Extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases produced by a clinical isolate of Klebsiella pneumoniae from chickens were detected with confirmatory phenotypic tests of the Clinical and Laboratory Standards Institute. The minimum inhibitory concentrations of 18 antibacterial drugs against K. pneumoniae were determined by the 2-fold microdilution method. The genotype and sub...

Using a nitrocefin competition assay, I determined the relative substrate affinity index (RSAI) values of nine clinically significant beta-lactamase enzymes against a range of beta-lactams. Using selected beta-lactam substrates, I observed large differences in the RSAI values of the nine enzymes that were sufficient in many cases to positively identify specific enzymes. I made use of the unique...

To determine the prevalence and genotype of an extended-spectrum beta-lactamase and new chromosomal AmpC beta-lactamases among clinical isolates of Enterobacter species, we performed antibiotic susceptibility testing, pI determination, induction tests, transconjugation, enterobacterial repetitive consensus (ERIC) PCR, sequencing, and phylogenetic analysis. Among the 51 clinical isolates collect...

BACKGROUND Knowledge of antimicrobial resistance patterns in E. coli, the predominant pathogen associated with urinary tract infections (UTI) is important as a guide in selecting empirical antimicrobial therapy. METHODS To describe the antimicrobial susceptibility of E. coli associated with UTI in a major university hospital in Tehran (Iran), seventy-six clinical isolates of E. coli were stud...

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...

Beta-lactamases continue to be the leading cause of resistance to beta-lactam antibiotics among gram-negative bacteria. In recent years there has been an increased incidence and prevalence of extended-spectrum beta-lactamases (ESBLs), enzymes that hydrolyze and cause resistance to oxyimino-cephalosporins and aztreonam. The majority of ESBLs are derived from the widespread broad-spectrum beta-la...

Salmonella spp. producing extended-spectrum beta-lactamases (ESBLs) have been reported in many countries, but there is no information on their prevalence in Africa. ESBL-producing Salmonella enterica serotype Isangi and S. enterica serotype Typhimurium strains have been noted in South Africa since 2001. A total of 160 consecutive isolates of Salmonella spp. were collected from 13 hospitals loca...

Diabetic foot ulcer (DFU) is a common and devastating complication in diabetes. Antimicrobial resistance mediated by extended-spectrum β-lactamases (ESBLs) production by bacteria is considered to be a major threat for foot amputation. The present study deals with the detection of Escherichia coli and the prevalence of bla(TEM), bla(SHV) and bla(OXA) genes directly from biopsy and swab of foot u...