title: Escherichia coli clonal group A among uropathogenic infections in Mexico City.
abstract: Escherichia coli clonal group A (CGA) causes urinary tract and other extra-intestinal infections in humans. CGA is an important cause of trimethoprim/sulfamethoxazole (SXT) resistance in extra-intestinal pathogens. We examined the extent to which resistance in this area is related to CGA dissemination of E. coli from urinary tract infections (UTIs) in Mexico City. The virulence backgrounds of the isolates were also characterized. In this study, the frequency of resistance to SXT used for UTI treatment was high (56-65 %), and CGA isolates accounted for 9 of the 78 SXT-resistant isolates (11.5 %). Although all CGA isolates were found to be multidrug resistant (MDR), none of them were extended-spectrum β-lactamase-producing organisms. The prevalence of CGA among the 45 MDR isolates that we identified was 20 %, indicating that this clonal group moderately contributes to the antibiotic resistance of uropathogenic E. coli isolates in this region. Most of the nine CGA isolates carried transferable, large-size plasmids of approximately 80 to 100 kb, which were able to transfer antimicrobial resistance to E. coli J53 in mating assays. CGA isolates mainly belonged to phylogenetic groups F and D. We found no association between antimicrobial resistance and virulence-associated genes: the median virulence scores of CGA isolates were slightly higher (4.6) than those of non-CGA isolates, whether they were susceptible (3.7) or resistant (3.5) to SXT. Our results indicate that CGA is not a major contributor to the high level of resistance to SXT in this region but, instead, seems to be an important constituent of MDR isolates from UTIs.
authors.affiliation: Dirección de Investigación, Hospital General Dr. Gea González, Tlalpan, Ciudad de México 14080, Mexico.|Departamento de Salud Pública, Facultad de Medicina, UNAM, Ciudad de México 04510, Mexico.
authors.forename: Angel
authors.initials: A
authors.lastname: Manjarrez-Hernandez
authors.affiliation: Departamento de Salud Pública, Facultad de Medicina, UNAM, Ciudad de México 04510, Mexico.|Laboratorio de Patogenicidad Bacteriana, Edificio de Investigación Hemato-Oncología 5to, Piso Hospital Infantil de México 'Federico Gómez', C.P. 06720 Ciudad de México, Mexico.
authors.forename: José
authors.initials: J
authors.lastname: Molina-López
authors.affiliation: Departamento de Salud Pública, Facultad de Medicina, UNAM, Ciudad de México 04510, Mexico.|Dirección de Investigación, Hospital General Dr. Gea González, Tlalpan, Ciudad de México 14080, Mexico.
authors.forename: Sandra
authors.initials: S
authors.lastname: Gavilanes-Parra
authors.affiliation: Dirección de Investigación, Hospital General Dr. Gea González, Tlalpan, Ciudad de México 14080, Mexico.
authors.forename: Rigoberto
authors.initials: R
authors.lastname: Hernandez-Castro
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D005838:Genotype; D006801:Humans; D008800:Mexico / Q000453:epidemiology; D010802:Phylogeny; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology; D014552:Urinary Tract Infections / Q000453:epidemiology / Q000382:microbiology*; D056689:Uropathogenic Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D037521:Virulence Factors / Q000235:genetics; D001618:beta-Lactamases / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D037521:Virulence Factors; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D001618:beta-Lactamases