Applied and environmental microbiology
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Appl. Environ. Microbiol. · May 2010
Effects of air temperature and relative humidity on coronavirus survival on surfaces.
Assessment of the risks posed by severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) on surfaces requires data on survival of this virus on environmental surfaces and on how survival is affected by environmental variables, such as air temperature (AT) and relative humidity (RH). The use of surrogate viruses has the potential to overcome the challenges of working with SARS-CoV and to increase the available data on coronavirus survival on surfaces. Two potential surrogates were evaluated in this study; transmissible gastroenteritis virus (TGEV) and mouse hepatitis virus (MHV) were used to determine effects of AT and RH on the survival of coronaviruses on stainless steel. ⋯ There was also evidence of an interaction between AT and RH. The results show that when high numbers of viruses are deposited, TGEV and MHV may survive for days on surfaces at ATs and RHs typical of indoor environments. TGEV and MHV could serve as conservative surrogates for modeling exposure, the risk of transmission, and control measures for pathogenic enveloped viruses, such as SARS-CoV and influenza virus, on health care surfaces.
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Appl. Environ. Microbiol. · May 2010
Inhibitory effect of biocides on the viable masses and matrices of Staphylococcus aureus and Pseudomonas aeruginosa biofilms.
Bacteria and matrix are essential for the development of biofilms, and assays should therefore target both components. The current European guidelines for biocidal efficacy testing are not adequate for sessile microorganisms; hence, alternative discriminatory test protocols should be used. The activities of a broad range of biocides on Staphylococcus aureus and Pseudomonas aeruginosa biofilms were evaluated using such in vitro assays. ⋯ This study clearly demonstrated that despite their aspecific mechanisms of action, most biocides were active only against biofilm bacteria, leaving the matrix undisturbed. Only hydrogen peroxide and sodium hypochlorite were active on both the biofilm matrix and the viable mass, making them the better antibiofilm agents. In addition, this study emphasizes the need for updated and standardized guidelines for biofilm susceptibility testing of biocides.