title: Prevalence of gyrA Mutations in Nalidixic Acid-Resistant Strains of Salmonella Enteritidis Isolated from Humans, Food, Chickens, and the Farm Environment in Brazil.
abstract: Salmonella Enteritidis strains that are resistant to nalidixic acid and exhibit reduced susceptibility to fluoroquinolones have been increasing worldwide. In Brazil, few studies have been conducted to elucidate the quinolone resistance mechanisms of S. Enteritidis strains. This study analyzed the profile of gyrA, gyrB, parC, and parE mutations and plasmid-mediated quinolone resistance (PMQR) mechanisms in S. Enteritidis NalRstrains isolated in Brazil. Moreover, the minimum inhibitory concentrations (MICs) of ciprofloxacin were evaluated in 84 NalRstrains and compared with 20 NalSstrains. The mutation profiles of the gyrA gene were accessed by high-resolution melting analysis and gyrB, parC, and parE by quinolone resistance-determining region sequencing. The MICs of ciprofloxacin were accessed with Etest®. The strains were divided into five gyrA melting profiles. The NalRstrains exhibited the following amino acid substitutions: Ser97→Pro, Ser83→Phe, Asp87→Asn, or Asp87→Tyr. The average MICs of ciprofloxacin was 0.006 μg/ml in the NalSand 0.09 μg/ml in the NalRstrains. No points of mutation were observed in the genes gyrB, parC, and parE. The qnrB gene was found in two strains. In conclusion, the reduced susceptibility to ciprofloxacin observed in NalRstrains may cause treatment failures once this drug is commonly used to treat Salmonella infections. Moreover, this reduced susceptibility in these Brazilian strains was provided by target alteration of gene gyrA and not by mobile elements, such as resistance plasmids.
authors: 1 Universidade de São Paulo - Faculdade de Ciências Farmacêuticas de Ribeirão Preto , Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Ribeirão Preto, Brazil .
authors: Fábio
authors: F
authors: Campioni
authors: 1 Universidade de São Paulo - Faculdade de Ciências Farmacêuticas de Ribeirão Preto , Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Ribeirão Preto, Brazil .
authors: Roberto Antonio
authors: RA
authors: Souza
authors: 1 Universidade de São Paulo - Faculdade de Ciências Farmacêuticas de Ribeirão Preto , Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Ribeirão Preto, Brazil .
authors: Vinicius Vicente
authors: VV
authors: Martins
authors: 1 Universidade de São Paulo - Faculdade de Ciências Farmacêuticas de Ribeirão Preto , Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Ribeirão Preto, Brazil .
authors: Eliana Guedes
authors: EG
authors: Stehling
authors: 2 Instituto Adolfo Lutz de Ribeirão Preto-Rua Minas , Ribeirão Preto, Brazil .
authors: Alzira Maria Morato
authors: AMM
authors: Bergamini
authors: 1 Universidade de São Paulo - Faculdade de Ciências Farmacêuticas de Ribeirão Preto , Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Ribeirão Preto, Brazil .
authors: Juliana Pfrimer
authors: JP
authors: Falcão
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001938:Brazil / Q000453:epidemiology; D002645:Chickens; D002939:Ciprofloxacin / Q000494:pharmacology; D027081:DNA Gyrase / Q000235:genetics* / Q000378:metabolism; D027101:DNA Topoisomerase IV / Q000235:genetics / Q000378:metabolism; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D000072480:Farms; D015870:Gene Expression; D006801:Humans; D008461:Meat Products / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009268:Nalidixic Acid / Q000494:pharmacology*; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D011201:Poultry Diseases / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D015995:Prevalence; D012480:Salmonella Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D012477:Salmonella enteritidis / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D009268:Nalidixic Acid; D002939:Ciprofloxacin; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase
keywords: Salmonella Enteritidis; ciprofloxacin; gyrA mutations; nalidixic acid; quinolone resistance; resistance mechanisms