Affiliation:
1. 1 UMR 5234 CNRS, University Bordeaux 2, 146 rue Leo Saignat, 33076 Bordeaux, France
2. 2 Laboratory of Biology, Aziza Othmana Hospital, Tunis, Tunisia
Abstract
Abstract
Objectives
A burn unit of a hospital in Tunis underwent an endemic situation caused by imipenem-resistant Pseudomonas aeruginosa. For nine non-repetitive isolates of a clonal VIM-2-producing strain, the blaVIM-2 genetic background was characterized and the associated qnrVC1 gene molecularly analysed.
Methods
The imipenem resistance mechanism was investigated by phenotypic and molecular tests, and resistance transfer was studied by conjugation and transformation experiments. The integron's structure was characterized by sequencing, and qnrVC1 expression was explored after cloning experiments.
Results
The nine VIM-2-producing strains were collected from eight patients and one environmental sample. All transfer assays failed, suggesting a chromosomal location of blaVIM-2. This latter was found to be part of a class 1 integron of ∼7500 bp, which also contains blaOXA-2, aadA1 and two copies of the aadB, arr-6 and qnrVC1 genes. qnrVC1 exhibited higher homology with the chromosomally encoded qnr genes of Vibrionaceae than with plasmid-mediated qnr genes of Enterobacteriaceae. The qnrVC1 gene cassette possesses a promoter allowing its expression, and it conferred decreased fluoroquinolone susceptibility to Escherichia coli. Additionally, on the same integron, genes encoding an uncommon group IIC-attC intron were detected.
Conclusions
A VIM-2-producing P. aeruginosa outbreak led us to characterize an integron harbouring a qnrVC1 cassette and a new group IIC-attC intron. This is the first known description of a qnr determinant in a P. aeruginosa strain. Its presence conferred a low level of resistance to quinolones in E. coli, which might favour the emergence of highly resistant mutants.
Publisher
Oxford University Press (OUP)
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology,Microbiology (medical)
Reference20 articles.
1. Emerging infections in burns;Branski;Surg Infect (Larchmt),2009
2. Acquired carbapenemases in Gram-negative bacterial pathogens: detection and surveillance issues;Miriagou;Clin Microb Infect,2010
3. Comparative study of antibiotic resistance in bacteria isolated from burned patients during two periods (2005–2008, 2008–2011) and in two hospitals (Hospital Aziza Othmana, Trauma and Burn Center);Thabet;Tunis Med,2013
4. Molecular characterization of a novel class 1 integron containing blaGES-1 and a fused product of aac3-Ib/aac6′-Ib' gene cassettes in Pseudomonas aeruginosa;Dubois;Antimicrob Agents Chemother,2002
5. Spread of OXA-48-positive carbapenem-resistant Klebsiella pneumoniae isolates in Istanbul, Turkey;Carrer;Antimicrob Agents Chemother,2008
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