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AAC-(6)-Ib-cr, QnrC and QnrS determinants among bacterial isolates from wild and food-producing animals in Portugal

Abstract number: P757

Objectives: Plasmid-mediated quinolone resistance (PMQR) is increasingly identified worldwide in Enterobacteriaceae of human origin. However, few reports describe their occurrence among bacteria from animal origin. The aim of this study was to evaluate the extension of PMQR in animals.

Methods: We screened two collections of Enterobacteriaceae isolates (n = 140) for the presence of PMQR determinants, identified at National Laboratory of Veterinary Research (LNIV, Lisbon), during a period of two years (2008–2009). A total of 51 Salmonella isolates from different serotypes were isolated from layers, and 89 Escherichia coli were isolated from farm animals, birds and mammals. PCR and nucleotide sequencing were used with specific primers to screen for the presence of the following genes: qnrA, qnrB, qnrC, qnrD, qnrS, aac-(6')-Ib-cr and qepA genes. Susceptibility testing of isolates carrying PMQR determinants was performed against quinolones (nalidixic acid, ciprofloxacin, norfloxacin, pefloxacin, orbifloxacin, marbofloxacin and enrofloxacin) by disk diffusion and MIC methods, and interpreted according to SFM veterinary and EFSA guidelines, respectively.

Results: We identified a qnrC-positive Salmonella enteritidis isolated in a layer chicken. Three qnr genes were identified as qnrS1 and were detected in E. coli isolates from a broiler, a dog and a turtle-dove. The aac-(6')-Ib-cr gene was detected in an E. coli isolated from a dolphin. None of the isolates, from both collections, carried qnrA, qnrB, qnrD or qepA genes. The isolates with aac-(6')-Ib-cr and the other two QnrS1 determinants showed diminished susceptibility to all fluoroquinolones tested and to nalidixic acid but one of the isolates with QnrS1 determinant was susceptible to all antibiotics. Isolates with QnrC determinant showed susceptibility to pefloxacin and marbofloxacin.

Conclusions: This survey showed that PMQR determinants are present in animals from different environments in Portugal, including food-producing animals. To our knowledge this is the first report of a qnrC gene in isolates from animal origin. The study highlights the need of surveillance of this resistance mechanism and reinforces a more careful use of fluoroquinolones.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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