β-lactamase . Klebsiella pneumoniae . PCR-mapping . DNA sequencing Introduction
Abstract :
[en] 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 byblaCTX-M-14b gene located on a 50-kb highly conjugative plasmid. The study of the genetic context of blaCTX-M-14b was realized by PCR mapping and DNA sequencing. A novel variant of tnpISEcp1 designated ISEcp1C was detected
upstream of the gene.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Ben Achour, Nahed
Power, Pablo
Mercuri, Paola ; Université de Liège > Département des sciences de la vie > Macromolécules biologiques
Ben Moussa, Mohamed
Galleni, Moreno ; Université de Liège > Département des sciences de la vie > Macromolécules biologiques
Belhadj, Omrane
Language :
English
Title :
First detection of a transferable blaCTX-M-14b gene in a Klebsiella pneumoniae clinical isolate from Tunisia and analysis of its genetic context
Publication date :
2012
Journal title :
Annals of Microbiology
ISSN :
1590-4261
eISSN :
1869-2044
Publisher :
Springer-Verlag and the University of Milan 2012, Germany