The production of β-lactamase enzymes is the main mechanism of resistance to β-lactam antibiotics in gramnegative bacilli. Therefore, it is important to identify the β-lactamases-producing bacteria for the treatment of caused infections. This article aimed to review the recent literature and guidelines regarding phenotypic detection of β-lactamases in common gram-negative bacilli in clinical sa...

The Class D β-lactamases have emerged as a prominent resistance mechanism against β-lactam antibiotics that previously had efficacy against infections caused by pathogenic bacteria, especially by Acinetobacter baumannii and the Enterobacteriaceae. The phenotypic and structural characteristics of these enzymes correlate to activities that are classified either as a narrow spectrum, an extended s...

Background & Aims: Imipenem is a member of Carbapenem with stability against most -lactamases .It is of particular use in the treatment of infections associated with drug resistant gram negative bacteria harboring ESBL and AmpC genes. The aim of this study was to determine the imipenem resistance in gram negative bacteria causing nosocomial infections and the presence of metallo--lactamases (MB...

BACKGROUND Resistance among Klebsiella pneumoniae to most antibiotics is on the rise. Tigecycline has been considered as one of the few therapeutic options available to treat multidrug-resistant bacteria. We investigated the clinical and microbiological characteristics of tigecycline non-susceptible K. pneumoniae bacteremia. METHODS Adult patients with tigecycline non-susceptible K. pneumonia...

The detection of class A serine-carbapenemases among species of Enterobacteriaceae remains a challenging issue. Methods of identification for routine use in clinical microbiology laboratories have not been standardized to date. We developed a novel screening methodology suitable for countries with high basal levels of carbapenem resistance due to non-carbapenemase-mediated mechanisms and standa...

The TEM-1 and SHV-1 beta-lactamases are important contributors to resistance to beta-lactam antibiotics in gram-negative bacteria. These enzymes share 68% amino acid sequence identity and their atomic structures are nearly superimposable. Extended-spectrum cephalosporins were introduced to avoid the action of these beta-lactamases. The widespread use of antibiotics has led to the evolution of v...

The expression of resistance to cephalosporins is highly varied and due to various mechanisms. The greatest disadvantage of the cephalosporins is that they are inactivated by the array of beta-lactamases produced by bacteria. The high levels of chromosomal enzymes produced by these organisms are a major cause of cephalosporin resistance. Plasmid-mediated beta-lactamases (PMBLs) have also been i...