BLAD ß-Lactmase Database
A comprehensive database of widely circulated ß-Lactamases
Welcome to ß-Lactamase
Beta-lactamases are enzymes produced by some bacteria and are responsible for their resistance to beta-lactam antibiotics like penicillins, cephamycins, and carbapenems (ertapenem) (Cephalosporins are relatively resistant to beta-lactamase). These antibiotics have a common element in their molecular structure: a four-atom ring known as a beta-lactam.
CTX-M beta-lactamase (Class A)
CTX-M beta-lactamases (class A)These enzymes were named for their greater activity against cefotaxime than other oxyimino-beta-lactam substrates (e.g., ceftazidime, ceftriaxone, or cefepime). Rather than arising by mutation, they represent examples of plasmid acquisition of beta-lactamase genes normally found on the chromosome of Kluyvera species, a group of rarely pathogenic commensal organisms. These enzymes are not very closely related to TEM or SHV beta-lactamases in that they show only approximately 40% identity with these two commonly isolated beta-lactamases. More than 80 CTX-M enzymes are currently known. Despite their name, a few are more active on ceftazidime than cefotaxime. They have mainly been found in strains of Salmonella enterica serovar Typhimurium and E. coli, but have also been described in other species of Enterobacteriaceae and are the predominant ESBL type in parts of South America. (They are also seen in eastern Europe) CTX-M-14, CTX-M-3, and CTX-M-2 are the most widespread. CTX-M-15 is currently (2006) the most widespread type in E. coli the UK and is widely prevalent in the community.
Beta-lactam antibiotics are typically used to treat a broad spectrum of Gram-negative bacteria. Beta-lactamases produced by Gram-negative organisms are usually secreted.
Sequence presentation by:
Copyright © 2012 Dr. Asad U Khan All rights reserved
Interdisciplinary Biotechnology Unit
Aligarh Muslim University, Aligarh-202001
Uttar Pradesh, India