Prevalence, antimicrobial resistance, and genetic lineages of nasal Staphylococcus aureus among medical students at a Spanish University: detection of the MSSA-CC398-IEC-type-C subclade

• Published in: Research in microbiology 2024-05, Vol.175 (4), p.104176, Article 104176
• Main Authors: Rosales-González, Nerea C, González-Martín, Margarita, Abdullahi, Idris Nasir, Tejedor-Junco, María Teresa, Latorre-Fernández, Javier, Torres, Carmen
• Format: Article
• Language: English
• Subjects: Adult; Anti-Bacterial Agents - pharmacology; Bacterial Proteins - genetics; Carrier State - epidemiology; Carrier State - microbiology; Cross-Sectional Studies; Drug Resistance, Bacterial - genetics; Drug Resistance, Multiple, Bacterial - genetics; Female; Genotype; Humans; Male; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - drug effects; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Microbial Sensitivity Tests; Penicillin-Binding Proteins - genetics; Prevalence; Spain - epidemiology; Staphylococcal Infections - epidemiology; Staphylococcal Infections - microbiology; Staphylococcus aureus - classification; Staphylococcus aureus - drug effects; Staphylococcus aureus - genetics; Staphylococcus aureus - isolation & purification; Students, Medical; Universities; Young Adult
• ISSN: 0923-2508; 1769-7123; 1769-7123
• DOI: 10.1016/j.resmic.2023.104176

Medical students could be a potential source of Staphylococcus aureus transmission to patients. This cross-sectional study involved samples collected from both nasal nostrils. Samples were processed for S. aureus recovery; the antimicrobial resistance (AMR) phenotype was determined by disc diffusion assays and the spa types and AMR genotypes by PCR/sequencing. A structured questionnaire was administered to students to collate data related to potential risk factors of nasal colonization. Ninety-eight students were included, 50 % were colonized by S. aureus and 12.2 % by MRSA. The mecA gene was detected in all MRSA isolates. The MSSA-CC398-IEC-type C lineage was found among 16.3 % of nasal carriers, of which t571 was the predominant spa-type. MRSA isolates were ascribed to spa types t2226 (CC5, 12 isolates) and t3444 (new spa type, 1 isolate). All MRSA were multi-drug resistant and MSSA were predominantly resistant to erythromycin-clindamycin (inducible-type, mediated by ermT gene). High rates of S. aureus and MRSA nasal carriages were observed in this study. The predominance of the CC398 lineage among MSSA (emergent invasive lineage) represent a relevant finding of public health concern. The role of medical students as potential source of MRSA and MSSA-CC398 transmissions in hospital and community needs to be elucidated in detail.