Extended Spectrum Beta- Lactamases: A Minireview of Clinical Relevant Groups

Extended spectrum beta-lactamases are enzymes that hydrolyze the beta-lactam ring of Beta-lactam antibiotics rendering the organism resistant. ESBL prevalence is still increasing across the globe and have been implicated in hospital acquired infections and complicated urinary tract infections in Canada. TEM, SHV and CTX-M are becoming more common with CTX-M becoming more of importance as it is associated with complicated urinary tract infections. A variety of detection methods can be used including phenotypical methods, molecular methods and automated methods. Several automated instruments are commercially available to detect phenotypic resistance, recently the Clinical Laboratory Standards Institute has altered their breakpoints negating the necessity to perform confirmatory tests. Unfortunately not all of the commercial panels have the ability to detect lower breakpoints. Due to the importance of ESBL producing organisms in both hospital and community acquired infections, the associated increase in cost treating this infections and expanding spread across the globe, there is a need for further research into these enzymes.