Abstract
Background and Objectives: Extended –spectrum - lactamase (ESBL) producing bacteria have been detected worldwide. Production of these enzymes by bacteria often causes resistance to a wide variety of antibacterial drugs. Infection with this kind of bacteria has been life threatening, especially among patients in intensive care unit(ICU). In this study, the prevalence and plasmid profiles of ESBL producing Enterobacteriaceae isolated in Children hospital of Tabriz has been studied. A better knowledge of ESBL prevalence rate can lead to a more effective treatment strategy.
Materials and Methods: Antibacterial susceptibility tests for the isolated bacteria were carried out according to Kirby& Bauer disk diffusion method. Strains were then screened for ESBL production by double disk and combined test methods followed by MIC determination with E-test. The plasmids of the ESBL producing isolates were extracted by alkaline lysis method. Electrophoresis of the purified plasmids were performed in 0.8% agarose gel. Overnight incubation at 44 ◦C was used for plasmid elimination.
Results: All of the Pseudomonas aeruginosa and Enterobacter cloacae isolates and 90.9% of Klebsiella pneumoniae strains isolated from the ICU residing patients by E-test were shown to be ESBL- producers. Plasmid profiles of the isolated bacteria revealed five distinct clonal types.
Conclusion: Selective pressure due to excessive antibiotic therapy often results in ESBL prevalence. Our results indicated that the ESBL enzymes belonged to the CTX-M and AmpC group. Further molecular studies are needed.