RESUMEN
The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals is a major global public health concern. The current study sought to characterize 25 MRSA clinical isolates collected in a Tunisian hospital from December 2015 to September 2016, with the genetic lineages, virulence factors, and antibiotic resistance mechanisms determined for these isolates. Three spa-types were detected: t037 (23 isolates), t932, and t2235 (one isolate each). Isolates were ascribed to agr I (n = 20), agr II (n = 1), with four nontypeable isolates. Depending on sequence type (ST), the 25 MRSA isolates were assigned to two clonal complexes (CC8 and CC5), with a predominance of the lineage ST239-CC8 (n = 24; 96%). All isolates belonging to CC8 had the SCCmec type III, while the unique CC5 isolate had SCCmec type IV. Antimicrobial susceptibility testing revealed high levels of resistance to aminoglycosides, tetracycline, ciprofloxacin and rifampicin for the majority of isolates belonging to the ST239-CC8 lineage. The ST149-CC5 isolate was susceptible to non-ß-lactam antibiotics. One isolate harbored the tsst-1 gene (4%); however, lukS/LukF-PV, eta and etb genes were not detected. The MDR ST239-CC8 clone would seem to be widespread in this hospital. Therefore, a rigorous hygienic control system is urgently required.