- Created on Tuesday, 22 July 2008 10:29
- Written by Staff
In the April, 2008 issue of Laundry Today, Dr. Nate Belkin authored an article entitled “An Ounce of Prevention” that mentioned issues with Methicillin Resistant Staphylococcus Aureus (MRSA), especially when considering healthcare laundering.
Dr. Belkin specifically cites two studies, one that indicates that MRSA has the ability to survive on healthcare textiles. The second determined that 40.2% of bed linen examined was contaminated with MRSA. With these citations, the article seems to imply that MRSA and similar bacteria are found on clean textiles, but that is not what the research showed. The first study, performed by Alice N. Neely and Mathew P. Maley, entitled “Survival of Enterococci and Staphylococci on Hospital Fabrics and Plastic” was performed by inoculating clean (sterile) textile samples with various solutions that contained the target bacteria, including MRSA. Samples were taken periodically and tested to see if the bacteria from the inoculations survived. The second study by S. Oie, S. Suenaga, A. Sawa & A. Kamiya was a test to determine whether MRSA was present on various hospital surfaces, including bed linens where patients diagnosed with MRSA infections were hospitalized. In other words both research studies were run on textiles that were contaminated with MRSA either in a laboratory setting or in actual hospital use with infected patients.
These citations while informative may be misleading. The article seems to imply to the unwary reader that MRSA will survive after the textiles have been laundered. But that is not the case, and the studies did not explore the effect of laundering on MRSA. What’s more it is well understood in the healthcare laundry industry that contaminated textiles should be handled in a precautionary manner to prevent potential disease transmission. The industry takes a series of precautions to make sure that contaminated textiles do not come in contact with clean textiles. We also take precautions to protect our laundry personnel from potential contamination. So these studies, although informative are not specifically applicable to the laundry industry.
After citing the potential contaminations with MRSA on hospital textiles, Dr. Belkin focused solely on the role of chlorine bleach as a chemical disinfectant in the laundry process. However, it is well known that the laundry process decontaminates textiles through the interaction of several factors, including:
- Dilution: Several water changes during the cleaning process physically remove and flush away bio-organisms. Mechanical action is also a factor to consider as bioburden is loosened from the fabric by proper mechanical action.
- Heat: Washing at elevated temperatures (>140ºF) deactivates much of the common bio-organisms.
- pH: High pH (>10.5) will "attack" or deactivate bio-organisms. In addition, large swings in pH, from neutral (7.0 - 8.0) in first flushes to alkaline (10.5 - 11.5) during the main wash cycles to acid (5.5 - 6.5) will adversely affect bio-organisms.
- Oxidation: Chlorine bleach or oxygen bleaches contribute to the bio-organism deactivation. Chlorine bleaches are well known to have excellent anti-bacterial and anti-viral efficacy. Oxygen bleach is considered to be somewhat less aggressive on bacteria and viruses, however, when combined with the other cleaning factors in a laundry formula, oxygen bleach is considered effective in deactivating residual microbes.
- Chemical Sanitizers or Bacteriostats: Some laundries as an extra precaution will use EPA registered products that will act as sanitizers in the final step of the laundry process.
- Drying: Drying at temperatures that exceed 180ºF on the fabric surface deactivate any potential remaining organisms.
There are numerous studies and articles that review the laundry decontamination process. It is important to state that chlorine bleaching is only one aspect of the process, and that the use of chlorine is not required to produce hygienically clean textiles. The Veteran’s Administration sponsored a research study that investigated the effect of low temperatures and chemical oxidation on the “hygienically clean” aspects of the laundering process used in their laundry facilities. This study is entitled “Killing of Fabric- Associated Bacteria in Hospital Laundry by Low Temperature Washing” (Blaser, et al., Journal of Infectious Diseases, Vol. 149, No. 1, Jan. 1984, 48-57). The article concluded that there was sufficient reduction of pathogenic bacteria, even in low temperature washing (22ºC, 72ºF). The study also noted that even with the elimination of chlorine bleach, adequate reduction in pathogens was observed when compared to traditional high temperature (71ºC, 160ºF) washing processes.
But the real question of MRSA raised by Dr. Belkin is also needs to be explored. His citations explain that MRSA can survive on contaminated textiles, and presumably may survive on the textiles that are returned to the laundry. To answer the MRSA question and how it relates to laundry, we first have to understand what MRSA is: it is a special strain of Staphylococcus aureus, or more simply "staph," which are bacteria that often live in the nose or on the skin of healthy people. When these bacteria penetrate the skin or invade other parts of the body, a staph infection may result. Staph bacteria that are resistant to the action of methicillin and related antibiotics are referred to as "methicillin-resistant staph aureus" or MRSA. MRSA is not only resistant to all penicillin-like antibiotics, but it is often resistant to many other types of antibiotics as well. Infections with MRSA can be costly and difficult to treat because of limited antibiotic options.
Methicillin and similar drugs are antibiotics. Antibiotics possess specific cellular targets within the organism such as a particular site on an enzyme. To use the analogy of a “lock and key” mechanism, antibiotics fit like a key into a lock to perform their purpose. As with a lock and key mechanism, minor changes in the lock will make the key useless; a single mutation in an organism can make it resistant to an antibiotic rendering the antibiotic ineffective.
Antimicrobial agents for use in hard surface disinfectants, sanitizers and skin antiseptics are not specific in their microbial attack mechanism. These products oxidize, denature or attack organisms in multiple ways. Unlike antibiotics, these products are used outside the human body (in the environment) at concentrations that are several thousand times higher than the concentrations of an antibiotic that is used in the body. Using the “lock and key” analogy, antimicrobials are equivalent to battering rams. If you were to use a battering ram to open a door, a small change in the door lock will not lessen the effect of the battering ram; a single mutation in an organism will not make it resistant to an antimicrobial.
In the laundry, bacteria are deactivated in several ways, as noted earlier. MRSA are NOT resistant to these chemical and physical “battering rams.” Typical healthcare laundering conditions effectively destroy MRSA and all bacteria to a level that will not cause human health issues. MRSA has no special mutation that protects the bacteria from deactivation by the typical factors found in a well designed healthcare laundry process. So it is not necessary to change time-proven laundry procedures because of MRSA. Dr. Belkin suggests with his article title that the laundry needs to take “An Ounce of Prevention.” I submit that a well designed laundry process, even with oxygen bleach yields much more that an ounce of protection; it generates “A Ton of Protection.”
Steven J. Tinker
Director, Research & Development
Gurtler Industries, Inc.
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