Molecular epidemiology of extended-spectrum β-lactamase-producing Klebsiella pneumoniae strains in a university hospital in Tunis, Tunisia, 1999–2005

• Published in: Clinical microbiology and infection Vol. 16; no. 2; pp. 157 - 164
• Main Authors: Elhani, D., Bakir, L., Aouni, M., Passet, V., Arlet, G., Brisse, S., Weill, F.-X.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier Ltd 01-02-2010; Blackwell Publishing Ltd; Wiley-Blackwell; Elsevier for the European Society of Clinical Microbiology and Infectious Diseases
• Subjects: Bacterial Typing Techniques; beta-Lactamases; beta-Lactamases - biosynthesis; Biological and medical sciences; Cluster Analysis; CTX-M-14; CTX-M-15; CTX-M-27; Gene Transfer, Horizontal; Genotype; Hospitals, University; Humans; IncFII; IncHI2; IncL/M; Infectious diseases; Klebsiella Infections; Klebsiella Infections - microbiology; Klebsiella pneumoniae; Klebsiella pneumoniae - classification; Klebsiella pneumoniae - enzymology; Klebsiella pneumoniae - isolation & purification; Life Sciences; Medical sciences; Microbiology and Parasitology; MLST; Molecular Epidemiology; Plasmids; Polymerase Chain Reaction; Polymorphism, Genetic; replicon typing; Santé publique et épidémiologie; Sequence Analysis, DNA; SHV-12; SHV-2a; Tunisia; Tunisia - epidemiology; Tunisia; Africa; IncL/M; MLST; IncFII; CTX-M-15; CTX-M-27; CTX-M-14; SHV-2a; replicon typing; SHV-12; IncHI2; Klebsiella pneumoniae; Typing; IncF11; IncH12; Infection; Microbiological investigation; Molecular epidemiology; Bacteria; Hospital; Enterobacteriaceae
• ISSN: 1198-743X; 1469-0691
• DOI: 10.1111/j.1469-0691.2009.03057.x

During a period of 6 years and 5 months (January 1999 to May 2005), 103 extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolates, each from an individual patient or site, were collected at Mongi Slim University Hospital Centre, Tunis, Tunisia. The objectives of our work were the characterization of the bla genes encoding ESBLs, the investigation of clonal diversity of strains, and identification of the transmission modes of the resistance genes. We carried out detection by PCR and sequencing of the blaSHV, blaCTX-M and blaTEM genes, transferability studies, plasmid replicon typing, and analysis by multilocus sequence typing (MLST) on selected isolates. Forty-seven isolates were found to be producers of CTX-M-type ESBLs, of which 43 were CTX-M-15, two CTX-M-14 and two CTX-M-27. Fifty-eight isolates were producers of SHV-12, and three were producers of SHV-2a. More than one ESBL was detected in seven isolates, as five produced both CTX-M-15 and SHV-12, and two produced both CTX-M-27 and SHV-12. By a PCR-based replicon typing method, the plasmids carrying the blaSHV-2a or blaCTX-M-15 genes were assigned to IncFII or, more rarely, to IncL/M types. Of 12 plasmids carrying the blaSHV-12 gene, only one could be typed: it was positive for the H12 replicon. The MLST results showed large genetic background diversity in the SHV-12-producing isolates and dissemination of specific clones of the CTX-M-15-producing isolates within the same ward and among wards, and suggested endemicity with horizontal dissemination of the blaCTX-M-15 and the blaSHV-12 genes.