PROJECT 1 – Molecular Genetics

BACKGROUND

Staphylococcus aureus is a major human opportunistic pathogen responsible for a wide range of infections from mild- to life threatening conditions, with a high capacity for acquisition of antimicrobial resistance and virulence determinants. While methicillin resistant S. aureus (MRSA) have been a major cause of hospital associated multidrug resistant infections worldwide, methicillin-susceptible S. aureus (MSSA) infections have been increasingly reported, with an estimated of 84% rise in blood infections in Europe between 2005 and 2018. Like the European scenario, Portuguese hospitals have been identifying an increase in MSSA infections associated to serious illness. Previous studies showed that more than 60% of MSSA from hospital and community infections belonged to four clonal lineages (clonal complex (CC)30, CC5, CC45 and CC8) which, with the exception of CC5, are not commonly found among nosocomial MRSA population in the same settings. Thus, continued surveillance of the MSSA population circulating in hospitals is essential to understand the S. aureus epidemiology and infection dynamics. Additionally, knowledge of the clonal relationship and the presence of determinants of resistance to antibiotics and biocides among MSSA isolates responsible for nosocomial infections may contribute to the identification of dissemination routes and contribute to effective and targeted infection prevention guidelines.

OBJECTIVES

The major objectives will be the identification of antibiotic and biocide resistance profiles as well as the virulence potential of invasive MSSA isolates recovered in Portuguese hospitals between October 2022 and June 2023. In addition, molecular characterization, including whole genome analysis of the isolates, will provide information on major MSSA clonal lineages responsible for the increasing trend in invasive infections in Portugal.