lunes, 19 de agosto de 2013

Characterization of Cephalosporinases Produced by Clinical Isolates of Enterobacteriacae in North Lebanon

Background: The problem of Enterobacteriacae resistance to β-Lactamase drugs is of growing concern in hospitals. Enterobacteria have developed multiple mechanisms of resistance to antibiotics, the main one is the enzymatic resistance mediated by the beta-lactamases. This study aims to characterize the occurrence of cephalosporinases in clinical isolates of Enterobacteriacae isolates in North Lebanon. Methods. Twenty two strains of Enterobacteriacae producing high level of cephalosporinases have been studied. The antibiotic susceptibility of each strain was tested on Mueller Hinton agar contains cloxacilline (250 mg/L) and by using E-test according the guidelines of the Antibiogram Committee of the French Society for Microbiology. The search for plasmid-mediated cephalosporinases was performed using PCR and primers for plasmid-mediated cephalosporinases genes (CMY-2, DHA-1, ACT-1, ACC-1, FOX-1 and MOX-1). Results: Thirteen positive strains were detected, of these 9 strains produced the plasmid-mediated cephalosporinase (CMY-2) and one strain produced the plasmidmediated cephalosporinase (DHA-1). The remaining 9 strains were high-level chromosomal cephalosporinase producers since they belong to group-three Enterobacteria. They did neither produce plasmid-mediated cephalosporinase, nor did they have resistance to third generation cephalosporins except for cefepim. Two strains (CMUL E. coli 021) and CMUL E. coli 255) which were not susceptible for cefepim by E-test produced plasmid-mediated cephalosporinase The sequencing result of these 2 E.coli strains did not show any mutation in the promoter that is responsible for high expression level of the chromosomal cephalosporinase. All examined strains producing plasmid-mediated cephalosporinase CMY-2 were analyzed by ERIC-PCR technique. The results showed that two of these strains had the same pattern (C4 and C5) and three others had another pattern (C10, C12 and C13). Conclusion: This study shows the variations of cephalosporinases produced by clinical isolates of Enterobacteriacae in North Lebanon.

via Scribd Feed for iMedPub

No hay comentarios:

Publicar un comentario