Genetic characterisation of extended-spectrum β-lactamases in Escherichia coli isolated from retail chicken products including CTX-M-9 containing isolates: a food safety risk factor

last updated: 2015-05-11
TitleGenetic characterisation of extended-spectrum β-lactamases in Escherichia coli isolated from retail chicken products including CTX-M-9 containing isolates: a food safety risk factor
Publication TypePapers in Scientific Journals
Year of Publication2012
AuthorsSilva N., Costa L., Gonçalves A., Sousa M., Radhouani H., Brito F., Igrejas G., and Poeta P.
Abstract

1. Bacterial resistance to β-lactam antibiotics has risen dramatically in Escherichia coli from food animals. In a previous study, 29 randomly selected chicken products, collected in Portugal, were analysed for the presence of extended-spectrum β-lactamases (ESBLs)-producing E. coli; and during this study the genetic characterisation of ESBLs genes was investigated. 2. The presence of genes encoding TEM, OXA, SHV, and CTX-M type beta-lactamases was studied by PCR followed by sequencing. Additionally, other mechanisms of antimicrobial resistance, phylogenetic groups and the presence of virulence determinants were evaluated among the isolates. 3. β-lactamases genes were identified as follows: bla (CTX-M-14) (n = 4), bla (CTX-M-1) (n = 2), bla (CTX-M-9) (n = 4) and bla (TEM-52) (n = 13). Mutations at positions -42, -18, -1, and +58 of ampC promoter region were identified in 4 non-ESBL-producing isolates. The tet(A) or tet(B) genes were identified in all tetracycline-resistant isolates; the aadA gene detected in 8 of 10 streptomycin-resistant isolates; the aac(3)-II gene in all gentamicin-resistant isolates; the cmlA gene in the chloramphenicol-resistant isolate; and sul1 and/or sul2 and/or sul3 genes were found in all trimethoprim-sulfamethoxazole-resistant isolates. The intI1 gene was detected in 8 trimethoprim-sulfamethoxazole-resistant isolates and the intI2 gene in 4 isolates; one gene cassette arrangements were identified among class 1 integrons (dfrA1 + aadA1) and among the class 2 integrons (dfrA1 + sat2 + aadA1). Among cefotaxime-resistant isolates, 16 belonged to A or B1 phylogenetic groups, while 11 isolates were classified into the D or B2 phylogroups. At least one virulence-associated gene (aer, fimA, or papC) was detected in 74·1% of the cefotaxime-resistant isolates. 4. Because ESBLs-producing bacteria are resistant to a broad range of β-lactams, infections caused by these organisms complicate therapy and limit treatment options.

JournalBritish Poultry Science
Volume53
Issue6
Pagination747-755
Date Published2012-11-07
PublisherBritish Poultry Science
DOI10.1080/00071668.2012.740554.
URLhttp://www.tandfonline.com/doi/abs/10.1080/00071668.2012.740554?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed&
KeywordsE. coli, ESBL
RightsopenAccess
Peer reviewedyes
Statuspublished

Back to top