Background & objectives: Extended spectrum β-lactamases (ESBLs) are often plasmid mediated derived from mutations in the classic TEM and SHV genes by one or more amino acid substitution around the active site. Detection of TEM and SHV genes by molecular methods in ESBL producing bacteria and their pattern of antimicrobial resistance can provide useful information about its epidemiology and risk...

OBJECTIVES This study was conducted to analyse broad-spectrum cephalosporin-resistant Klebsiella oxytoca strains. METHODS The 57 isolates studied were recovered from clinical specimens (n=23) or from rectal swabs (n=34) during a 26-month period. Antibiotic susceptibility patterns were determined using standard agar diffusion and dilution methods including the synergy test between extended-spe...

GR69153, a new parenteral cephalosporin, inhibited 90% of Escherichia coli, Klebsiella oxytoca, Proteus mirabilis, Citrobacter diversus, shigellae, and salmonellae at less than 0.25 micrograms/ml (MIC90). It had activity comparable to those of ceftazidime, cefpirome, cefepime, and E-1040. Against cephalosporinase-producing Enterobacter cloacae, Citrobacter freundii, and Serratia marcescens, MIC...

OBJECTIVES Recently, resistance to extended-spectrum cephalosporins due to acquired beta-lactamases has been reported in Pseudomonas aeruginosa. The aim of this study was to investigate the prevalence of Ambler class A and D beta-lactamases and their extended-spectrum derivatives and antimicrobial susceptibilities of P. aeruginosa isolated from various parts of Korea. METHODS A total of 252 c...

The β-lactamases enzymes cleave the amide bond in β-lactam ring, rendering β-lactam antibiotics harmless to bacteria. In this communication we have studied structure-function relationship and phylogenies of class A, B and D beta-lactamases using structure-based sequence alignment and phylip programs respectively. The data of structure-based sequence alignment suggests that in different isolates...

Important discrepancies in isoelectric points (pI) of beta-lactamases were observed depending on the experimental procedure used for their determination: isoelectric focusing (IEF) in sucrose density gradients or analytical IEF in thin-layer polyacrylamide gels (PA). The variations, negligable in the case of TEM-like beta-lactamases, appeared to be important in the case of cephalosporinases and...

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 studied for susc...

Bacteria that simultaneously produce multiple extended-spectrum beta-lactamases are frequently isolated. We report an Enterobacter cloacae isolate, ES24, producing four different beta-lactamases (AmpC type beta-lactamase, TEM-1, SHV-7, and a novel extended-spectrum beta-lactamase, SHV-30). Direct sequencing of bla(SHV) gene products gave a "double peak" at position 703, suggesting the presence ...

BACKGROUND Pseudomonas aeruginosa remains a leading cause of severe wound infection and mortality in burn patients. OBJECTIVES The current study aimed to determine the prevalence of Ambler class A and D β-lactamases among P. aeruginosa isolated from infected burn injuries in Tehran, Iran. PATIENTS AND METHODS Bacteriological samples were taken from burn patients with clinical symptoms of bu...