Summary

According to the Institut national de santé publique du Québec (INSPQ), nosocomial infections are a leading cause of healthcare complications, with impacts that include increased mortality and morbidity, prolonged hospitalization and a sharp spike in healthcare costs. These infections are the fourth cause of mortality in Canada and account for many occupational injuries (Raka and coll. 2006). Although considerable effort has been made in the field to contain this problem, nosocomial infections continue to exist and are becoming more complex: antibiotic resistance, more virulent strains, etc. The risk incurred by staff working in healthcare settings must be reviewed and redefined on the basis of new molecular approaches to bioaerosol analysis. There have been few serious investigations of this vector (Beggs, 2003; Tellier, 2009; Lindsley and coll. 2010). Nonetheless, healthcare staff are in frequent contact with infectious biological agents in the air and the environment.

The purpose of this exploratory project was, first, to validate the implementation of methodologies for better detection of viruses in healthcare settings and, secondly, to assess whether these methodologies and the preliminary data obtained can be applied to a larger-scale study on this research theme.

Two different air sampling techniques were applied in the field, one using an experimental sampler, NIOSH 251, and the other Coriolisµ® manufactured by Bertin Technologies. After the samples were treated to concentrate them, ribonucleic acid (RNA) was extracted. Specific targets such as influenza A and B, as well as norovirus G1 and G2 were detected through real-time polymerase chain reaction (real-time quantitative PCR). To assess norovirus resistance to aerosolization, we used a cell culture and murine norovirus model. Aerosols were generated in an environmental chamber and then sampled. The total viral load of the samples was evaluated through real-time quantitative PCR and the viability of the viruses through cell culture.

The influenza viruses were able to be detected in emergency room air using sentinel samplings. These viruses were also detected in a patient room and the adjacent corridor. We also detected norovirus in the air of several patient rooms (hospital and long-term care facility [CHSLD]), in the adjacent corridors, at the nurses’ station and on surfaces, suggesting underestimated and undocumented occupational exposure. In the environmental chamber tests, we showed that infectious viral particles could be collected with air samplers, suggesting norovirus resistance to aerosolization stress.