First characterization of a Providencia stuartii clinical isolate from a Tunisian intensive care unit coproducing VEB-1-a, OXA-2, qnrA6 and aac(6′)-Ib-cr determinants
✍ Scribed by Mahrouki, Sihem; Chihi, Hela; Bourouis, Amel; Ben Moussa, Mohamed; Belhadj, Omrane
- Book ID
- 121469574
- Publisher
- SciELO
- Year
- 2014
- Tongue
- English
- Weight
- 339 KB
- Volume
- 18
- Category
- Article
- ISSN
- 1413-8670
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✦ Synopsis
A clinical Providencia stuartii isolate SM662 was recovered from a patient hospitalized in the intensive care unit at the Military hospital, Tunisia. This isolate was resistant to penicillins, cephalosporins, aminoglycosides and fluoroquinolones. A marked in vitro synergy between ceftazidime or cefotaxime and amoxicillin–clavulanic acid on Mueller-Hinton agar plates suggested the presence of an extended-spectrum-β-lactamase. In addition, an unusual synergy was found between cefepime or aztreonam, and cefoxitin or imipenem on a double disk synergy test suggesting a VEB-type extended-spectrum-β-lactamase. The characterization of β-lactamases and associated resistance genes was performed by isoelectric focusing, polymerase chain reaction and nucleotide sequencing. Two β-lactamases bands with __p__I values of 5.4 and 7.7, which were matched to TEM-1, VEB-1-a and OXA-2-like β-lactamases were detected. The bla~VEB-1-a~ gene was found to be associated with complex genetic structures, including Re elements. These β-lactamases were not transferred by electroporation or conjugation experiments to the transconjugants and electroporants. Hybridization methods showed that the extended-spectrum-β-lactamase encoding gene may have a chromosomal localization. The isolate SM662 produced the quinolone resistance determinants __qnrA__6 and aac(6′)-Ib-cr which were successfully transferred. The detection of an associated chromosomal quinolone resistance revealed the presence of a gyrA mutation at codon 83 (Ser83Ile). This is the first report of the linkage VEB-1-a/OXA-2-like in P. stuartii associated with the description of qnrA6 and aac(6′)-Ib-cr genes in this isolate.
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