Mutations in the quinolone resistance determining region in Staphylococcus epidermidis recovered from conjunctiva and their association with susceptibility to various fluoroquinolones

Division for Vision Research, National Institute of Sensory Organs, National Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo 152-8902, Japan.
The British journal of ophthalmology (Impact Factor: 2.81). 07/2008; 92(6):848-51. DOI: 10.1136/bjo.2007.129858
Source: PubMed

ABSTRACT Staphylococcus epidermidis is one of the prominent pathogens in ocular infection. The prevalence of mutations in the quinolone resistance determining region (QRDR) area in S epidermidis isolated from the ocular surface and its association with fluoroquinolone resistance has not been fully elucidated.
Mutations in the QRDR of gyrA, gyrB, parC, and parE genes of 138 isolates of S epidermidis recovered from the human conjunctival flora were analysed. The minimal inhibitory concentrations (MICs) of four fluoroquinolones (levofloxacin, gatifloxacin, moxifloxacin and tosufloxacin) against these isolates were also determined using agar dilution methods.
The MIC(90) values of levofloxacin, gatifloxacin, moxifloxacin and tosufloxacin were 3.13, 1.56, 0.78 and 3.13 microg/ml, respectively. The MIC values of all fluoroquinolones showed a bimodal distribution (susceptible strain and less susceptible strain). Mutations with amino acid substitution in the QRDR were present in 70 (50.7%) isolates. 19 different combinations of mutations were detected: 3 isolates (2.2%) had four mutations, 8 (5.8%) had three mutations, 43 (31.2%) had double mutations and 16 (11.6%) had single mutations. Isolates with mutations in the QRDR of both gyrA and parC (n = 53) were less susceptible to fluoroquinolones.
The present findings show that approximately half the S epidermidis isolates from the normal human conjunctiva have mutation(s) in the QRDR. The presence of mutations in both gyrA and parC is strongly associated with reduced susceptibility to fluoroquinolones.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In vitro activity of ozenoxacin, a novel nonfluorinated topical (L. D. Saravolatz and J. Leggett, Clin. Infect. Dis. 37:1210–1215, 2003) quinolone, was compared with the activities of other quinolones against well-characterized quinolone-susceptible and quinolone-resistant Gram-positive bacteria. Ozenoxacin was 3-fold to 321-fold more active than other quinolones. Ozenoxacin could represent a first-in-class nonfluorinated quinolone for the topical treatment of a broad range of dermatological infections.
    Antimicrobial Agents and Chemotherapy 12/2013; 57(12). DOI:10.1128/AAC.01509-13 · 4.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The fourth-generation 8-methoxyfluoroquinolone moxifloxacin is available as an 0.5% ophthalmic solution for use in the treatment of bacterial conjunctivitis. Moxifloxacin had good activity against various Gram-positive and -negative ocular isolates in vitro, and moxifloxacin 0.5% ophthalmic solution achieved good penetration into ocular tissues in healthy volunteers and patients undergoing ocular surgery. The efficacy of moxifloxacin 0.5% ophthalmic solution in the treatment of bacterial conjunctivitis has been shown in three randomized, double-blind, multicentre trials. In a trial in patients aged ≥1 year, the clinical success rate was significantly higher with moxifloxacin 0.5% ophthalmic solution than with placebo. In a trial in patients aged ≥12 years, moxifloxacin 0.5% ophthalmic solution was noninferior to levofloxacin 0.5% ophthalmic solution in terms of the clinical success rate. In a third trial, the clinical cure rate was significantly higher with moxifloxacin 0.5% ophthalmic solution than with trimethoprim 1.0%/ polymixin B 10 000 IU/mL ophthalmic solution in paediatric patients aged ≤18 years. Moxifloxacin 0.5% ophthalmic solution was well tolerated in patients with bacterial conjunctivitis. Ocular adverse events (e.g. eye pain, eye irritation) were the most commonly reported treatment-related adverse events, with the majority being of mild severity.
    Drugs 01/2011; 69(9). DOI:10.2165/00003495-200969090-00009 · 4.13 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: Conjunctivitis isa common ocular infection in our environment. The indiscriminate use of broad spectrum antibiotics to treat conjunctivitis has generated resistant organisms. Objective: Identify the most common organisms isolated from samples of conjunctival origin and know their antibiotic susceptibility. Material and methods: Retrospective review of isolates from conjunctival scrapingsobtained during 2011. Results: We collected 68 isolated of conjunctival origin. They were from 33 men (49%) and 35 women (51%). The average age was 47.23 years. The culture was positive in 75%, and we identified 11 microorganisms. The coagulase-negative Staphylococcus,led by Staphylococcus epidermidis were the most frequent microorganisms. The coagulase-negative Staphylococcus was sensitive to vancomycin, ciprofloxacin and gentamicin, and was resistant to cefazolin, sulfamethoxazole and oxacillin. 97% of isolates of Coagulase- negative Staphylococcus were multiresistant to antibiotics, being resistant to five or more antibiotics in most cases. Conclusions: Staphylococcus coagulase negative were the most frequent microorganisms isolated from conjunctival infections, most of the species isolated were susceptible to ciprofloxacin, gentamicin and vancomycin; most of the isolates showed multidrug resistance to antibiotics.
    Revista Mexicana de Oftalmologia 01/2012; 86(4):223-230. DOI:10.1016/j.mexoft.2014.01.001

Preview (2 Sources)

Available from