ESBL

Extended-spectrum ß-Lactamases (ESBLs) are extremely broad spectrum ß-Lactamase enzymes found in a variety ofEnterobacteriaceae. Most strains producing these ß-Lactamases are Klebsiella pneumoniae, other Klebsiella species (i.e., K. oxytoca), and Escherichia coli. When producing these enzymes, organisms become highly effective at inactivating various ß-Lactam antibiotics.


 these organisms are resistant to all ß-Lactam antibiotics except cephamycins (cefoxitin, cefotetan) and carbapenems. In addition, ESBL-producing organisms are frequently resistant to many other classes of antibiotics, including aminoglycosides and fluoroquinolones.^[2-4]Hence, a more appropriate name would be "multidrug resistant organisms."


The initial approach to assessing the presence of ESBL isolates in an institution should involve examining the susceptibility of K. pneumoniae and E. coli to ceftazidime. If susceptibilities to ceftazidime are less than 100%, ESBL-producing organisms are probably present. 

Conclusions

The ESBL-producing organisms are a breed of multidrug-resistant pathogens that are increasing rapidly and becoming a major problem in the area of infectious diseases. High rates of third-generation cephalosporin use have been impli-cated as a major cause of this problem. Problems associated with ESBLs include multidrug resistance, difficulty in detection and treatment, and increased mortality. Of all available anti-microbial agents, carbapenems are the most active and reliable treatment options for infections caused by ESBL isolates. However, overuse of carbapenems may lead to resistance of other gram-negative organisms. Therefore, restricting the use of third-generation cephalo-sporins, along with implementation of infection control measures, are the most effective means of con-trolling and decreasing the spread of ESBL isolates.