MRSA is a resistant variation of the common bacterium Staphylococcus aureus. It has evolved an ability to survive treatment with most antibiotics. Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium responsible for difficult-to-treat infections in humans.

The organism is often sub-categorized as Community-Associated MRSA (CA-MRSA) or Health Care-Associated MRSA (HA-MRSA) although this distinction is complex. Some have defined CA-MRSA by criteria related to patients suffering from an MRSA infection while other authors have defined CA-MRSA by genetic characteristics of the bacteria themselves. The new CA-MRSA strains have rapidly spread in the United States to become the most common cause of cultured skin infections among individuals seeking medical care for these infections at emergency rooms in cities. These strains also commonly cause skin infections in athletes, jail and prison detainees, and soldiers.

Solution:
The overwhelming response in regards to the management and reduction in infection rates of these two pathogenic organisms were very basic; wash your hands regularly with an antimicrobial product and disinfect surfaces with a hard surface disinfectant–simple solutions to a very big problem.

BioScience Laboratories, Inc. has the capability of testing antimicrobial products, both topically applied antiseptics and hard surface disinfectants, for their efficacy against these organisms. To determine if a product is effective in killing these bacteria, standard in-vitro evaluations can be used to determine their efficacy. To take it a step further, one can evaluate their products’ efficacy in an IN-USE setting; that is, surrogate clinical trials on human volunteers. BSLI has recently been approved to conduct efficacy evaluations against C. diff and MRSA on Human Subjects. By working with an Institutional Review Board, BSLI has developed a Protocol to test the efficacy of topical antiseptic products on the skin. We feel that this type of testing will aid in the development of new novel antimicrobial products that can be used in day to day life as well as in hospital settings to help protect lives and reduce infections rates worldwide.

Kyle McGovern
Senior Account Executive

I will be the first to admit that I did not have the scientific background to understand the vast majority of the posters.  Also, as a marketing professional at first glance I could not see the focused, clear message that any poster was trying to deliver.  While some posters were created more professionally with better graphics, they all blended together for me.  It was not until I spent the time observing the poster viewing area that I was able to see how these posters are not only presenting relevant scientific data, they are also a valuable tool for collaboration, marketing, recruiting and sales.  I watched as scientists from leading industry companies and universities stopped in front of a poster, read every word and data table, reviewed every graph, and took notes on the methodology and results.  These posters provided insight to the scientist on a topic they were studying or wished they had the funding to study.  For some it even provided a leap forward in their research.

For the companies who sponsored the poster, conducted the research or testing, or supplied the testing material, it provided credibility to their scientific capabilities and data to set them apart.  And remarkably to me, it even provided leads, as scientists who were interested in the study dropped off the card.  For a company like ours, this could be a key product development contact and thus a sales lead.  For a products company this could be the lead for finding a new scientist interested sharing their research on a similar topic or maybe in working in their laboratory in the future.

I am sure that there is even more to be gained from displaying scientific posters than I saw at these two shows.  What value does your organization get from scientific posters displayed at industry events?

Jim Verzuh
Director of Marketing and Special Projects

Most of the methods employed by BioScience Laboratories, Inc. to evaluate antimicrobial efficacy of products involves quantitative techniques such as microbial counts.  The accuracy of these methods heavily depends upon inhibiting or neutralizing the antimicrobial activity of the product at specified times following exposure.  Recently, manufacturers of antimicrobial products are developing compounds or mixtures of compounds that have required additional attention to the inactivation of the antimicrobial activity of the product.  Publications have addressed how to perform and validate these neutralization procedures (see references).  

How does an investigator first decide on an appropriate method for inhibiting the antimicrobial activity of the product; in other words, what neutralizer system should be employed in efficacy testing?  Investigators have three basic neutralizer systems available to them; diluting to sub-inhibitory levels, chemical inactivation, or physically separating the product from the microorganism.  In some cases, a combination of these methods may be required to achieve inactivation.

Alcohol products are the most common type immediately neutralized by dilution.  Other products may require greater dilution before the inhibitory effects are eliminated.  In such situations, a chemical inactivator(s) can aid in reducing the dilution ratio required, and thereby, increasing the detection level of the product-testing for efficacy.  Dilution of the product may also be achieved, de facto, by performing an In Vivo neutralization assay (for those efficacy evaluations involving human volunteers).  In Vivo assays employs the application procedure to be used in the evaluation and the amount of product to be applied by the human volunteer.  Because the amount of product remaining on the skin of the subject post-application is much smaller than the volume of product used in an in-vitro neutralization procedure, the effects of neutralization by dilution are much greater.

Chemical inactivation is most often appropriate for neutralization of products that contain actives that are cationic or anionic in their activity.  Chemical compounds that have a stronger affinity for the active than does the target microorganism, but are themselves non-inhibitory, allow for design of a relatively simple neutralizer system. 

When dilution to sub-inhibitory levels and/or chemical inactivation fail to neutralize a product, physically separating the microorganism from the product is another, although cumbersome, alternative that requires use of a membrane filtration unit.  Diluting the product and using chemical inactivators as a rinsing solution can also be combined with membrane filtration.   Although membrane filtration in any combination is the most costly and time-consuming of the methods, it may be one’s only choice for certain antimicrobially active compounds. 

When performing antimicrobial efficacy evaluations, sponsors and investigators need to be made aware of the importance of determining a neutralizer system and the validation of the system.  Failure to neutralize the antimicrobial activity of a product will produce results that cause a sponsor to conclude that a product is efficacious when it is not.   We, here at BioScience Laboratories, Inc. have years of experience developing and validating systems for neutralizing a wide variety of antimicrobial products.  We fully understand the importance of producing results that demonstrate the actual efficacy of an antimicrobial product, and look forward to helping our clients in this endeavor. 

Christopher M. Beausoleil, CCRP

Senior Clinical Director

References

Sutton, Scott V.W. 1996. Neutralizer Evaluations as Control Experiments for Antimicrobial Efficacy Tests.  In: Handbook of Disinfectants and Antiseptics, J.M. Ascenzi, Ed. Marcel Dekker, New York. 300pp.

ASTM E 1054-08, Standard Test Methods for Evaluation of Inactivators of Antimicrobial Agents, ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, United States.

Beausoleil, Christopher M.  2003.  A Guide for Validation of Neutralizer Systems Used in Topical Antimicrobial Evaluations.  In: Handbook of Topical Antimicrobials, D.S. Paulson, Ed. Marcel Dekker, New York. 452 pp.

Several animal caliciviruses are known to be genetically closely related to human Norovirus, but only two have been studied for use as surrogates. These viruses are Feline Calicivirus (FCV) and Murine Norovirus (MNV).  FCV, a member of Vesivirus genus, can be readily propagated in cell cultures and has been extensively used as a surrogate for microbicide efficacy testing. As a respiratory pathogen, FCV is relatively sensitive to low pH treatment, which might represent a significant difference from the enteric human virus. MNV is the first cultivable animal virus representative of the Norovirus genus. This pathogen infects a wide range of laboratory mice and, like the human virus, is transmitted via the fecal-oral route. Nevertheless, MNV causes multiple clinical presentations in their natural host that are very different from those of human Norovirus. Despite the lack of experimental data on MNV and human Norovirus correlation, the murine pathogen is currently considered the most relevant surrogate, which means that manufacturers of microbicidal agents registered in the past based on FCV-testing will probably be required  to re-test against MNV.

New types of calicivirus are being discovered in human and animal populations, and some may have potential as surrogates. One example is the Tulane virus recently isolated from rhesus macaques, a host much closer evolutionarily to humans. It has been shown to exhibit the highest homology scores with the representatives of genus Norovirus in amino acid sequences of NTPase, Polymerase, and VP1 regions. From a practical point of view, establishment of the adequate surrogate will prevent recurrent evaluation with every newly discovered, but not experimentally validated virus, as well as undue financial pressure on manufacturers.

Potentially, the use of the closely related caliciviruses as surrogates might not be necessary. Viruses such as Poliovirus and Hepatitis A virus have been extensively studied for over five decades, and both are human enteric pathogens. Because of their evolutionary adaptation, the human enteric viruses may be more relevant with regard to chemical tolerance or environmental resistance than are viruses originated from distant hosts.

The U. S. Environmental Protection Agency (EPA) has posted its recommendations for the evaluation of antimicrobial pesticides for their efficacy versus Clostridium difficile.  These products include dilutable liquids or powders, ready-to-use formulations, spray products, or towelettes that are labeled for use to treat hard non-porous surfaces in healthcare settings where C. difficile spore contamination may occur.  The document presents guidance towards the recommended types/methods of testing, the number of product batches and carriers per test, the recommended/acceptable spore strains of Clostridium difficile, and product performance criteria.  Examples of allowable label claims for products meeting the acceptance criteria are also given.  To view the EPA’s recommendations visit http://www.epa.gov/oppad001/cdif-guidance.html.

Terri Eastman
Manager of In Vitro Laboratories