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Background: Bacterial resistance to commonly-used antibiotics has been on the increase especially in the clinical settings. This study focused on the detection of plasmid-mediated quinolone resistance (PMQR) determinants in ciprofloxacin-resistant bacteria recovered from Urinary Tract Infection (UTI) samples. Results: Already characterized isolates from urine samples of UTI-diagnosed in- and out- patients were obtained from the culture pool of the Department of Medical Microbiology and Parasitology, University College Hospital (UCH), Ibadan, Nigeria. A total of seventy-three ciprofloxacin-resistant isolates were used in this study. Of the 73 UTI isolates, 43 carried at least one of the four PMQR genes targeted and they belonged to eight bacterial genera namely: Escherichia (25), Klebsiella (10), Pseudomonas (2), Proteus (2) and one isolate each belonging to Enterobacter, Acinetobacter, Citrobacter and Salmonella genera. qnrA was detected in 10.9% (8/73) of the isolates while the occurrence of qnrB and qnrS was 32.9% (24/73) and 20.5% (15/73), respectively. The quinolone efflux pump (qepA) was detected in 9/73 (12.3%) of the isolates. Thirty of the isolates carried only one PMQR gene, while thirteen carried two PMQR genes. There was no carriage of more than two PMQR genes in the forty-three isolates from which PMQR genes were detected. Conclusion: This study reports the carriage of PMQR determinants by eight of the nine Gram-negative bacterial genera from urinary sources in patients attending the University College Hospital, Ibadan over the four-month period of study. This is quite worrisome as it suggests a high contribution of UTI cases to the burden of quinolone resistance. There is a need for more studies of this nature in other hospitals in Nigeria, to develop a database on the contribution of UTI cases to quinolone resistance. [ABSTRACT FROM AUTHOR]

Antimicrobial usage in aquaculture selects for antimicrobial-resistant microorganisms in the marine environment. The relevance of this selection to terrestrial animal and human health is unclear. Quinolone-resistance genes qnrA, qnrB, and qnrS were chromosomally located in four randomly chosen quinolone-resistant marine bacteria isolated from an aquacultural area with heavy quinolone usage. In quinolone-resistant uropathogenic clinical isolates of Escherichia coli from a coastal area bordering the same aquacultural region, qnrA was chromosomally located in two E. coli isolates, while qnrB and qnrS were located in small molecular weight plasmids in two other E. coli isolates. Three quinolone-resistant marine bacteria and three quinolone-resistant E. coli contained class 1 integrons but without physical association with PMQR genes. In both marine bacteria and uropathogenic E. coli, class 1 integrons had similar co-linear structures, identical gene cassettes, and similarities in their flanking regions. In a Marinobacter sp. marine isolate and in one E. coli clinical isolate, sequences immediately upstream of the qnrS gene were homologous to comparable sequences of numerous plasmid-located qnrS genes while downstream sequences were different. The observed commonality of quinolone resistance genes and integrons suggests that aquacultural use of antimicrobials might facilitate horizontal gene transfer between bacteria in diverse ecological locations. [ABSTRACT FROM AUTHOR]