Occurrence of macrolide-lincosamide-streptogramin resistances among staphylococcal clinical isolates at a university medical center. Is false susceptibility to new macrolides and clindamycin a contemporary clinical and in vitro testing problem?

摘要: A total of 2189 staphylococcal strains at the University Iowa Hospitals and Clinics (Iowa City, IA) were initially screened to determine incidence constitutive (29.8%) potential inducible macrolide-lincosamide-streptogramin (MLS) resistance (11.3%). Staphylococcus haemolyticus S. epidermidis (62.5% 55.3%) showed highest resistance. hominis had (40.6%), while aureus lowest rate for both types. The overall ratio constitutive-inducible MLS was 4:1. Among speciated using Vitek System GPI card, there only a 69% species identification reproducibility, 78% accuracy versus reference method. random sample 105 spp. isolates with discordant macrolide (erythromycin resistant) lincosamide (clindamycin susceptible) susceptibility patterns tested against 16 antimicrobial agents by broth microdilution All erythromycin-resistant also resistant other 14-member macrolides azithromycin, all organisms remained susceptible clindamycin, rifampin, vancomycin, streptogramin compounds (RP59500 virginiamycin). Resistance teicoplanin identified among some oxacillin-resistant strains. Of isolates, 65 (62%) resistance, 28 (27%) noninducible, 12 (11%) either fully or drugs (Vitek interpretation errors). disk induction tests revealed two phenotypes: ML MLS. 95% an MLS-predominant pattern. In contrast, endemic did not demonstrate that is, efflux-mediated erythromycin resistance.(ABSTRACT TRUNCATED AT 250 WORDS)