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

Nerea C Rosales-González; Margarita González-Martín; Idris Nasir Abdullahi; María Teresa Tejedor-Junco; Javier Latorre-Fernández; Carmen Torres

doi:10.1016/j.resmic.2023.104176

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

Res Microbiol. 2023 Dec 21:104176. doi: 10.1016/j.resmic.2023.104176. Online ahead of print.

Authors

Nerea C Rosales-González¹, Margarita González-Martín², Idris Nasir Abdullahi³, María Teresa Tejedor-Junco⁴, Javier Latorre-Fernández³, Carmen Torres³

Affiliations

¹ Servicio de Medicina Interna, Hospital Universitario de Gran Canaria Dr Negrín, Spain.
² Research Institute of Biomedical and Health Sciences, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Canary Islands, Spain. Electronic address: margaritarosa.gonzalez@ulpgc.es.
³ Area of Biochemistry and Molecular Biology, One Health-UR Research Group, University of La Rioja, 26006 Logroño, Spain.
⁴ Research Institute of Biomedical and Health Sciences, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Canary Islands, Spain.

PMID: 38141795
DOI: 10.1016/j.resmic.2023.104176

Abstract

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.

Keywords: Antimicrobial resistance; MSSA-CC398; Medical students; Nasal carriage; Nosocomial MRSA.