Molecular epidemiology of extended-spectrum β-lactamase-producing Klebsiella pneumoniae strains in a university hospital in Tunis, Tunisia, 1999–2005
ABSTRACT During a period of 6 years and 5 months (January 1999 to May 2005), 103 extended-spectrum beta-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 bla(SHV), bla(CTX-M) and bla(TEM) 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 bla(SHV-2a) or bla(CTX-M-15) genes were assigned to IncFII or, more rarely, to IncL/M types. Of 12 plasmids carrying the bla(SHV-12) gene, only one could be typed: it was positive for the HI2 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 bla(CTX-M-15) and the bla(SHV-12) genes.
Full-textDOI: · Available from: François-Xavier Weill, Jul 07, 2015
- SourceAvailable from: Ben Slama KarimAnnales de biologie clinique 01/2011; 69(6):742-4. DOI:10.1684/abc.2011.0640 · 0.42 Impact Factor
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ABSTRACT: Klebsiella pneumoniae ML2508 was isolated from a patient at the surgery unit of the Military Hospital (Hôpital Militaire de Tunis), Tunisia. It was identified as a producer of extended-spectrum β-lactamases (ESBLs) by the double-disk synergy test. The β-lactamases produced by the strain were characterized by isoelectric focusing, determination of the specific activities against penicillins and cephalosporins, determination of the inhibitory concentration required to inhibit 50% of enzyme activity (IC50), and the inhibition effect of EDTA on putative metallo-β-lactamases. The crude extract of K. pneumoniae ML2508 contains five different β-lactamases with pI 5.5, 7.3, 7.6, 8.1, and 8.6. Only the β-lactamase with pI 8.1 was transferred by transformation and conjugation experiments. Molecular characterization of these genes was performed by PCR and sequencing. The four chromosomal β-lactamases are TEM (pI 5.5), 2 SHV (pI 7.3 and 7.6), and CTX-M-28 (pI 8.6). The β-lactamase with pI 8.1 was encoded by bla CTX-M-14b gene located on a 50-kb highly conjugative plasmid. The study of the genetic context of bla CTX-M-14b was realized by PCR-mapping and DNA sequencing. A novel variant of tnp ISEcp1 designated ISEcp1C was detected upstream of the gene.Annals of Microbiology 12/2012; 62(4). DOI:10.1007/s13213-012-0430-y · 1.04 Impact Factor
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ABSTRACT: To investigate the antimicrobial resistance, extended-spectrum beta-lactamases (ESBLs) and clones of Klebsiella pneumoniae isolates causing bacteraemia or urinary tract infection (UTI) in Korea, a total of 406 K. pneumoniae isolates from patients with bacteraemia (221 isolates) and UTI (185 isolates) were collected from 10 tertiary-care Korean hospitals from July 2006 to October 2007. In vitro antimicrobial susceptibility testing was performed for all isolates and ESBL production was tested. Multilocus sequence typing (MLST) analyses were performed to characterize genotypes of ESBL-producing K. pneumoniae isolates. PFGE was performed for sequence type 11 (ST11) isolates. Forty-seven UTI isolates (25.4 %) produced ESBLs, while 30 bacteraemia isolates (13.6 %) produced ESBLs (P=0.002). Among 77 ESBL-producing isolates, thirty-two (41.6 %) produced SHV-type ESBLs. bla(CTX-M) genes such as bla(CTX-M-14) and bla(CTX-M-15) were detected in 36.4 %. MLST and PFGE analyses showed that ST11 was dominant in ESBL-producing K. pneumoniae isolates causing UTI (57.4 %) and in those causing bacteraemia (70.0 %) and has been prevalent in Korean hospitals. ST11 isolates harbour a combination of different ESBL genes. The ST11 clone of ESBL-producing K. pneumoniae isolates prevails in Korea, but most isolates might acquire ESBL genes independently or several different clones might be distributed in Korea.Journal of Medical Microbiology 04/2010; 59(Pt 7):822-8. DOI:10.1099/jmm.0.018119-0 · 2.27 Impact Factor