A Better Way to Understand Your Microbial Jungle: What’s In There and How to Know When It’s Gone
By Paul Pearce PhD; and John Scherberger, FAHE
How often is the comment "I know clean when I see it" made? How often have the people who said it given any thought to how inane and uninformed the comment is? Indeed, everyone reading this article has never said it, for the pure ignorance it conveys, or have they?
Surely healthcare professionals, even those on the purely business side of healthcare, know that "clean" is a subjective state. Not only do healthcare professionals struggle with defining "clean," dictionaries struggle to define "clean." Dictionary.com may come closest when it describes it as "being free from dirt; unsoiled; unstained; free from foreign or extraneous matter; free from pollution; unadulterated; pure."
But science cannot rest on a general definition. Scientists, particularly microbiologists, know the dangers that disease-causing bacteria, yeasts, fungi, protozoa, prions, viruses, and other microorganisms– commonly referred to as pathogens – may be present. They are on surfaces, in water, and the atmosphere, even when the eyes see something that appears to be pristine, pure, untainted, and welcoming.
A recent report issued by the Centers for Disease Control and Prevention (CDC), Antibiotic Resistance Threats in the United States, 2019 (2019 AR Threats Report) (https://www.cdc.gov/drugresistance/pdf/threats-report/2019-ar-threats-report-508.pdf) provides a detailed and problematical list of dangerous infections and potential disease-causing pathogens. Why potential? Because what is a pathogen to one person may not be a pathogen to another person. The challenges faced by microbiologists, epidemiologists, infectious disease doctors, and medical staff are endless.
The causes of healthcare-associated infections (HAIs), while similar in their association to a disease condition, are frequently different in their resistance to antimicrobials and disinfectants. They have varying habitat requirements, environmental requirements for existence, growth, and reproduction. The means, skills, capabilities, and competencies needed to detect them in a healthcare setting accurately are varied and unique.
The 2019 AR Threats Report provides the latest 2019 U.S. death and infection estimates. The report underscores the continued threat of antibiotic resistance in the United States and offers extensive and helpful profiles of each of the six ESKAPE pathogens. The name comes from the first letter of each pathogen: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.
It is essential to know the report is pre-COVID-19; it presents a dilemma facing healthcare in 2019 and beyond, even during the COVID-19 pandemic. Healthcare is not only facing the SARS-CoV-2 virion and the COVID-19 it causes; it must remain engaged in the battles presented by the 2019 AR Threats. Microbiologists, antibiotic resistance threats present in the future.
According to the 2019 AR Threats Report, "more than 2.8 million antibiotic-resistant infections occur in the U.S. each year, and more than 35,000 people die as a result." Also, 223,900 cases of Clostridioides difficile occurred in 2017, and at least 12,800 people died. https://www.cdc.gov/drugresistance/pdf/threats-report/2019-ar-threats-report-508.pdf
Those are staggering numbers, but nowhere near the COVID-19 death toll in the U.S. As of July 28, 2020, the U.S. has confirmed more than 4.3 million cases of coronavirus, which has resulted in at least 148,298 deaths. During the period of July 24-28, 2020, the U.S. was averaging more than 1,000 per day.
But these are not just numbers; they are people. They are people who loved and were loved; people who had families; and people who impacted hundreds of thousands of other people during their lives. Science must never ignore nor grow old of the personal human aspect of infections. EvSOP© is dedicated to helping environmental services (EVS) professionals save lives and maintain everyone’s dignity, because everyone is important.
Deaths are not just numbers; they are people who meant something, people that mean something. It is for those people who are saved and return to their families and lead productive lives that microbiologists work so hard – to save lives. Too often in their haste to accomplish their tasks, nurses and others ask for assistance with "the COVID in room 219" or the "Code Brown (C. difficile) patient in room 505." Patients must never be relegated to disease status.
This article proposes to describe the microbial jungle found in healthcare environments and review the recognized evidence-based practice guidance for detecting microbial contaminants that may be present before and after cleaning and disinfection.
The CDC’s list of ESKAPE Pathogens can be accessed at: https://www.cdc.gov/drugresistance/biggest-threats.html
Biofilms are densely packed communities of microbial cells that grow on living or inert surfaces and surround themselves with secreted polymers. Many bacterial species form biofilms, and their study has revealed them to be complicated and diverse. The structural and physiological complexity of biofilms has led to the idea that they are coordinated and cooperative groups, analogous to multicellular organisms.
Current research and studies conducted by scientists at Cardiff University, Dr. Katarzyna Ledwoch and professor Jean-Yves Maillard, introduce us to the latest in another type of biofilm, dry surface biofilms (DSB). DSB are complex microbial communities formed and grown in dry habitats. Much less attention has been paid to dry biofilms compared to most commonly researched wet/hydrated biofilms. DSB colonize various materials from textile (chair), hard surfaces including plastic (PVC, PP), lacquered wood, wood, metal (stainless steel) to many others. DSB have been isolated from diverse environmental conditions: low moisture, varying temperature and nutrient levels.
Biofilm is the invisible film that is present and growing on almost all surfaces in hospitals, restaurants, cruise ships, entertainment venues, hotels, and homes. It is the accumulation of microorganisms and their numerous chemical components. Whenever people are, they add to the already existing jungle of germs.
Real-world hospital testing for dry biofilm presence and removal was most notably conducted by Ledwoch, et al., scientists at the School of Pharmacy and Pharmaceutical Sciences at Cardiff University and published is three articles: Candida auris Dry Surface Biofilm (DSB) for Disinfectant Efficacy Testing (2018); Beware biofilm! Dry biofilms containing bacterial pathogens on multiple healthcare surfaces: a multicenter study (2018): and Artificial dry surface biofilm models for testing the efficacy of cleaning and disinfection (2019).
The results shared by Ledwoch, et al. as to the efficacy of various microfiber wipes and wipers by EVS staff categorically documented the effectiveness and superiority of Healthcare-Grade Ultrafine Microfiber (H-GUM) in the physical removal of dry biofilm. This type of microfiber was the only beneficial cloth to effect physical disruption of biofilm, be it wet or dry. H-GUM is constructed of split bi-component fibers and split to such fine triangular filaments. It disrupts the physical condition of biofilm to such an extent that the biofilm is removed.
Bacteria itself contribute to the microbial jungle through waste products. Bacterial waste products are endotoxins, exotoxins, cellular debris, proteins, lipids (fats), and mucopolysaccharides (known in the microbiological trade as germ snot!).
If the jungle floors of Central and South America were casually looked at, they would appear similar, yet they are vastly different. They are different because of the variety of flora and fauna living and dying there and are teeming with organic waste and infinite microbes and bacteria. One would also find moist and dry surface biofilm (DSB) serving as a festering microbial breeding ground and germ graveyard, the equivalent of the sludge found in septic tanks. Just as jungles from different parts of the world are different, the "jungles" found in hospitals are different because of where they are. Get the picture?
Why DSB Can Be a Problem
• DSB are widespread on surfaces in hospitals
• DSB contribute to pathogens survival and HAIs despite cleaning and disinfection
• DSB cannot be detected by swabbing or contact plates
• All biofilms harbor Gram-positive bacteria, including pathogens associated with HAIs
• DSB regrow within one day when provided with nutrients
How to solve the problem:
• Improved hand hygiene
• Improved cleaning with Healthcare Grade Ultrafine Microfiber (HGUM)©
• Disinfectants targeting DSB
• Improved monitoring of contamination levels
Know the Enemies
The complexity of the healthcare-associated microbial jungle requires accurate, reliable reproducible testing. The key to effective testing requires a standardized sample collection and testing procedure. The results acquired represent a precise picture of the microbial jungle present in the facility and the patient risks associated with the environment. The goal of identifying the targeted microbe or pathogen is one of the first steps to breaking the chain of infection.
Microbiologists working in laboratories can be allies to infection preventionists (IPs). By identifying a pathogen, its species and the genome, the team is equipped with the needed information to make informed decisions. The facility antibiogram (bugs & drugs report) helps to identify the pathogens within a facility and the antibiotics prescribed to treat infections. That is why an IP focuses on antibiotic stewardship.
The EVS team does not prescribe antibiotics for patients, yet they are teamed with IPs in specifying appropriate EPA-registered, hospital-grade disinfectants for the environmental pathogens. This use of disinfectants is a form of antimicrobial stewardship; just as the human body has many organs and life-sustaining systems that are factors in a patient's health, a hospital building has many critical systems that require close monitoring and care.
A hospital is comparable to a human body. The HVAC system provides clean air, like the lungs. Fresh, clean, safe water circulates through potable water-pipe systems are similar to the blood. The circulatory system of arteries, veins, coronary, and portal vessels, is required throughout the facility. The waste line plumbing is similar to the gastrointestinal tract, and the largest organ in the body, the skin, is analogous to the external hospital surfaces. Water consumed by the human body is essential, just as water added to EPA registered, hospital-grade disinfectants is required for the disinfectant to work correctly.
Know the EVS Arsenal for the War on Pathogens
EVS teams must be equipped with knowledge, proper cleaning tools, EPA-registered and hospital-grade disinfectants, plus sufficient time to incorporate:
1. Microbiological sampling of the environment
2. Assessing the efficacy of wiping cloths and mops at:
a) Removing Surface microorganisms (bioburden) and other materials like dust, soil, blood, and bodily fluid.
b) Moist biofilm and dry surface biofilm (DSB) destruction and removal
c) Endotoxin removal
3. Assessing the efficacy of reusable and reprocessed wiping cloths and mops. (e.g., launderable to CDC guidelines (HICPAC 2003).
Microbiologists can assist EVS and IP teams in providing knowledge of the pathogens and how to remove and destroy the threats to human health. Additionally, they can give validation of useful products, processes and programs. Depending on the type of product and its purpose, there are three main categories of microbial quality control tests requiring the use of growth media.
Guidelines for Microbial Examination of Non-Sterile Products
The microbial limits test procedures are performed to determine whether a non-sterile product complies with given specifications for microbial quality. Such non-sterile products include cosmetic, healthcare and pharmaceutical products. The microbial enumeration tests are a range of tests manufacturers can use to help ensure the bioburden of finished goods remains within safe limits. This is typically used in pharmaceutical product manufacturing for non-sterile products, we are mentioning only as a point of reference of an established best practice to compare/contrast for healthcare textiles although not required or warranted by CDC as actual transmission of infection has been determined insignificant through healthcare textiles in outsourced laundries. Most contamination is during improper handling or laundry within the hospital.
The microbial limits test procedures are performed to determine whether a non-sterile product complies with given specifications for microbial quality. Such non-sterile products include cosmetic, healthcare and pharmaceutical products. The microbial enumeration tests are a range of tests manufacturers can use to help ensure the bioburden of finished goods remains within safe limits. This is typically used in pharmaceutical product manufacturing for non-sterile products, we are mentioning ONLY as a point of reference of an established best practice to compare/contrast for healthcare textiles although not required or warranted by CDC as actual transmission of infection has been determined insignificant through healthcare textiles in outsourced laundries. The majority of contamination is during improper handling or laundry within the hospital.
As described in US Pharmacopoeia, USP <61> is a microbial enumeration test that provides a quantitative evaluation of the microbial content of a sample, also known as microbial bioburden testing or microbial limits testing. Simply put, USP <61> is what gives the number of colony-forming units (cfu) in a given sample. USP <62> is the method used to determine what organisms are present within a sample.
Returning to the jungle analogy, knowing that there are 20 animals in an area is knowledge, but knowing what those 20 animals are is empower. As established by Sattar et al., there is statistical variations in log reduction based upon type of substrate or cloth used to wipe surfaces. That is why the work outlined in the paper, Decontamination of high-touch environmental surfaces (HITES) by wiping: Assessment of a carrier platform for quantitative and field-relevant assessment of pathogen inactivation, removal and transfer, is helpful as we continue to evaluate the device, and the procedure, based on to address a major gap in assessing wiping of HITES.
Barring no-touch technologies, chemical decontamination of high-touch environmental surfaces invariably incorporates wiping, but current and widely accepted methods to assess environmental surface disinfectants do not incorporate that physical action (Sattar 2010) so critical for dislodging and removing dried contamination to allow better access to and action by the disinfectant. In view of this, test data from ‘static’ (without any wiping action) test protocols, and label claims based on them, only show the microbiocidal potential of a given formulation without indicating its ability to perform under actual field use. There is, therefore, a need to generate test data on such formulations via a ‘dynamic’ (combining physical action of wiping with chemical disinfection process) test protocol reflecting field use of the process. Such information would better inform disinfectant manufacturers, government regulators as well as infection preventionists.
It is with this example in mind that EvSOP© tested most commercially available wipes and mops for evidence-based outcomes to be shared in the future series on science-based cleaning. In her research paper, How do we assess hospital cleaning? A proposal for microbiological standards for surface hygiene in hospitals (Journal of Hospital Infection (2004) 56, 10–15), Dancer stated, “Cleaning in general has two main functions: first: non-microbiological, to improve or restore appearance, and prevent deterioration. Second, microbiological, to reduce the numbers of microbes present, together with any substances that support their growth or interfere with disinfection.”
These are the two basic functions we need to look at for EPA-registered, hospital-grade disinfectants to have full efficacy, and to remove potential sources of infection. Notice the importance of the physical removal in the CDC Guidelines for Environmental Infection Control in Health-Care Facilities, section 2b:
Disinfectant/detergent formulations registered by EPA are used for environmental surface cleaning, but the actual physical removal of microorganisms and soil by wiping or scrubbing is probably as important, if not more so, than any antimicrobial effect of the cleaning agent used.
So, evaluation of a cleaning tool -- albeit wiper or mop -- must include how it performs in both the cleaning and disinfection process. It must trap, capture, and remove bacteria, virions, spores, dirt, dust, soil, blood, and body fluid, while absorbing and eluting the disinfectant to achieve the desired wet contact time per the manufacturer’s label.
At the outset of the EvSOP© series, readers were introduced to a set of criteria upon which each product should be tested. Due to the COVID-19 pandemic, most people know the importance of cleaning and disinfecting the environment to ensure a hygienic environment. What appears to be clean and assumed to be hygienic can contaminate the environment and cause a healthcare-acquired infection.
With the conventional methods, the method of reporting a result from a test is by colony forming units (CFU) per unit of testing (typically CFU per mL or per 100mL). A CFU does not necessarily equate with a number of microorganisms present in the sample but it does provide an indicator of the bioburden load. This is because a CFU is an estimate of one or more microbial cells which, on the introduction of microbial growth media, can form macro-colonies under the conditions of the test. One colony forming unit is expressed as 1 CFU. In relation to pharmaceutical processing, bioburden testing is implemented in order to assess the quality of the starting materials and to track process hygiene as the product is being manufactured.
Healthcare-Grade Ultra Microfiber (H-GUM) used in healthcare facilities is not expected to be sterile, only hygienic. Bioburden assessment is not a requirement of the final product. To expect non-sterile products used in a non-sterile environment to produce a sterile environment or surface is non-sensical, unrealistic, and beyond the realm of the necessary. It should be expected that infection prevention textiles used by EVS in a non-sterile environment may contain a level of bioburden, and bioburden is not another name for pathogens. H-GUM is effective at providing a log-105 reduction of surface bacteria in and of itself and, with the proper disinfectant and use, a log-107 is attainable. When laundered according to CDC guidelines, H-GUM releases bacteria, spores, and other biomaterial sufficiently to render the product hygienic and effective at removing bioburden from surfaces sufficient to rendering them hygienic.
What to remember from all of this? Quite simply, EVS teams must be equipped with knowledge, proper cleaning tools including H-GUM, EPA-registered and hospital-grade disinfectants, and sufficient time to incorporate them. When all four of these essential factors are in place, the microbial jungle is not so frightening; that is, at least until someone with unwashed hands touches a surface.
Paul J. Pearce, PhD, has more than 40 years of medical and environmental laboratory testing and teaching experience. Pearce’s training and work in microbiology, chemistry, human physiology and medicine have enabled him to help thousands of people as they strive to improve their lives.
John Scherberger, FAHE, is the owner of Healthcare Risk Mitigation in Spartanburg, S.C. He is a subject matter expert in healthcare environmental services, healthcare linen and laundry operations, and infection prevention.