Pathogen resistance is deadly.
It is a very real problem in and away from healthcare entities, and extends way beyond antibiotic resistance related to infection-fighting in the human body.
Mountains of evidence prove that bacteria have an immense capacity to respond to chemical stress.¹ These organisms hold a miraculous ability to morph and thrive. And with the recent MRSA (methicillin-resistant Staphylococcus aureus) media craze, they even have been coined the true survivalists of all organisms in our ecosystem.
So, just as antibiotic use is now carefully thought out so too must special forethought be put into the chemicals and compounds used to destroy these microorganisms.
Clean Healthcare Environments?
Inanimate surfaces are increasingly noted as infection-spreading vectors. According to research, persistence of the following pathogens on inanimate surfaces runs frighteningly high.2
Most gram-positive bacteria, such as Enterococcus spp. (including vancomycin- resistant enterococci [VRE]), Staphylococcus aureus (S. aureus) (including MRSA), and Streptococcus pyogenes, survive for months on dry surfaces. It is also interesting to note that MRSA can survive for 11 days on a plastic patient chart, more than 12 days on a laminated tabletop and for nine days on a cloth curtain.³
The gram-negatives also hang around Acinetobacter spp., Escherichia coli (E. coli), Klebsiella spp., Pseudomonas aeruginosa, Serratia marcescens, and Shigella spp., all were found to have survived for months.² Other monthly settlers include mycobacteria, including Mycobacterium tuberculosis, and spore-forming bacteria such as Clostridium difficile (C. diff).
The not-as-lengthy residents, lingering for only a matter of days, include Bordetella pertussis, Haemophilus influenzae, Proteus vulgaris, and Vibrio cholerae. The lengthiest camper, however, was the fungal counterpart Candida albicans. Persistence of other yeasts ranged anywhere from 14 days (Candida parapsilosis) to as long as five months (Torulopsis glabrata).
Viruses also stick around. Those from the respiratory tract, such as corona, coxsackie, influenza, SARS or rhino virus, can linger for a few days on certain surfaces; and viruses from the gastrointestinal (GI) tract astrovirus, HAV, polio- or rota virus linger for as long as two months. Blood-borne viruses, such as HBV or HIV, can persist for more than one week, and herpes viruses have been shown to persist from only a few hours up to seven days.
These many examples mark the importance of effective, regular surface and environmental disinfection and cleaning measures.
A study conducted by researchers at Brigham and Womens Hospital and Harvard Medical School examined the role of environmental contamination and the accompanying relative odds of infection acquisition.4 According to the two groups of scientists, newly-admitted patients housed in a room in which the most recent occupant was MRSA-positive or VRE-positive, significantly increased the odds of acquisition for a MRSA-related or VRErelated infection. The two entities held a 20-month record of the rate of infection acquisition in patients admitted to such rooms and the results note that in a MRSA room, 3.9 percent of new patients acquired an infection. In the VRE room, 4.5 percent acquired a VRE infection.
As aforementioned, MRSA is peaking as a media craze and this small acronym/big bug grapples a lot of attention. The same rings true in recent research of its environmental tendencies.
In Ireland, for example, researchers tracked the environmental contamination of 25 isolation rooms that housed MRSA-infected patients.5 Sample results show that over half (53.6 percent) of the surface samples, over a quarter (28 percent) of the air samples, and just under half (40.6 percent) of the settle plates, all tested positive.
In the UK, healthcare professionals and other researchers and epidemiologists continue to debate the importance of hospital cleaning in relation to the increase or decrease of MRSA incidence.6 But some studies find more than half of the surface samples taken from the beds and the mattresses alone came back positive for MRSA,5 and study after study proves that MRSA prevails no matter the surface, nor its location in the world.
Japanese researchers found the following breakdown of MRSA contamination on the environmental surfaces they cultured:7
- 40.2 percent (41 of 102) of the bed linen samples
- 22.4 percent (19/85) of the overbed table samples
- 20.9 percent (18/86) of the bed siderail samples
- 2.7 percent (2/74) of the room door handles (inner side of patient rooms) samples
The researchers isolated MRSA from the palm in 29.6 percent of the 98 patients cultured, leaving them to conclude that MRSA in the patients palms had the most marked influence on MRSA contamination of their surrounding environmental surfaces.7
A study conducted at the Hospital of Saint Raphael located in New Haven, Conn. found that patients with diarrheal stools and heavy GI colonization with MRSA are associated with significantly greater environmental MRSA contamination.8 The items most commonly contaminated in this instance are bedside rails, blood pressure cuffs, television remote controls, and toilet seats.
Its long been recognized that hand transmission of pathogens is prevalent.9 Patients own hands are often the lethal weapon, as demonstrated in the above-mentioned study. Contaminated hands contaminate surfaces and vice-versa, and this too marks the importance of routine cleaning of the patient environment, equipment and other patient items and high-touch surfaces as an important component to the fight against nosocomial infections.9 Furthermore, the introduction of enhanced or additional cleaning practices have proven easier to implement than improvements in hand hygiene compliance.6
A good example of this is that of a simple yet effective strategy for reducing transmission of organisms from the anesthetic equipment to surgical patients in the department of anesthesia, critical care and pain medicine at the Royal Infirmary of Edinburgh.10 A new departmental policy of wiping the equipment with detergent wipes between cases resulted in a significant reduction of cultures containing pathogenic bacteria (about one-third of the previous findings before the intervention). The intervention was quick, easy and enthusiastically taken up by the majority of staff, the researchers note.
Short of having reprimanded military personnel scrubbing a hospital room with his/her toothbrush, more effective and rigorous use of current approaches to cleaning and decontamination is required, as well as consideration of newer technologies.5 Hospital hygiene is usually assessed visually, but this does not correlate with the true, unseen microbiological risk.6
German expert and longtime researcher on the topic, Markus Dettenkofer, MD, with the Institute of Environmental Medicine and Hospital Epidemiology, University Hospital, and the Institute of Environmental Medicine and Hospital Epidemiology and National Reference Center for Surveillance of Nosocomial Infections in Berlin/Hannover/Freiberg, Germany, reminds us that surface disinfection is only transient.11
Microbial contamination will have reached its former level within a few hours, he notes, and, he warns, the decontamination ability of the substances used must be carefully considered. Chemicals applied to surfaces to clean or disinfect require a certain amount of forethought. For example, as previously mentioned, prevention of resistance is highly important. Equal to that is the level of safety for patients, personnel and the environment, Dettenkofer notes.
Dettenkofer also points out that there are very real differences between the use of disinfectants on environmental surfaces and cleaning with detergents.12 New disinfectants, mainly peroxygen compounds, show good sporicidal properties and will probably replace more problematical substances such as chlorine-releasing agents, he writes.
No two hospitals are cleaned the same. Some general cleaning protocols exist, but successful eradication of offending organisms depends on how vehemently they are implemented.
A group of researchers recently evaluated four common hospital cleaning methods: mop and vacuum; spray clean; a wet scrub for floors; and one steam cleaning method for curtains.13 Following microbiological screening, results found that all floor cleaning methods reduced the overall microbial load, although high counts of bacterial pathogens occasionally persisted. Spray cleaning gave marginally better results than traditional mopping and vacuuming, and wet scrubbing significantly reduced levels of coagulase-positive staphylococci, which, in combination with routine methods, produced an effect that persisted for at least a week, according to results. Steam cleaning of the curtains also reduced microbial counts, but it had little effect on S. aureus and other potential pathogens.
The effectiveness of another hospitals cleaning regimen was assessed in another 2007 study.14 For the selected sites evaluated over a 14-day period, the methods were highly variable. The cleaning regimen was then slightly modified in two stages, both changes involving a rinse stage and substituting cloths with disposable paper towels. One modification continued using the existing detergent; the other replaced detergent with a quaternary ammonium sanitizer. Both modifications yielded significantly lower and more consistent bacterial counts, and assessment of residual organic soil demonstrated that failure rates fell from 86 to 100 percent after existing cleaning methods, to zero to 14 percent after modified cleaning. The researchers conclude that incorporating a quaternary ammonium sanitizer into the cleaning regimen produced a further improvement in cleaning efficacy.
A private research service hired by Louis Stokes Cleveland Veterans Affairs Medical Center located in Cleveland, Ohio assessed the adequacy of cleaning practices in rooms of patients with C. diff.-associated diarrhea (CDAD) and VRE colonization or infection.15 The group assessed the environment following standard housekeeping cleaning and again after disinfection with 10 percent bleach. The housekeeping staff was then briefed on best practices for environmental cleaning and the research team followed up for a 10-week period.
Of the 17 rooms of patients with VRE colonization or infection, 16 (94 percent) had one or more positive environmental cultures before cleaning vs. 12 (71 percent) after housekeeping cleaning. None had positive cultures after bleach disinfection by the research staff.
Of the nine rooms of patients with CDAD, all (100 percent) displayed positive cultures prior to cleaning vs. 7 (78 percent) after housekeeping cleaning, and 1 (11 percent) had positive cultures after bleach disinfection by research staff.
After the educational intervention, rates of environmental contamination after housekeeping cleaning were significantly reduced.
Somethings In the Air
Todays trends are focusing on a more vivacious killer of the insidious organisms lurking in a hospitals nooks and crannies one that doesnt require the historical elbow grease of the past. Hydrogen peroxide vapor (HPV) decontamination is fast picking up speed. Is it effective? Is it too good to be true to simply set a machine off in a room, walk away, and return to a clean, decontaminated environment?
Some studies point to an affirmative answer to these questions. For example, a prospective study conducted in the surgical wards of a London teaching hospital compared the effectiveness of standard cleaning with HPV decontamination as they both relate to MRSA virulence.16 After standard cleaning, all areas remained contaminated with 66 percent of 124 swabs yielding MRSA. However, after exposing six of those rooms to HPV, only one of 85 swabs yielded MRSA.
In another study, HPV decontamination was successful in completely eradicating MRSA from the environment, however, within 24 hours after readmitting patients, the organism was again isolated from five sites leaving the researchers hypothesizing that HPV has a rapid rate of recontamination.17 Another experiment found HPV effective in eradicating MRSA, VRE and gentamicin-resistant Gram-negative rod (GNR).18 Interestingly, no recontamination with VRE was identified, and no recontamination with MRSA and GNR was identified during the two days following HPV decontamination. Substantial recontamination was identified, however, approximately one week later.
Not quite as fancy as HPV, but air-related nonetheless, is the use of a portable high-efficiency particulate air (HEPA)-filtration unit. HEPA-filtration has been proven to significantly reduce MRSA environmental surface contamination.19 Also environmentally appealing, even something as simple as the use of copper surfaces instead of stainless steel can reduce the microbial count on surfaces, because the natural antimicrobial effect of copper on MRSA is fully effective in certain conditions.20
Another recent breakthrough (ironically, this coincides with effective wound care treatment) is the use of silver ions. Maureen P. Spencer, RN, M.Ed, CIC, infection control coordinator at New England Baptist Hospital, an orthopedic specialty hospital in Boston, and previously the director of infection control at Massachusetts General Hospital, tested the efficacy of SilverClene24, a new silver hospital-grade disinfectant.21
In her poster presentation, featured at the 2007 Association for Professionals in Infection Control and Epidemiology (APIC) annual conference, Spencer and her colleagues found that the product killed E. coli and S. aureus immediately upon contact and that the action was sustained over a 24-hour period. SilverClene24 is a disinfectant, fungicide, and virucide capable of killing bacteria in 30 seconds; and viruses and fungi in 10 minutes, according to Spencers study of the product. It also has a 24-hour active surface kill, and is proven effective against MRSA and VRE.
The product can be used on any number of objects and surfaces, and other advantages, they note, are decreased exposure to, and use of, chemical disinfectants and increased protection in areas underserved by housekeeping. We are using this spray in the pre-surgical unit, radiology suite, ambulatory care unit, recovery room and in public bathrooms, Spencer notes.
Emerging resistant pathogens will challenge healthcare facilities in the future even more than they do today, and prions, virus inactivation, biofilms and other forms of surface-adherent organisms, will continue to pose an extraordinary challenge to decontamination.12 It is for reasons such as these that the Hospital Infection Control Practices Advisory Committee (HICPAC) guidelines encourage continuing education on strategies to prevent the spread of contamination.22
One thought to leave with is that of resistance. Although resistance to such cleaning agents as biocides is generally not judged to be as critical as antibiotic resistance, scientific data supports the need for careful, proper use, and the avoidance of widespread application.12
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10. Baillie JK, et. al. Contamination of anaesthetic machines with pathogenic organisms. Anaesthesia. 2007 Dec;62(12):1257-61.
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14. Griffith CJ, et.al. The effectiveness of existing and modified cleaning regimens in a Welsh hospital. J Hosp Infect. 2007 Aug;66(4):352-9.
15. Eckstein BC, et. Al. Reduction of Clostridium Difficile and vancomycinresistant Enterococcus contamination of environmental surfaces after an intervention to improve cleaning methods. BMC Infect Dis. 2007 Jun 21;7:61.
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17. Hardy KJ. Rapid recontamination with MRSA of the environment of an intensive care unit after decontamination with hydrogen peroxide vapour. J Hosp Infect. 2007 Aug;66(4):360-8. Epub 2007 Jul 25.
18. Otter JA, et.al. Assessing the biological efficacy and rate of recontamination following hydrogen peroxide vapour decontamination. J Hosp Infect. 2007 Oct;67(2):182-8.
19. Boswell TC, Fox PC. Reduction in MRSA environmental contamination with a portable HEPA-filtration unit. J Hosp Infect. 2006 May;63(1):47-54.
20. Noyce JO, Michels H, Keevil CW. Potential use of copper surfaces to reduce survival of epidemic meticillin-resistant Staphylococcus aureus in the healthcare environment. J Hosp Infect. 2006 Jul;63(3):289-97.
21. Spencer, Maureen P., Cohen, Susan, McAllister, John. Microbiologic Evaluation of a Silver Antimicrobial Disinfectant Spray. Poster Presentation at the 34th Annual APIC Educational Conference and International Meeting. Abstract # 2-20. 2007.
22. Centers for Disease Control and Prevention. www.cdc.gov.