title: Phenotypic and genotypic analysis of levofloxacin-resistant clinical isolates of Streptococcus pneumoniae collected in 13 countries during 1999-2000.
abstract: During 1999-2000, 5015 isolates were collected from 13 countries and tested against levofloxacin. Overall, levofloxacin resistance minimum inhibitory concentration (MIC>or =8 mg/l) was found in 40 isolates (0.8%). The highest resistance rates were in Hong Kong (8.0%), China (3.3%) and Spain (1.6%). Levofloxacin retained an MIC(90) of 1 mg/l in all countries. Pulsed-field gel electrophoresis analysis of resistant isolates demonstrated the presence of clones in countries where levofloxacin resistance exceeded 1%, suggesting that the elevated resistance rates could result from resistant clones within participating hospitals. DNA-sequence analysis of the quinolone-resistance-determining regions of gyrA, gyrB, parC and parE genes showed that the most common mutations were in GyrA (Ser81Phe), ParC (Ser79Phe, Lys137Asn) and ParE (Ile460Val), accounting for 40% of the isolates tested. Levofloxacin-resistant isolates were generally non-susceptible to other fluoroquinolones tested. Future studies to characterise resistant isolates by other molecular methods may ensure that the appropriate counter-measures can be taken to control the spread of resistant isolates.
authors.affiliation: Focus Technologies, Inc., 13665 Dulles Technology Drive, Herndon, VA 20171, USA. icritchley@focusanswers.com
authors.forename: Ian A
authors.initials: IA
authors.lastname: Critchley
authors.forename: Renée S
authors.initials: RS
authors.lastname: Blosser-Middleton
authors.forename: Mark E
authors.initials: ME
authors.lastname: Jones
authors.forename: James A
authors.initials: JA
authors.lastname: Karlowsky
authors.forename: Elena A
authors.initials: EA
authors.lastname: Karginova
authors.forename: Clyde
authors.initials: C
authors.lastname: Thornsberry
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Sahm
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001208:Asia / Q000453:epidemiology; D027081:DNA Gyrase / Q000235:genetics; D027101:DNA Topoisomerase IV / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D005060:Europe / Q000453:epidemiology; D005838:Genotype; D006801:Humans; D064704:Levofloxacin; D008800:Mexico / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D009154:Mutation; D015242:Ofloxacin / Q000494:pharmacology*; D010641:Phenotype; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013019:South Africa / Q000453:epidemiology; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects* / Q000235:genetics
chemical_list: D000890:Anti-Infective Agents; D064704:Levofloxacin; D015242:Ofloxacin; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase