Prevalence of quinolone resistance and mutations in the topoisomerase genes in Salmonella enterica serotype Enteritidis isolates from Serbia

• Published in: International journal of antimicrobial agents 2012-11, Vol.40 (5), p.455-457
• Main Authors: Kozoderović, Gordana, Velhner, Maja, Jelesić, Zora, Golić, Nataša, Lozo, Jelena, Kehrenberg, Corinna
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; Antibiotics. Antiinfectious agents. Antiparasitic agents; Biological and medical sciences; ciprofloxacin; Culture Media - chemistry; DNA Topoisomerases - genetics; Drug Resistance, Bacterial; genes; gyrA; Humans; Infectious Disease; Medical sciences; Microbial Sensitivity Tests; minimum inhibitory concentration; multiple drug resistance; mutation; Mutation, Missense; nalidixic acid; Pharmacology. Drug treatments; Prevalence; QRDR; Quinolones; Quinolones - pharmacology; Resistance; Salmonella Enteritidis; Salmonella enteritidis - drug effects; Salmonella enteritidis - enzymology; Salmonella enteritidis - genetics; Salmonella Infections - microbiology; sequence analysis; Serbia
• ISSN: 0924-8579; 1872-7913
• DOI: 10.1016/j.ijantimicag.2012.07.012

The prevalence of quinolone resistance was studied in Salmonella enterica serotype Enteritidis isolates collected during 2005–2010 in Southern Bačka County, Serbia. A total of 878 clinical isolates were examined, among which 19 (2.2%) nalidixic acid (NAL)-resistant S. Enteritidis were detected by selection on agar plates containing 64mg/L NAL. Antimicrobial susceptibility of the isolates was tested by the agar dilution method. According to Clinical and Laboratory Standards Institute (CLSI) breakpoints, ciprofloxacin (CIP) resistance was not present in the strains. Multiple drug resistance was rare, and resistance to NAL was most often present as a single resistance property. All but one NAL-resistant S. Enteritidis showed reduced susceptibility to CIP [i.e. minimum inhibitory concentration (MIC)≥0.125mg/L]. This isolate of human origin had a CIP MIC of 0.064mg/L and DNA sequencing revealed that it contained an Asp87Gly gyrA mutation. Most of the remaining isolates had MICs for NAL and CIP of 256mg/L and 0.256mg/L, respectively. Mutations in the Asp87 codon resulted in substitutions to Asn in most of the isolates, but Asp87Gly and Ser83Phe exchanges were also detected. No mutations were present in the gyrB, parC or parE genes. Although CIP resistance was absent, reduced susceptibility characterised by mutations in gyrA was apparent among S. Enteritidis isolates from Serbia.