BACKGROUND & OBJECTIVES AmpC β-lactamases are clinically significant since these confer resistance to cephalosporins in the oxyimino group, 7-α methoxycephalosporins and are not affected by available β-lactamase inhibitors. In this study we looked for both extended spectrum β-lactamases (ESBL) and AmpC β-lactamases in Klebsiella pneumoniae clinical isolates. METHODS One hundred consecutive, n...

Background/Aim. Sometimes resistance of Pseudomonas aeruginosa (Ps. aeruginosa) is developed during antibiotic treatment, in spite of the initial susceptibility in vitro. The aim of this study was to use an in vitro model for the study of the development of resistant strains of Ps. aeruginosa after a short exposure to ceftazidime, and to study the hydrolysing capacity of β-lactamases produced b...

background: the increasing pattern of multi-drug resistant (mdr) bacteria has limited therapeutic options especially for nosocomial isolates of klebsiella pneumoniae. therefore, the aim of this study was the molecular detection of 16s rrna methylase and blactx-m-15 among k. pneumoniae strains isolated from hospitalized patients in mofid, imam hossein and taleghani hospitals. materials and metho...

b ackground: in recent decades, extended spectrum beta-lactamase (esbl) producing bacteria have increased worldwide. the most important causative agents of nosocomial infections throughout the world, escherichia coli and klebsiella pneumoniae as main esbl-producing bacteria are so highly regarded. trends  in  the  treatment  of  infections  by such  bacteria  have  led  to  a  global concern. t...

Most methicillin-resistant Staphylococcus aureus (MRSA) strains produce beta-lactamase. To determine whether this enzyme(s) is identical to one or more of the four beta-lactamases produced by methicillin-susceptible strains, the beta-lactamases of 50 MRSA isolates were typed by using substrate profile analysis. Forty type A, no type B, ten type C, and no type D beta-lactamase-producing strains ...

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...