CTX-M-15 extended-spectrum beta-lactamases in Enterobacteriaceae in the intensive care unit of Tlemcen Hospital, Algeria.

The aim of this study was to detect extended-spectrum beta-lactamases (ESBL) in Enterobacteriaceae isolates in the intensive care unit (ICU) of Tlemcen hospital in north-western Algeria. Antimicrobial susceptibility testing, molecular typing, characterization of ESBL-encoding genes and the genetic environment, conjugation experiments and plasmid analysis were carried out. In all, 28 Enterobacteriaceae isolates were isolated from specimens recovered from patients in the ICU and 2 from surfaces of the unit. Of these, 11 isolates (4 Escherichia coli, 5 Klebsiella pneumoniae and 2 Enterobacter cloacae) produced ESBL of the CT-X-M-15 type. Molecular typing of the isolates showed the clonal nature of 4 K. pneumoniae isolates. The bla(CTXM-15) gene was genetically linked to insertion sequence lSEcp1B and was transferable by conjugation from 3 isolates. Regular monitoring of resistance mechanisms, the establishment of a prevention strategy, and more rational and appropriate use of antibiotics are needed.

CTX-M-15 extended-spectrum beta-lactamases in Enterobacteriaceae in the intensive care unit of Tlemcen hospital, Algeria

The aim of this study was to detect extended-spectrum beta-lactamases [ESBL] in Enterobacteriaceae isolates in the intensive care unit [ICU] of Tlemcen hospital in north-western Algeria. Antimicrobial susceptibility testing, molecular typing, characterization of ESBL-encoding genes and the genetic environment, conjugation experiments and plasmid analysis were carried out. In all, 28 Enterobacteriaceae isolates were isolated from specimens recovered from patients in the ICU and 2 from surfaces of the unit. Of these, 11 isolates [4 Escherichia coti, 5 Klebsiellapneumoniae and 2 Enterobacter cloacae] produced ESBL of the CT-X-M-15 type. Molecular typing of the isolates showed the clonal nature of 4 K, pneumonlae isolates. The bla[CTMX-15] gene was genetically linked to insertion sequence ISEcp1B and was transferable by conjugation from 3 isolates. Regular monitoring of resistance mechanisms, the establishment of a prevention strategy, and more rational and appropriate use of antibiotics are needed

Antibiotic susceptibility and mechanisms of beta-lactam resistance among clinical strains of Pseudomonas aeruginosa: first report in Algeria.

OBJECTIVE: Pseudomonas aeruginosa is a major causative agent of hospital infections. Studies on this subject being rare in Algeria, we determined the antibiotic susceptibility of P. aeruginosa and investigated the mechanisms of beta-lactam resistance and the spread of multidrug resistant strains in the university affiliated Hospital of Tlemcen (Algeria). DESIGN: One hundred and ninety-nine consecutive strains of P. aeruginosa were collected between November 2005 and February 2007. MICs of antibiotics were measured by the agar dilution method. The resistance mechanisms to beta-lactams were identified phenotypically or by molecular methods (isoelectrofocusing, PCR and sequencing). Strains expressing a secondary beta-lactamase were serotyped and genotyped (Random Amplified Polymorphic DNA). RESULTS: The proportion of susceptible isolates were: ticarcillin (56%), piperacillin-tazobactam (81%), ceftazidime (88%), cefepime (80%), aztreonam (64%), imipenem (65%), amikacin (83%), tobramycin (81%) and ciprofloxacin (97%) according to the French CASFM breakpoints. Resistance to beta-lactams was linked to the production of transferable beta-lactamases (16%), overproduction of cephalosporinase AmpC (12%) and/or non-enzymatic mechanisms such as the loss of porin OprD (35%) and overproduction of the active efflux system MexAB-OprM (24%). High level resistance to ticarcillin was due to the expression of beta- lactamase OXA-10 alone or associated with TEM-110. A genotypic analysis revealed the spread of a multidrug resistant epidemic clone expressing these two acquired beta-lactamases in the surgical ICU. CONCLUSIONS: This study shows that resistance to antibiotics, in particular to imipenem of P. aeruginosa, is becoming a cause of concern in the Hospital of Tlemcen.