Prevalence, Characteristics, and Molecular Epidemiology of Macrolide and Fluoroquinolone Resistance in Clinical Isolates of Streptococcus pneumoniae at Five Tertiary-Care Hospitals in Korea

The genes erm (B), mef (A), and both erm (B) and mef (A) were identified in 42.6, 10.1, and 47.3%, respectively, of the erythromycin-resistant Streptococcus pneumoniae isolates. Of the strains, 3.8% were nonsusceptible to levofloxacin and had 1 to 6 amino acid changes in the quinolone resistance-determining region, including a new mutation, Asn94Ser, in the product of parC . Levofloxacin with reserpine was highly specific for efflux screening.