Genomic Epidemiology of Methicillin-Resistant Staphylococcus aureus Infections Prior to and During the COVID-19 Pandemic

The World Health Organization has declared antimicrobial resistance a major global health threat and lists methicillin-resistant Staphylococcus aureus (MRSA) as a priority pathogen. MRSA can cause severe infections and spreads by direct contact with infected individuals or contaminated surfaces or medical devices. Originally, MRSA mostly affected people in hospitals, but is now also common in the community. Hospital and community-associated MRSA strains differ, where hospital strains are resistant to more antibiotics and community strains can spread more easily and cause severe skin and soft tissue infections. However, in recent years, these strains have been found in both settings. This is concerning because MRSA can easily pick up beneficial genes from other bacteria, and the movement of these strains between settings poses the risk of more deadly MRSA infections that are highly resistant to antibiotics and easily spread. In Canada, MRSA is not regularly tracked outside of healthcare settings, and its genetic analysis has not been done on a population level. Our project aims to study MRSA genetics by analyzing samples collected from infected individuals across Ontario, including both hospital- and community-associated MRSA. We believe the COVID-19 pandemic and related public health measures may have affected the types of MRSA strains that are spread in the population. By studying samples collected before and during the pandemic, we can better understand MRSA strains and identify genetic features that may help some of them survive antibiotic treatment and cause more serious disease. This information is critical for targeted interventions to stop the spread of MRSA. This project will provide a foundation for MRSA genetic studies in the post-pandemic era that can be used across Canada.