title: Characterisation of quinolone-resistant Escherichia coli of 1997 and 2005 isolates from poultry in Mexico.
abstract: Forty-two enrofloxacin-resistant Escherichia coli strains isolated from eggs and first-week mortality associated with yolk sac infection of two vertically integrated poultry companies of Central Mexico in 1997 and 2005 were characterised. E. coli resistance to 19 antibiotics was determined, as well as the minimum inhibitory concentrations (broth dilution) for ciprofloxacin. The presence of gyrA,B, parC,E chromosomal point mutations, qnrA,B,S plasmid genes and the aminoglycoside acetyltransferase aac(6')-Ib-cr were determined by PCR and sequencing. Resistance to ampicillin (95%), piperacillin (95%), gatifloxacin (95%), levofloxacin (95%), ampicillin/sulbactam (90%), cefazolin (85%), trimethoprim/sulfamethoxazole (80%), amoxicillin/clavulanic acid (80%), aztreonam (80%), cefepime (80%), cefotaxime (80%), ceftazidime (80%), ceftriaxone (80%) and cefoxitin (75%) was high in the 2005 strains and 19 (95%) strains were resistant to 7 or more antimicrobials. The strains from 1997 expressed high rates of resistance only to the fluoroquinolones and 4 strains (18%) expressed resistance to 7 or more antimicrobials. All strains had a gyrA mutation (Ser83Leu) and a parC mutation (Ser80Ile or Ser80Arg) and 41 (97.6%) strains had a second gyrA mutation (Asp87Asn, Asp87Tyr or Asp87Gly). Only two (4.7%) strains had a parE mutation (Ser458Ala). A total of 10 strains were positive for the aac(6')-Ib wild-type gene, 6 strains for the aac(6')-Ib-cr variant and 6 strains possessed both the wild type and the variant. No gyrB mutations or qnrA,B,S genes were detected. This is the first report in Latin America of chromosomal and plasmid quinolone resistance genes in E. coli strains recovered from poultry.
authors.affiliation: a División de Estudios de Posgrado, Posgrado en Ciencias de la Salud y Producción Animal, Facultad de Medicina Veterinaria y Zootecnia , Universidad Nacional Autónoma de México , Coyoacan , México.
authors.forename: C
authors.initials: C
authors.lastname: Del Rio-Avila
authors.affiliation: b Departamento de Medicina y Zootecnia de Aves, Facultad de Medicina Veterinaria y Zootecnia , Universidad Nacional Autónoma de México , Coyoacan , México.
authors.forename: C
authors.initials: C
authors.lastname: Rosario
authors.affiliation: c Departamento de Biología Molecular e Histocompatibilidad , Hospital General "Dr. Manuel Gea González" , Tlalpan , México.
authors.forename: S
authors.initials: S
authors.lastname: Arroyo-Escalante
authors.affiliation: c Departamento de Biología Molecular e Histocompatibilidad , Hospital General "Dr. Manuel Gea González" , Tlalpan , México.
authors.forename: E M
authors.initials: EM
authors.lastname: Carrillo-Casas
authors.affiliation: d Departamento de Enfermedades en Pequeños Rumiantes , Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias , Cuajimalpa , México.
authors.forename: E
authors.initials: E
authors.lastname: Díaz-Aparicio
authors.affiliation: e Departamento de Microbiología e Inmunología , Universidad Nacional Autónoma de México , Coyoacan , México.
authors.forename: F
authors.initials: F
authors.lastname: Suarez-Güemes
authors.affiliation: f Departamento de Diagnóstico Epidemiológico , Instituto Nacional de Salud Pública , Cuernavaca , México.
authors.forename: J
authors.initials: J
authors.lastname: Silva-Sanchez
authors.affiliation: g Laboratorio de Bacteriología Intestinal , Hospital Infantil de México , Cuauhtémoc , México.
authors.forename: J
authors.initials: J
authors.lastname: Xicohtencatl-Cortes
authors.affiliation: h Departamento de Ecología de Agentes Patógenos , Hospital General "Dr. Manuel Gea González" , Tlalpan , México.
authors.forename: P
authors.initials: P
authors.lastname: Maravilla
authors.affiliation: h Departamento de Ecología de Agentes Patógenos , Hospital General "Dr. Manuel Gea González" , Tlalpan , México.
authors.forename: R
authors.initials: R
authors.lastname: Hernández-Castro
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D024841:Fluoroquinolones / Q000494:pharmacology*; D008800:Mexico; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D010063:Ovum / Q000382:microbiology; D011200:Poultry; D011201:Poultry Diseases / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones