Occurrence of clinical isolates of Klebsiella pneumoniae harboring chromosomally mediated and plasmid-mediated CTX-M-15 β-lactamase in a Tunisian hospital

• Published in: Canadian journal of microbiology Vol. 58; no. 9; pp. 1099 - 1103
• Main Authors: Chouchani, Chedly, El Salabi, Allaaeddin, Marrakchi, Rim, Abouelkacem, Nader, Walsh, Timothy R
• Format: Journal Article
• Language: English
• Published: Ottawa, ON NRC Research Press 01.09.2012; National Research Council of Canada
• Subjects: Anti-Bacterial Agents - pharmacology; Antibiotic resistance; bacteria; Bacteriology; beta-Lactam Resistance - genetics; beta-lactamase; beta-Lactamases - genetics; Biological and medical sciences; bla; BLSE; cephalosporins; CTX-M-15; digestion; disease control; DNA, Bacterial - genetics; Drug resistance in microorganisms; Drug Resistance, Bacterial - genetics; ESBL; extended-spectrum β-lactamase; Fundamental and applied biological sciences. Psychology; gels; genes; Genetic aspects; Hospitals; Humans; Infection control; ISEcp1; Klebsiella; Klebsiella Infections - microbiology; Klebsiella pneumoniae; Klebsiella pneumoniae - drug effects; Klebsiella pneumoniae - enzymology; Klebsiella pneumoniae - genetics; Klebsiella pneumoniae - isolation & purification; Microbiology; Miscellaneous; morbidity; mortality; multiple drug resistance; patients; phenotype; physicians; plasmids; Plasmids - genetics; polymerase chain reaction; Properties; Tunisia; Tunisie; β-lactamases à spectre étendu; Tunisia; North Africa; Africa; Plasmid; Bacteria; Clinical isolate; Extended-spectrum β-lactamase; Klebsiella pneumoniae; Enterobacteriaceae
• ISSN: 1480-3275; 0008-4166; 1480-3275
• DOI: 10.1139/w2012-089

The spread of multidrug-resistant strains of Klebsiella pneumoniae in hospitals is of concern to clinical microbiologists, health care professionals, and physicians because of the impact infections caused by these bacteria have in causing morbidity and mortality. Clinical isolates of K. pneumoniae have been found to show resistance to third-generation cephalosporins as a result of acquiring extended-spectrum β-lactamase-producing genes, such as blaCTX₋M. Since little is known about the mechanisms of antibiotic resistance observed in Kasserine hospital, Tunisia, this study was undertaken to investigate the mechanisms by which clinical isolates of K. pneumoniae resist β-lactam antibiotics. Twelve strains of K. pneumoniae were collected from patients admitted to Kasserine hospital; these isolates showed multiresistance phenotypes. Molecular genetics investigations using polymerase chain reaction, S1 digestion, and pulsed-field gel electrophoresisshowed that blaCTX₋M₋₁₅ in association with ISEcp1 is responsible for the resistance of these strains to third-generation cephalosporins. It has been determined that blaCTX₋M₋₁₅ is chromosomally mediated and plasmid mediated, which alarming need for infection control to prevent the outbreak of such a resistance mechanism.