Survival of enveloped and non-enveloped viruses on surfaces compared with other micro-organisms and impact of suboptimal disinfectant exposure

Survival of enveloped and non-enveloped viruses was compared with that of bacteria, yeasts and mycobacteria when dried on the surface of polyvinyl chloride test carriers in the presence or absence of an organic matrix. The efficacy of glutaraldehyde and accelerated hydrogen peroxide (AHP) disinfectants was evaluated. Reovirus, a non-enveloped virus, persisted and had a RF of 2 after 30 days whereas Enterococcus faecalis had an RF of 4 over the same time period. The other test organisms (Sindbis virus, Pseudomonas aeruginosa, Mycobacterium chelonae and Candida albicans) had variable survivals but none survived as long as 30 days. Both glutaraldehyde and AHP were effective at manufactures' recommended dilutions for high-level disinfection. However, only 7% AHP eliminated a glutaraldehyde-resistant strain of M. chelonae. Breakthrough survival was detected at 0.1% glutaraldehyde and 0.05% AHP for all organisms tested. Our data emphasise the need for effective cleaning and disinfection in nosocomial settings to prevent pathogen transmission.

Allen Denver Russell Memorial Lecture, 2006

Microbial pathogens continue as major threats to health. Indeed, many ongoing societal changes are enhancing our vulnerability and exposure to several frank and opportunistic pathogens. This, together with rampant antimicrobial resistance and reduced prospects for newer drugs and vaccines, is forcing a higher reliance on microbiocides in infection prevention and control. That this reliance may not be well-founded becomes apparent from a closer look at current ways of testing and registering microbiocides, their label claims as well as human and environmental safety of certain widely used microbicidal chemicals. Many methods to test microbiocides for registration are flawed and/or entail test conditions irrelevant to field use. Pathogens listed on product labels may not be among those amenable to interruption through microbiocide use. The wide variations and discrepancies in existing national/regional regulations for registering microbiocides for sale stifle innovation. This is a critical look at the above-mentioned issues with emphasis on chemicals meant for use on environmental surfaces and medical devices. It highlights better ways to test microbiocides and to attain global harmonization of testing and product registration. It also details the known and potential dangers of microbiocide use and what to consider in choosing such formulations for optimal safety and effectiveness. End users are advised to be more critical and prudent in the selection and application of microbicidal chemicals, manufacturers are encouraged to explore infection control products and technologies that are safer in the workplace and for the environment, and regulators are urged to review and update the requirements and procedures for premarket review of microbiocide efficacy data and label claims. Independent investigations are also urgently needed to document the proportion of nosocomial infections that would be amenable to prevention through chemical disinfection of environmental surfaces.

Broad-spectrum microbicidal activity, toxicologic assessment, and materials compatibility of a new generation of accelerated hydrogen peroxide-based environmental surface disinfectant

Background

Concerns on human and environmental safety and label claims of many microbicides point to the need for safer, faster acting, and broad-spectrum substitutes. ACCEL TB, a 0.5% accelerated H₂O₂ (AHP)-based disinfectant described here, is a potential candidate.

Methods

ACCEL TB was tested for its broad-spectrum microbicidal activity, safety and materials compatibility using internationally accepted protocols. Activity against bacteria (Staphylococcus aureus, Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, vancomycin-resistant Enterococcus faecalis, methicillin-resistant Staphylococcus aureus, and Salmonella choleraesuis) was tested with the AOAC use-dilution method and the first tier of a quantitative carrier test (QCT-1). Mycobactericidal activity was tested against Mycobacterium bovis and Mycobacterium terrae using a quantitative suspension test (QST) and QCT-1, respectively. Fungicidal activity (Trichophyton mentagrophytes) was determined with the AOAC test and QCT-1. Activity against several enveloped and nonenveloped viruses was evaluated using the American Society for Testing and Materials (ASTM) method No. E-1053. Sanitizing action was tested against 7 types of vegetative bacteria with method No. DIS/TSS-10. All microbicidal tests contained an added soil load; in all AOAC tests, it was 5% fetal bovine serum, and, in QCT-1, a mixture of 3 types of proteins in phosphate buffer was used instead. The methods to test for acute oral, dermal, inhalation toxicities, and dermal and eye irritation as well as skin sensitization complied with the requirements of the Organization for Economic Cooperation and Development and the US Environmental Protection Agency (OPPTS 870). Standard methods were also used to test compatibility with metals and plastics.

Results

At 20°C, the full-strength product was bactericidal and virucidal in 1 minute and mycobactericidal and fungicidal in 5 minutes. It was nonirritating to skin and eyes. The acute oral LD₅₀ (lethal dose 50%) was >5000 mg/kg. It was compatible with 12 types of plastic and 3 out of 4 metals.

Conclusion

The tested formulation showed a high safety and materials compatibility profile in addition to being a fast acting, intermediate-level disinfectant.