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Mohamed Rhouma,1 William Thériault,1 Nassima Rabhi,1 Caroline Duchaine,2 Sylvain Quessy,1 Philippe Fravalo11Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2, Canada; 2Department of Biochemistry, Microbiology and Bioinformatics, Faculty of Science and Engineering, Université Laval, Québec, QC G1V 4G5, Canada Colistin is considered one of the last-resort antibiotics used for the treatment of infections caused by multidrug-resistant Gram-negative bacteria (MDR-GNB) in humans.1 This antibiotic is classified by the World Health Organization, among the category of the Highest Priority Critically Important Antimicrobials for human medicine.2 In this regard, the global dissemination of plasmid-mediated colistin resistance, conferred by themobile colistin resistance (mcr) genes, has raised serious concern among physicians and scientists worldwide.2 On the other hand, colistin has been widely used in food animals in many countries either for disease therapy, prophylaxis or for growth promotion.3 Many studies reported a high prevalence of mcr genes on bacterial isolates from animals' origin compared to humans, and consequently animals, particularly pig production, were pointed out as the greatest cause of bacterial colistin resistance spread.1 In pigs, mcr genes were isolated mainly from colistin resistant E. coli, Salmonella and Klebsiella isolates, with mcr-1 gene being themost frequently identified gene among the eight types of mcr genes currently described.1 Among other Gram-negative bacteria (GNB) of pig origin, mcr genes were identified in Moraxella spp.,4 and in Aeromonas hydrophila,5 enforcing the interest to consider the mcr presence at the microbiota level. In Canada, although colistin is not approved for use in veterinarymedicine, it was sometimes used in pigs according to special precautions for the oral treatment of digestive infections caused by GNB.1 Nevertheless, mcr-1 gene has been identified in E. coli isolated from humans, as well as from lean ground beef in Canada.6 However, to the best of our knowledge, mcr genes have never been identified in animals at the farm level in Canada. Here we report he screening of fecal samples obtained from one Canadian commercial pig farm, to determine the prevalence over the growing period of mcr-1 and mcr-2 genes in the fecal microbiota of pigs. Colistin has never been used in this farm. However, tiamulin and chlortetracycline were used in the post-weaning period and salinomycin as well as narasin were used during the growing phase.

The question of whether there is or was life on Mars has been one of the most pivotal since Schiaparellis' telescopic observations of the red planet. With the advent of the space age, this question can be addressed directly by exploring the surface of Mars and by bringing samples to Earth for analysis. The latter, however, is not free of problems. Life can be found virtually everywhere on Earth. Hence the potential for contaminating the Mars samples and compromising their scientific integrity is not negligible. Conversely, if life is present in samples from Mars, this may represent a potential source of extraterrestrial biological contamination for Earth. A range of measures and policies, collectively termed 'planetary protection', are employed to minimise risks and thereby prevent undesirable consequences for the terrestrial biosphere. This report documents discussions and conclusions from a workshop held in 2012, which followed a public conference focused on current capabilities for performing life-detection studies on Mars samples. The workshop focused on the evaluation of Mars samples that would maximise scientific productivity and inform decision making in the context of planetary protection. Workshop participants developed a strong consensus that the same measurements could be employed to effectively inform both science and planetary protection, when applied in the context of two competing hypotheses: 1) that there is no detectable life in the samples; or 2) that there is martian life in the samples. Participants then outlined a sequence for sample processing and defined analytical methods that would test these hypotheses. They also identified critical developments to enable the analysis of samples from Mars. © 2014 The Committee on Space Research (COSPAR).

Pig buildings produce and emit large amounts of airborne contaminants into the environment. Odors, gases, dust, and bioaerosols are responsible for the emergence of infectious, toxic, and inflammatory diseases diagnosed in animals, workers, and surrounding communities. There is therefore a need for better characterization and mitigation of airborne contaminants in commercial pig buildings. Bench-scale pig buildings could be used for the development and evaluation of reduction strategies for airborne contaminants in a timely and cost-effective manner before scaling them up for commercial use. Six bench-scale pig buildings were designed for growing animals (commercial diet and fully slatted concrete floor) and for producing odors, gases, dust, and bioaerosols from various sources (e.g., feed, manure) and animal activities. The validation of the six identical, environmentally controlled, independently ventilated and sealed bench-scale pig buildings (7.1 m³, 42 air changes per hour) is reported here. The validation implied inter-building and longitudinal (between week) comparisons of concentrations of airborne contaminants. Environmental conditions, methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O), ammonia (NH3), and airborne microorganisms (total bacteria and archaea, Clostridium perfringens, Enterococcus spp., and Escherichia coli) were monitored for seven weeks in the six bench-scale pig buildings. The experiment was repeated three times. From week to week, data analysis showed that environmental conditions, gases, odors, and airborne microbial concentrations were non-statistically different between buildings. By the end of the seven-week experiment, concentrations of N2O, NH3, Enterococcus, E. coli, and archaea were higher than during week 1 in all buildings (p < 0.05). Airborne gases, odors, and microbial concentrations were equivalent to those found during the Canadian summer in commercial finishing pig buildings. In conclusion, the designed bench-scale pig buildings may serve for multi-replicate experiments and for studying airborne contaminants found in commercial pig buildings. [ABSTRACT FROM AUTHOR]

Subway systems worldwide transport more than 100 million people daily; therefore, air quality on station platforms and inside trains is an important urban air pollution issue. We examined the microbiological composition and abundance in space and time of bioaerosols collected in the Barcelona subway system during a cold period. Quantitative PCR was used to quantify total bacteria, Aspergillus fumigatus, influenza A and B, and rhinoviruses. Multitag 454 pyrosequencing of the 16S rRNA gene was used to assess bacterial community composition and biodiversity. The results showed low bioaerosol concentrations regarding the targeted microorganisms, although the bacterial bioburden was rather high (104 bacteria/m3). Airborne bacterial communities presented a high degree of overlap among the different subway environments sampled (inside trains, platforms, and lobbies) and were dominated by a few widespread taxa, with Methylobacterium being the most abundant genus. Human-related microbiota in sequence dataset and ascribed to potentially pathogenic bacteria were found in low proportion (maximum values below 2% of sequence readings) and evenly detected. Hence, no important biological exposure marker was detected in any of the sampled environments. Overall, we found that commuters are not the main source of bioaerosols in the Barcelona subway system. [ABSTRACT FROM AUTHOR]