title: Mechanisms of and risk factors for fluoroquinolone resistance in clinical Enterococcus faecalis isolates from patients with urinary tract infections.
abstract: We examined Enterococcus faecalis strains clinically isolated from 100 patients with urinary tract infections (UTIs) for their susceptibility to levofloxacin (LVX) by measuring the MIC and investigated amino acid mutations by direct DNA sequencing, which were then correlated with LVX resistance. Next, we studied risk factors for LVX resistance, such as age, gender, and previous fluoroquinolone use, and investigated the statistical correlation of these risk factors with each amino acid mutation and LVX resistance. Of the 100 isolates tested, 14 isolates showed LVX resistance and all of these isolates had amino acid mutations. We demonstrated that 2 out of 4 mutations (Ser83-to-Ile in gyrA and Ser80-to-Ile in parC) had a significant correlation with LVX resistance. There was a significant relationship between isolates with 2 or 3 amino acid mutations and LVX resistance. In addition, we found a significant correlation between the previous use of fluoroquinolones and LVX resistance or the presence of mutations and also demonstrated that previous use of other types of antibiotics was significantly related to the presence of mutations by multivariate analysis. In conclusion, we found significant correlation between amino acid mutations in E. faecalis, LVX resistance, and risk factors such as previous use of fluoroquinolones.
authors.affiliation: Department of Surgery, Division of Urology, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Tomihiko
authors.initials: T
authors.lastname: Yasufuku
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shigemura
authors.forename: Toshiro
authors.initials: T
authors.lastname: Shirakawa
authors.forename: Minori
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Nakano
authors.forename: Kazushi
authors.initials: K
authors.lastname: Tanaka
authors.forename: Soichi
authors.initials: S
authors.lastname: Arakawa
authors.forename: Masato
authors.initials: M
authors.lastname: Kawabata
authors.forename: Masato
authors.initials: M
authors.lastname: Fujisawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D027101:DNA Topoisomerase IV / Q000235:genetics; D024881:Drug Resistance, Bacterial; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000302:isolation & purification; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy / Q000382:microbiology*; D006801:Humans; D064704:Levofloxacin; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D020125:Mutation, Missense; D015242:Ofloxacin / Q000008:administration & dosage / Q000494:pharmacology*; D012307:Risk Factors; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000382:microbiology*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D064704:Levofloxacin; D015242:Ofloxacin; D027101:DNA Topoisomerase IV