BLAD ß-Lactmase Database
A comprehensive database of widely circulated ß-Lactamases
Welcome to ß-Lactmase
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.
OXA beta-lactamase (Class D)
OXA beta-lactamase (class D)OXA beta-lactamases were long recognized as a less common but also plasmid-mediated beta-lactamase variety that could hydrolyze oxacillin and related anti-staphylococcal penicillins. These beta-lactamases differ from the TEM and SHV enzymes in that they belong to molecular class D and functional group 2d . The OXA-type beta-lactamases confer resistance to ampicillin and cephalothin and are characterized by their high hydrolytic activity against oxacillin and cloxacillin and the fact that they are poorly inhibited by clavulanic acid. Amino acid substitutions in OXA enzymes can also give the ESBL phenotype. While most ESBLs have been found in E. coli, K. pneumoniae, and other Enterobacteriaceae, the OXA-type ESBLs have been found mainly in P. aeruginosa. OXA-type ESBLs have been found mainly in Pseudomonas aeruginosa isolates from Turkey and France. The OXA beta-lactamase family was originally created as a phenotypic rather than a genotypic group for a few beta-lactamases that had a specific hydrolysis profile. Therefore, there is as little as 20% sequence homology among some of the members of this family. However, recent additions to this family show some degree of homology to one or more of the existing members of the OXA beta-lactamase family. Some confer resistance predominantly to ceftazidime, but OXA-17 confers greater resistance to cefotaxime and cefepime than it does resistance to ceftazidime.
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