Molecular characterization of plasmid-encoded ACC-1a4 beta-lactamase produced by Salmonella strains isolated from water in a Tunisian hospital

Abstract : A collection of non-typhoidal Salmonella strains, designated MMB1 to MMB18, resistant to third generation cephalosporins were isolated from water in a Tunisian hospital. Isolates harbored a new bla(ACC) gene located on a small transmissible plasmid of 5 kb. The ACC-1a4 enzyme was produced in Escherichia coli, purified and characterized. Compared to the chromosomal bla(ACC-1a) gene, the bla(ACC-1a4) exhibit three mutations. We determined the kinetic parameters of our enzyme for a representative series of beta-lactam substrates. The ACC-1a4 enzyme was active on penicillins and cephalosporins, nitrocefin and cephalothin being its best tested substrates. This is a real cause for alarm since these mutations showed that the DNA sequence of bla(ACC) is an intermediate between those of bla(ACC-1a) and bla(ACC-4) and might increase the probability of the appearance and spreading of ACC-4-mediated resistance in the hospital environment.
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Annals of Microbiology, Springer, 2012, 62 (1), pp.31-36. 〈10.1007/s13213-011-0221-x〉
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Contributeur : Institut Pasteur Tunis <>
Soumis le : dimanche 2 octobre 2016 - 23:20:25
Dernière modification le : lundi 5 février 2018 - 15:22:12

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Melek Ben Aissa, Adriana Herteg Fernea, Hanene Bouraoui, Ridha Ben Aissa, Paola Sandra Mercuri, et al.. Molecular characterization of plasmid-encoded ACC-1a4 beta-lactamase produced by Salmonella strains isolated from water in a Tunisian hospital. Annals of Microbiology, Springer, 2012, 62 (1), pp.31-36. 〈10.1007/s13213-011-0221-x〉. 〈pasteur-01375141〉

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