The rates of occurrence of metallo-beta-lactamase-mediated resistances in Pseudomonas aeruginosa, Acinetobacter species, and Serratia marcescens, among other gram-negative bacilli, have escalated since 2000, severely limiting treatment options in Asia, Europe, and Latin America to non-beta-lactam antimicrobial classes. Clinical isolates harboring metallo-beta-lactamases have also recently been ...

Background: Metallo-β-lactamases (MBLs) have been reported in gram negative bacilli and are becoming increasingly important clinically because the enzymes hydrolyse almost all β-lactams, including carbapenems. Thus, the present study was conducted to determine the prevalence of MBL types in imipenem-nonsusceptible Pseudomonas aeruginosa and Acinetobacter baumannii isolated from a tertiary teach...

Various inhibitors of metallo-beta-lactamases have been reported; however, none are effective for all subgroups. Those that have been found to inhibit the enzymes of subclass B2 (catalytically active with one zinc) either contain a thiol (and show less inhibition towards this subgroup than towards the dizinc members of B1 and B3) or are inactivators behaving as substrates for the dizinc family ...

Multidrug resistance has been increasing among Gram-negative bacteria and is strongly associated with the production of both chromosomal- and plasmid-encoded beta-lactamases, whose number now exceeds 890. Many of the newer enzymes exhibit broad-spectrum hydrolytic activity against most classes of beta-lactams. The most important plasmid-encoded beta-lactamases include (a) AmpC cephalosporinases...

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...

A total of 209 clinical isolates of Pseudomonas (193 Pseudomonas aeruginosa, 10 P. putida, 4 P. stutzeri, and 2 P. fluorescens isolates) with reduced susceptibilities to imipenem and/or ceftazidime were subjected to PCR assays with primers specific for bla(IMP-1), bla(IMP-2), bla(VIM-1), and bla(VIM-2) and sequence analysis to identify the metallo-beta-lactamases (MBLs) prevalent among these or...

A series of mercaptoacetic acid thiol esters have been identified as metallo-beta-lactamase inhibitors. Electrospray mass spectrometry (ESMS) has shown that irreversible inhibition of the Bacillus cereus II metallo-beta-lactamase by SB214751, SB214752, and SB213079 was concomitant with a 90-Da increase in mass of the enzyme. Tryptic digestion of the B. cereus II inhibited with SB214751 illustra...

The mechanisms responsible for reduced susceptibility to imipenem (MIC 2-16 mg/L) were investigated in eight strains of Bacteroides fragilis. All the strains produced elevated levels of beta-lactamase. Four B. fragilis strains produced metallo-beta-lactamase capable of marked imipenem hydrolysis, and these enzymes were shown to be responsible for resistance. There was evidence, from testing sus...