[Extended-spectrum beta-lactamases: their role in clinical microbiology laboratory, treatment and infection control]

The major mechanism responsible for resistance to beta-lactam antibiotics is the production of beta-lactamases. These enzymes, which have the ability to inactivate extended-spectrum beta-lactam antibiotics, like cefotaxime and ceftazidime are called as extended-spectrum beta-lactamases (ESBL). The most important pathogen which produces beta-lactamases among Gram positive bacteria is Staphylococcus aureus and the members of the Enterobacteriaceae family are the leading beta-lactamase producing organisms among Gram negative bacteria. Although the beta-lactamase inhibitors like clavulanic acid, sulbactam and tazobactam could block ESBL effects, ESBL's have still been considered as a threat since they are coded by plasmids and can easily be transmitted between species. Recently, more than 150 ESBLs have been identified. Numerous methods have been proposed for the detection of ESBLs in clinical isolates. Imipenem seems to be the most effective agent for the therapy and control of the spread of infections caused by ESBL-producing bacteria. In this review article, the roles of ESBL in clinical microbiology laboratory, treatment and infection control, have been discussed.