genital tract and are often found in the environment. These bacteria can sometimes cause infections. Most vancomycin-resistant Enterococci infections occur in hospitals.

Gram-negative bacteria cause infections including pneumonia, bloodstream infections, wound or surgical site infections, and meningitis in healthcare settings. They are resistant to multiple drugs and are increasingly resistant to most available antibiotics. Gram-negative infections include those caused by Klebsiella, Acinetobacter, Pseudomonas aeruginosa, and E. coli, as well as many other less common bacteria.

Clostridioides difficile (C. diff) causes life-threatening diarrhea. It is usually a side-effect of taking antibiotics. These infections mostly occur in people 65 and older who take antibiotics and receive medical care, people staying in hospitals and nursing homes for a long period of time, and people with weakened immune systems or previous infection with C. diff.

The 2020 National and State Healthcare-Associated Infections Progress Report provides a summary of select HAIs across four healthcare settings: acute care hospitals (ACHs), critical access hospitals (CAHs), inpatient rehabilitation facilities (IRFs) and long-term acute care hospitals (LTACHs). Data from CAHs are provided in the detailed technical tables but not in the report itself. The designation of CAH is assigned by the Centers for Medicare and Medicaid Services (CMS) to hospitals that have 25 or fewer acute-care inpatient beds and that maintain an annual average length of stay of 96 hours or less for acute-care patients. IRFs include hospitals, or part of a hospital, that provide intensive rehabilitation services using an interdisciplinary team approach. LTACHs provide treatment for patients who are generally very sick and stay, on average, more than 25 days.

The 2020 National and State Healthcare-Associated Infections Progress Report, along with the detailed technical tables, provides national- and state-level data about HAI incidence during 2020. The report is designed to be accessible to many audiences. National and state HAI reports will be made available for viewing, downloading, and printing from the Antibiotic Resistance and Patient Safety Portal. For detailed methods, references, and definitions, refer to the Technical Appendix and Glossary within this report. For more information, please visit CDC’s Healthcare-Associated Infection Data Reports website.

Paul J. Pearce, PhD, leads the Pearce Foundation for Scientific Endeavor.

References:
https://www.cdc.gov/hai/data/portal/progress-report.html
https://www.cdc.gov/hai/organisms/organisms.html