Acidaminococcus fermentans belongs to the group of strictly anaerobic gram-negative cocci. All previously described Acidaminococcus strains are susceptible to beta-lactam antibiotics. An A. fermentans strain (RYC-MR95) resistant to penicillin and expanded-spectrum cephalosporin (amoxicillin and cefotaxime MICs, 64 microgram/ml) was isolated from a human perianal abscess. A fragment encoding a b...

The beta-lactamases produced by Acinetobacter lwoffii ULA-501, Acinetobacter baumannii ULA-187, and A. baumannii AC-14 strains were purified and characterized, and their kinetic interactions with several beta-lactam molecules, including substrates and inhibitors, were studied in detail. The three enzymes appeared to be cephalosporinases with different acylation efficiencies (kcat/Km ratio value...

Beta-lactamases are a superfamily of enzymes which degrade the β-lactam class of antibiotics. They are produced endogenously by the bacterial cells, which when exposed to the β-lactam class of antibiotics inactivate them by cleaving the β-lactam ring. Based on the presence or absence of metallic ligand, β-lactamases have been divided into two broad functional classes. β-Lactamases are a constit...

Routine detection of AmpC beta lactamases in Escherichia coli is cumbersome. This study was performed to determine the usefulness of a modified disc diffusion test to detect AmpC beta lactamases in E.coli. 28 non-repetitive, cefoxitin resistant isolates of E.coli were collected from cases of urinary tract infections and screened phenotypically for ESBLs and AmpC beta lactamase using DDST (cefta...

Microbial drug resistance is a growing problem of global magnitude. In gram-negative pathogens, the most important resistance problems are encountered in Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter, with increasing trends observed for all major anti-gram-negative agents (beta-lactams, fluoroquinolones and aminoglycosides). A matter of major concern is the emergence of new beta-...

The modified Hodge method (MHT) has been recommended by the CLSI for confirmation of suspected class A carbapenemase production in species of Enterobacteriaceae. This test and the Masuda method (MAS) have advantages over traditional phenotypic methods in that they directly analyze carbapenemase activity. In order to identify the potential interferences of these tests, we designed a panel compos...

BACKGROUND AND PURPOSE Data on the epidemiology of OXA-type extended-spectrum beta (beta)-lactamases (ESBLs) are limited due to difficulty of identification by routine microbiology laboratories. We determined the prevalence rate of OXA-type beta-lactamases among extended-spectrum cephalosporin (ESC)-non-susceptible Pseudomonas aeruginosa isolates at a university hospital in southern Taiwan. M...

OBJECTIVES Pseudomonas aeruginosa is a major causative agent of hospital infections. The purpose of this study was to determine the antibiotic susceptibility of P. aeruginosa in a French multicentre study and to investigate the mechanisms of beta-lactam resistance. METHODS Four hundred and fifty non-repetitive strains of P. aeruginosa were collected in 15 French university hospitals in 2004. ...

AIM To characterize AmpC-beta lactamases among Enterobacteriaceae isolates from clinical samples at Mbarara Regional Referral Hospital. STUDY DESIGN Laboratory-based descriptive cross-sectional study. PLACE AND DURATION OF STUDY Microbiology Department, Mbarara Regional Referral Hospital and MBN clinical Laboratories, between May to September 2013. METHODOLOGY This study included 293 Ente...

OBJECTIVES The aim of this study was to characterize the KPC-type carbapenem-hydrolysing beta-lactamase, extended-spectrum beta-lactamases (ESBLs) and class 1 integrons among nosocomial Klebsiella pneumoniae isolated in Rio de Janeiro, Brazil. METHODS MICs were determined and isolates were screened for ESBLs, metallo-beta-lactamases (MBLs) and class A carbapenemase-producing phenotypes. The m...