title: Quinolone resistance of Salmonella enterica serovar Virchow isolates from humans and poultry in Israel: evidence for clonal expansion.
abstract: Salmonella enterica serovar Virchow is highly prevalent in humans and farm animals in Israel. In addition to high rates of resistance to multiple antibiotics, this serovar exhibits a high incidence of resistance to nalidixic acid. More than 90% of Salmonella serovar Virchow isolates of human and poultry origin obtained from 1997 to 2004 were resistant to nalidixic acid (MIC > or = 128 microg/ml), with reduced susceptibility to ciprofloxacin (MIC between 0.125 and 0.250 microg/ml). Most isolates belonged to two predominant, closely related pulsed-field gel electrophoresis image types. Investigation of the mechanisms of quinolone resistance revealed that this pathogen probably emerged from a parental clone that overproduced the AcrAB efflux pump and had a single point mutation in gyrA leading to the Asp87Tyr substitution. The close resemblance between human and poultry isolates points to poultry as a likely source of Salmonella serovar Virchow in the food chain.
authors.affiliation: Department of Biotechnology and Food Engineering, Technion, Haifa, Israel.
authors.forename: Hadas
authors.initials: H
authors.lastname: Solnik-Isaac
authors.forename: Miriam
authors.initials: M
authors.lastname: Weinberger
authors.forename: Mina
authors.initials: M
authors.lastname: Tabak
authors.forename: Alon
authors.initials: A
authors.lastname: Ben-David
authors.forename: Dina
authors.initials: D
authors.lastname: Shachar
authors.forename: Sima
authors.initials: S
authors.lastname: Yaron
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D027081:DNA Gyrase / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006801:Humans; D007557:Israel / Q000453:epidemiology; D017720:Molecular Epidemiology; D017354:Point Mutation; D011200:Poultry; D015363:Quinolones / Q000494:pharmacology*; D012480:Salmonella Infections / Q000453:epidemiology / Q000382:microbiology*; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000382:microbiology*; D019779:Salmonella enterica / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: C493251:AcrAB-TolC protein, Salmonella enterica; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D015363:Quinolones; D027081:DNA Gyrase