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The term 'Chlamydia-like organisms' encompasses obligate intracellular bacterial species phylogenetically close to Chlamydiaceae. Most are associated with free-living amoebae, and several could be responsible for respiratory tract infections and abortion in human and animals. Despite increasing concern about their pathogenic role, the prevalence, biodiversity and ecology of Chlamydia-related bacteria still remain largely unknown. In this study, six members of the Chlamydiales were tested, including Parachlamydia acanthamoebae (two different strains), Protochlamydia naegleriophila, Waddlia chondrophila, Criblamydia sequanensis and Chlamydia trachomatis as a reference. Intracellular growth was tested in 11 different Acanthamoeba strains, demonstrating significant differences in host susceptibilities to infection depending on strains investigated. Survival of host-free bacteria in suspension or dried onto surfaces was also explored, demonstrating that Chlamydia-like organisms present better survival capacity than C. trachomatis. Longer survival times were observed for bacteria suspended in rich culture medium, with survivors being detected after 10 weeks incubation. We also tested susceptibility of host-free Chlamydia-like organisms to several disinfection treatments. Each chemical biocide tested reduced viability of host-free Chlamydia by more than 4 logs. Conversely, all Chlamydia-like organisms tested resisted exposure at 55 °C for 10 min, while C. trachomatis was completely inactivated.

Some virus species can resist surprisingly harsh environmental conditions, being able to survive on surfaces for long periods and often presenting high resistance to disinfection. Viruses can be transmitted to susceptible hosts via these contaminated surfaces. This is a major concern not only in healthcare and research but also in manufacturing settings, with recent occurrences reporting viral contamination of non-human cells used to produce therapeutic enzymes in bioreactors. Consequently, a need to validate the virucidal efficacy of products used to clean and decontaminate surfaces in these facilities exists. In this study we tested two alkaline cleaners (CIP-100 and ProKlenz-One), two liquid disinfectants (SporKlenz and a peracetic-based formulation), and a gaseous hydrogen peroxide-based aerial decontamination process for their capacity to inactivate several viruses, including parvoviruses in the presence of organic soils. We demonstrate that these decontamination methods offer virucidal efficacy and can consequently ensure a very high level of protection against viral contamination.

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 log10 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.

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