Gohar Zaman, Karamat Ahmed Karamat, Shahid A Abbasi, Shahid Rafi, Aamir Ikram.
Prevalence of Extended-Spectrum Beta Lactamase (ESBL) producing Enterobacteriaceae in Nosocomial isolates.
Pak Armed Forces Med J Jan ;49(2):91-6.

Beta-lactamases of Gram-negative bacteria are the most important mechanism of resistance against Beta-lactam drugs. Two types of B-lactamases can confer resistance against 3rd generation cephalosporins; inducible chromosomal Beta-lactamases of Enterobacteriaceae, which are not inhibited by clavulanic acid and plasmid-mediated Beta-lactamases, which are inhibited by clavulanic acid. The latter are called extended spectrum Beta-lactamases (ESBLs). ESBLs can confer resistance against all [3-lactam drugs except carbapenem and cephamycin. <p> A study was carried out through March to August 1997 at the Armed Forces Institute of Pathology, Rawalpindi, to find out the prevalence of extended spectrum P-lactamase producing Enterobacteriaceae (ESBLPE) among nosocomial isolates. Two hundred nosocomial isolates were included in the study. After isolation and identification to the species level, these isolates were tested for the production of ESBLs by using double disc diffusion technique. Prevalence of ES13Ls in Enterobacteriaceae was found to be 35%. Highest prevalence was seen in Klebsiella pneumoniae followed by Enterobacter cloacae and Escherichia coli. Prevalence in other species was much less. Considering the high prevalence of ESBLs in nosocomial isolates, it is suggested that all such isolates should be tested for the production of ESBLs in the routine microbiology laboratory.

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