Iftikhar Ahmed, Abdus Salam.
Extended spectrum beta-lactamases and bacterial resistance.
Pak J Med Sci Jan ;18(2):151-5.

In modern medical practice, newer antimicrobial drugs have been used extensively resulting in the emergence and rapid dissemination of resistant bacterial strains. Extended spectrum beta-lactamases (ESBLs) are enzymes that originate by mutations in genes for common plasmid mediated beta-lactamases such as TEM-1, TEM-2 and SHV-1 and are transmitted among bacterial species. Klebsiella sp. and E. coli are the two most frequently ESBLs producing bacteria worldwide with different degree of resistance in different countries. Resistance to third generation cephalosporins and susceptibility to beta-lactamase inhibitor compounds such as clavulanic acid, sulbactam and tazobactam are considered in favour of ESBL. These bacteria are considered resistant to all extended-spectrum penicillins, cephalosporins and monobactams but beta-lactamase-stable beta-lactam (e.g., imipenem) are active in vitro and also appear to be clinically effective. The genes that code for production of ESBLs are often linked to other resistance genes causing extended spectrum of drug resistance. Although different laboratory techniques to detect ESBL are available but there is no International consensus regarding its standardization. But general guidelines are advised to follow by the laboratories to detect ESBL on their own settings.

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