background :   ampc beta lactamases play a significant role in creating resistance to third generation cephalosporins worldwide. they mostly express on chromosome of enterobacteriaceae especially escherichia coli and cause consequential problem in clinical treatment and lead to failure in diagnosis and phenotypic test recommended by clinical and laboratory standards institute.   methods : total...

The Gram-positive bacterium B. cereus produces both -lactamase I, a class A serine enzyme, and -lactamase II, a zinc dependent enzyme of class B. Crystallographic studies of these two enzymes have shown that -lactamase I is homologous with the penicillin-sensitive D-alaD-ala carboxypeptidase-transpeptidase of Streptomyces R61 while -lactamase II has a hitherto unknown structure. New methods of ...

INTRODUCTION Infections caused by Pseudomonas aeruginosa are difficult to treat as the majority of isolates exhibit varying degrees of beta-lactamase mediated resistance to most of the beta-lactam antibiotics. It is also not unusual to find a single isolate that expresses multiple beta-lactamase enzymes, further complicating the treatment options. Thus the present study was designed to investig...

conclusions a high prevalence of multiple β-lactamase production was observed among the ampc producers (60%), of which the majority co-produced ampc and mbl. the current study results showed correlation between β-lactamase production and the presence of antibiotic resistance genes in the isolates. results all isolates were multidrug resistant. ampc, esbl and mbl production were observed in 35 (...

the nosocomial infections, caused by multi-drug resistant bacteria, are the most important cause of mortality throughout the world. one important mechanism against beta-lactam antibiotics is the production of beta-lactamases. enterobacteriaceae and non-fermentative bacteria, like pseudomonas aeruginosa and acinetobacter baumannnii may produce these enzymes. currently, there is no vaccine to pre...

Ceftazidime-resistant Klebsiella pneumoniae strains began to appear when ceftazidime usage was increased in two unrelated Chicago hospitals. These strains produced a beta-lactamase with an isoelectric point of 5.6 (RP-5.6) and strong hydrolyzing activity against ceftazidime. Two different restriction digest profiles were associated with the ceftazidime resistance plasmids. A second beta-lactama...

Definitions: Beta-lactam antimicrobials are characterized by having a four-membered cyclic amide (beta-lactam ring) as part of their chemical structure (Figure 1) [1]. This broad group includes the penicillins, cephalosporins, carbapenems, and monobactams [1]. All beta-lactams have a similar mechanism of action; they inhibit bacterial cell wall synthesis [1]. Resistance to beta-lactam antimicro...