Decontamination efficacy against Mycoplasma.

AIMS: Mycoplasma is minute bacteria that can be found ubiquitously in the environment and also in human, animal and plant tissues. In addition to their public health importance as aetiological agents of infections and possible association with certain cancers, mycoplasma is a major contamination concern in biotechnology. These bacterial cells are very small, can form biofilms and survive for extended periods of time when dried onto surfaces. Despite these concerns, there is little information concerning their resistance to currently used disinfection methods. The objective of this study was to evaluate commonly used biocidal treatments against three representative mycoplasma species. METHODS AND RESULTS: Mycoplasma was dried onto stainless steel coupons and exposed to decontamination products. All strains survived drying and any significant viability loss because of the test method (including neutralization), as demonstrated by a ≤0·5 log(10) for each tested species. The quaternary ammonium compound (QAC) tested presented poor efficacy, whereas 70% ethanol was fully efficient with complete inactivation after 5-min exposure. Alkaline cleaner formulations presented increasing efficacy when tested at 0·2, 0·4 and 0·8% concentrations, with complete kill observed at 0·8% of two products tested. Decontamination with vaporized (gaseous) hydrogen peroxide (VHP) was very efficient at concentrations used for room and small enclosures decontamination (180-1200 ppm with various time exposures), as well as for device sterilization applications. CONCLUSIONS: Ethanol and alkaline detergent formulations were particularly efficient against mycoplasma, but a QAC formulation was not. VHP in room disinfection and device sterilization applications was effective against all mycoplasma species tested. SIGNIFICANCE AND IMPACT OF THE STUDY: Mycoplasma can provide resistance to environmental factors (such as drying) and disinfectants. Further studies are required to confirm the effectiveness of other disinfectants and the mechanisms of mycoplasma resistance.

Disinfection efficacy against parvoviruses compared with reference viruses.

Some virus species can resist harsh environmental conditions, surviving on surfaces for long periods with the possibility of being transmitted to susceptible hosts. Studies are limited on the efficacy of disinfectants against viruses dried onto surfaces, in particular, with the identification of new pathogenic non-enveloped viruses that are expected to have high resistance to disinfection, such as parvoviruses. In this study a range of commonly used biocides, including heat, was tested against porcine parvovirus (PPV), minute virus of mice (a parvovirus), poliovirus type 1, adenovirus type 5, and vaccinia virus dried onto surfaces. PPV was the most resistant species identified, since many biocides generally considered as effective against non-enveloped viruses and used for high level disinfection demonstrated limited activity. Ethanol had poor activity against all non-enveloped viruses. Effectiveness against these viruses may be important in preventing nosocomial transmission of emerging pathogenic species such as bocavirus and other parvoviruses. This work confirms the need to validate disinfection products against viruses dried onto surfaces and demonstrates that PPV is a particularly resistant surrogate.