Among 155 clinical respiratory isolates of Haemophilus influenzae in Korea, 6 (3.9%) isolates had reduced levofloxacin susceptibility (MICs > or = 0.5 microg/mL). These six isolates had no significant quinolone resistance-determining region (QRDR) mutations in gyrA, gyrB, parC, or parE. This phenomenon suggests that neither evolution nor spread of any significant QRDRs mutations in clinical isolates occurred in Korea. Therefore, continued surveillance is necessary to observe the evolution of antibiotic-resistance and take measures to avoid the spread of drug-resistant clones.
Anti-Bacterial Agents/*pharmacology ; DNA Gyrase/*genetics ; DNA Topoisomerases, Type II/*genetics ; Haemophilus influenzae/*drug effects/pathogenicity ; Korea ; Microbial Sensitivity Tests ; Mutation ; Ofloxacin/*pharmacology

Among 155 clinical respiratory isolates of Haemophilus influenzae in Korea, 6 (3.9%) isolates had reduced levofloxacin susceptibility (MICs > or = 0.5 microg/mL). These six isolates had no significant quinolone resistance-determining region (QRDR) mutations in gyrA, gyrB, parC, or parE. This phenomenon suggests that neither evolution nor spread of any significant QRDRs mutations in clinical isolates occurred in Korea. Therefore, continued surveillance is necessary to observe the evolution of antibiotic-resistance and take measures to avoid the spread of drug-resistant clones.
Anti-Bacterial Agents/*pharmacology ; DNA Gyrase/*genetics ; DNA Topoisomerases, Type II/*genetics ; Haemophilus influenzae/*drug effects/pathogenicity ; Korea ; Microbial Sensitivity Tests ; Mutation ; Ofloxacin/*pharmacology