Fluoroquinolone Resistance in Penicillin-resistant Streptococcus pneumoniae Clones, Spain

摘要

Among 2,882 Streptococcus pneumoniae sent to theSpanish Reference Laboratory during 2002, 75 (2.6)were ciprofloxacin-resistant. Resistance was associatedwith older patients (3.9 in adults and 7.2 in patients ≥65years of age), with isolation from noninvasive sites (4.3vs. 1.0), and with penicillin and macrolide resistance.Among 14 low-level resistant (MIC 4–8 μg/mL) strains, 1had a fluoroquinolone efflux phenotype, and 13 showedsingle ParC changes. The 61 high-level ciprofloxacin-resistant (MIC ≥16 μg/mL) strains showed either two orthree changes at ParC, ParE, and GyrA. Resistance wasacquired either by point mutation (70 strains) or by recom-bination with viridans streptococci (4 strains) at the topoi-somerase II genes. Although 36 pulsed-field gelelectrophoresis patterns were observed, 5 internationalmultiresistant clones (Spain23F-1, Spain6B-2, Spain9V-3,Spain14-5 and Sweden15A-25) accounted for 35 (46.7) ofthe ciprofloxacin-resistant strains. Continuous surveillanceis needed to prevent the dissemination of these clones