The Committee for the Surveillance of Nosocomial Infections (SPIN), in collaboration with the Committee on Nosocomial Infections of Quebec (CINQ), has initiated a mandatory bacteremia surveillance program in Staphylococcus (S.) aureus in 2006. Analysis of the results of this surveillance suggested that a significant proportion of bacteremias S. aureus resistant to methicillin (MRSA) was not nosocomial acquisition (Galarneau et al. 2008). Therefore, the CINQ considered it important to study the molecular profile of MRSA strains isolated from blood cultures in Quebec, regardless of the category of attribution, nosocomial or community, of the bacteremia.
The Ministry of Health and Social Services has entrusted the Laboratoire de santé publique du Québec (LSPQ) with the mandate to study the 2019-2020 molecular profile of MRSA strains for a fifth period of one year. This summary presents the results of the laboratory analyzes of this surveillance. The characterization of the strains includes their antibiogram, the determination of the epidemic type (MRSA-AH [acquisition hospitalière] versus SARM-AC [acquisition communautaire]) by gene sequencing spa as well as the detection of the Panton Valentine Leukocidin (PVL) toxin gene by the nucleic acid amplification technique (NAAT).
The 2019-2020 surveillance of MRSA strains isolated from bacteremia made it possible to follow MRSA trends in Quebec for a fifth period in the last 10 years. It confirms the drastic drop in HA-MRSA, thus reflecting the effectiveness of the means of intervention to fight nosocomial infections implemented since 2005 in all hospital sites in Quebec. It should also be noted that high sensitivity rates have been maintained for the main antibiotics of clinical interest.
On the other hand, the 2019-2020 surveillance describes a spectacular increase (> 145%) in the proportion of CA-MRSA strains, which represented 46.5% of the strains isolated in Quebec. It also confirms an increase in CA-MRSA strains not expressing the PVL toxin gene. A better understanding of the risk factors associated with the emergence of community-acquired MRSA could contribute to the implementation of targeted prevention strategies like those implemented for the prevention and control of nosocomial infections in Quebec. .
The hospital laboratories obtained an analysis report for each strain submitted, including the results of typing, sensitivity to antibiotics and for the presence of the PVL toxin. Due to the COVID-19 pandemic, the report including analyzes of epidemiological data associated with the surveillance of these MRSA strains has not been completed.