background :    pseudomonas aeruginosa is a severe challenge for antimicrobial therapy, because of chromosomal mutations or exhibition of intrinsic resistance to various antimicrobial agents such as most β-lactams. we undertook this study to evaluate the existence of sme, aim and vim metallo-beta lactamases encoding genes among p. aeruginosa strains isolated from icu patients in al-zahra hospit...

background pseudomonas aeruginosa is an opportunistic pathogen mostly affecting hospitalized and immunodeficient patients. considering the extent of attention paid to the issue of antibiotic resistance and the origin of such resistance and the growing number of treatment failures in patients with burn injury, it seems that investigating the degree of ampc gene expression could be beneficial for...

BACKGROUND Proteus species cause a variety of community- and hospital-acquired illnesses. Synthesis of β-lactamases is the predominant mechanism for resistance to β-lactam antibiotics. Among the β-lactamases, extended spectrum β-lactamases (ESBLs) and AmpC β-lactamases are the most common. AIM The objective of this study was to determine the occurrence of ESBL and AmpC β-lactamases in Proteus...

β-Lactamases are the main cause of bacterial resistance to penicillins, cephalosporins and related β-lactam compounds. These enzymes inactivate the antibiotics by hydrolysing the amide bond of the β-lactam ring. Class A β-lactamases are the most widespread enzymes and are responsible for numerous failures in the treatment of infectious diseases. The introduction of new β-lactam compounds, which...

Klebsiella pneumoniae is a pathogen primarily capable of causing urinary tract infections and pneumonia in otherwise healthy people. Most of the strains are frequently resistant to numerous antibiotics, responsible for conferring multidrug resistance. This study was conducted to determine the prevalence of extended spectrum β-lactamases (ESBL), AmpC β-lactamases and metallo β-lactamases (MBL) a...

Environmental microorganisms represent the most relevant reservoir of resistance to antibiotics in the community, and this is due in part to the undue exposure of these organisms to antimicrobial agents. AmpC β-lactamases are clinically important cephalosporinases encoded on the chromosomes of bacteria in the Enterobacteriaceae family and some non-enteric bacteria including Pseudomonas aerugino...

An approach of using molinspiration calculations and molecular docking on PBPs (penicillin-binding proteins) and certain β-lactamases is employed to predict the molecular properties, bioactivity and resistance of newer and reference cephalosporins. The previously synthesized cephalosporins 1-8 and reference cephalosporins were subjected to extensive evaluations by calculating the molecular prop...

Bacterial beta-lactamases are the major causes of resistance to beta-lactam antibiotics. Three classes of these enzymes are believed to have evolved from ancestral penicillin-binding proteins (PBPs), enzymes responsible for bacterial cell wall biosynthesis. Both beta-lactamases and PBPs are able to efficiently form acyl-enzyme species with beta-lactam antibiotics. In contrast to beta-lactamases...

BACKGROUND Metallo-β-lactamases are bacterial enzymes that provide resistance to carbapenems, the most potent class of antibiotics. These enzymes are commonly encoded on mobile genetic elements, which, together with their broad substrate spectrum and lack of clinically useful inhibitors, make them a particularly problematic class of antibiotic resistance determinants. We hypothesized that there...

β-Lactamases threaten the clinical use of carbapenems, which are considered antibiotics of last resort. The classical mechanism of serine carbapenemase catalysis proceeds through hydrolysis of an acyl-enzyme intermediate. We show that class D β-lactamases also degrade clinically used 1β-methyl-substituted carbapenems through the unprecedented formation of a carbapenem-derived β-lactone. β-Lacto...