[Phenotype and genotype of antimicrobial resistance on nasal Staphylococcus aureus isolates from healthy people].

OBJECTIVE: To investigate the antimicrobial susceptibility and molecular nature related to the resistance on macrolides from nasal Staphylococcus (S.) aureus isolates among healthy people. METHODS: A total of 100 S. aureus isolates collected from 2009 to 2011 were tested for antimicrobial susceptibility by E-test. Double disc test (D-test) was used to detect the inducible clindamycin resistance. All S. aureus isolates were characterized by spa typing. Macrolides resistance genes were detected and compared with isolates that were collected clinically or from the livestock. RESULTS: High resistance rates on erythromycin or clindamycin was noticed, with 52% and 27%, respectively. Inducible clindamycin resistance was identified in 29 of the 100 (29%) isolates. In total, the 100 isolates were assigned to 35 spa types. The most common spa types were found to be t189, t571, t002, t796, t437, t034 and t701, that accounted for 51.0% of all the isolates. erm (C) (57.7%) and erm (B) (34.6%) were found as the dominant genes in 52 S. aureus isolates from healthy people. On the other hand, erm (A) and erm (C) were identified in 95.0% S. aureus isolates from patients and all the livestock, respectively. CONCLUSION: erm (C) and erm (B) carrying S. aureus strains were circulating in healthy people and these genes were distributed in different S. aureus clones.