title: Quinolone resistance in Escherichia coli from Accra, Ghana.
abstract: BACKGROUND
  Antimicrobial resistance is under-documented and commensal Escherichia coli can be used as indicator organisms to study the resistance in the community. We sought to determine the prevalence of resistance to broad-spectrum antimicrobials with particular focus on the quinolones, which have recently been introduced in parts of Africa, including Ghana.
  
  
  RESULTS
  Forty (13.7%) of 293 E. coli isolates evaluated were nalidixic acid-resistant. Thirteen (52%) of 2006 and 2007 isolates and 10 (66.7%) of 2008 isolates were also resistant to ciprofloxacin. All but one of the quinolone-resistant isolates were resistant to three or more other antimicrobial classes. Sequencing the quinolone-resistance determining regions of gyrA and parC, which encode quinolone targets, revealed that 28 quinolone-resistant E. coli harboured a substitution at position 83 of the gyrA gene product and 20 of these isolates had other gyrA and/or parC substitutions. Horizontally-acquired quinolone-resistance genes qnrB1, qnrB2, qnrS1 or qepA were detected in 12 of the isolates. In spite of considerable overall diversity among E. coli from Ghana, as evaluated by multilocus sequence typing, 15 quinolone-resistant E. coli belonged to sequence type complex 10. Five of these isolates carried qnrS1 alleles.
  
  
  CONCLUSIONS
  Quinolone-resistant E. coli are commonly present in the faecal flora of Accra residents. The isolates have evolved resistance through multiple mechanisms and belong to very few lineages, suggesting clonal expansion. Containment strategies to limit the spread of quinolone-resistant E. coli need to be deployed to conserve quinolone effectiveness and promote alternatives to their use.
authors.affiliation: Department of Biology, Haverford College, Haverford, PA 19041, USA.
authors.forename: Sreela S
authors.initials: SS
authors.lastname: Namboodiri
authors.forename: Japheth A
authors.initials: JA
authors.lastname: Opintan
authors.forename: Rebeccah S
authors.initials: RS
authors.lastname: Lijek
authors.forename: Mercy J
authors.initials: MJ
authors.lastname: Newman
authors.forename: Iruka N
authors.initials: IN
authors.lastname: Okeke
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D027081:DNA Gyrase / Q000235:genetics; D004252:DNA Mutational Analysis; D027101:DNA Topoisomerase IV / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005869:Ghana; D006801:Humans; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D009268:Nalidixic Acid / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D009268:Nalidixic Acid; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase