First detection of methicillin-susceptible Staphylococcus aureus clonal complex CC398 carrying ermT in processed foods from northeastern Argentina

Methicillin-susceptible Staphylococcus aureus (MSSA) clonal complex CC398 carrying ermT has emerged as a prevalent lineage in human bloodstream infections in South America. We analyzed 77 S. aureus isolates from processed foods in Misiones and northern Corrientes, Argentina, from a retrospective (2009–2010, n = 36) and a prospective cohort (2020–2024, n = 41). Antimicrobial susceptibility was determined by disk diffusion and the D -test. Based on a two-step phenotypic selection (methicillin susceptibility and the D -test), 20 MSSA-iMLSb positive isolates were identified, of which 14 were analyzed by PCR for the presence of the sau1-hsdS1 and ermT genes. All 14 isolates tested positive for both markers, consistent with their assignment to CC398. A marked increase in the iMLSb phenotype was observed between cohorts: 2.8% (1/36) in 2009–2010 versus 46% (19/41) in 2020–2024. This is the first report of CC398-MSSA- ermT + in processed foods from northeastern Argentina, with evidence of its circulation dating back to at least 2009–2010.