Background and Aims: The rate of urinary tract infection caused by the extended-spectrum-β-lactamase- (ESBL) producing Escherichia coli (E. coli) is increasing worldwide. This study aimed to assess the frequency of blaCTX-M genes in the E. coli isolated from urinary tract infection (UTI) in outpatients. Methods: 240 E. coli bacteria were isolated from the outpatients’ urine samples in the Kerma...

A variety of novel tetrazole derivatives attached to the β-lactam ring was made utilizing heptanitrile in a reaction with generated azide-β-lactam derivatives, and these compounds were then studied using IR NMR spectroscopy. Biological testing showed that most final good antibacterial antifungal activity, particularly derivative (b3), which shown efficacy on par or even superior reference drugs...

Penicillin binding proteins (PBPs) are involved in peptidoglycan synthesis, and their inactivation is linked to β-lactamase expression in ampR-β-lactamase module-harboring Gram-negative bacteria. There are seven annotated PBP genes, namely, mrcA, mrcB, pbpC, mrdA, ftsI, dacB, and dacC, in the Stenotrophomonas maltophilia genome, and these genes encode PBP1a, PBP1b, PBP1c, PBP2, PBP3, PBP4, and ...

Abstract Background Ceftazidime-avibactam (CAZ-AVI) is a β-lactam/non-β-lactam β-lactamase inhibitor combination that can inhibit class A, C, and some D β-lactamases. Resistance caused by these β-lactamases often results in multidrug-resistance (MDR). This study evaluated the vitro activity of CAZ-AVI comparators against MDR Enterobacterales Pseudomonas aeruginosa isolates collected from patien...

Mycobacterium tuberculosis (M. tuberculosis) is considered innately resistant to β-lactam antibiotics. However, there is evidence that susceptibility to β-lactam antibiotics in combination with β-lactamase inhibitors is variable among clinical isolates, and these may present therapeutic options for drug-resistant cases. Here we report our investigation of susceptibility to β-lactam/β-lactamase ...

Previous studies showed that sub-MIC levels of β-lactam antibiotics stimulate biofilm formation in most methicillin-resistant Staphylococcus aureus (MRSA) strains. Here, we investigated this process by measuring the effects of sub-MIC amoxicillin on biofilm formation by the epidemic community-associated MRSA strain USA300. We found that sub-MIC amoxicillin increased the ability of USA300 cells ...

The target of β-lactam antibiotics is the D,D-transpeptidase activity of penicillin-binding proteins (PBPs) for synthesis of 4→3 cross-links in the peptidoglycan of bacterial cell walls. Unusual 3→3 cross-links formed by L,D-transpeptidases were first detected in Escherichia coli more than four decades ago, however no phenotype has previously been associated with their synthesis. Here we show t...

Heteroresistance to penicillin in Streptococcus pneumoniae is the ability of subpopulations to grow at a higher antibiotic concentration than expected from the MIC. This may render conventional resistance testing unreliable and lead to therapeutic failure. We investigated the role of the primary β-lactam resistance determinants, penicillin-binding protein 2b (PBP2b) and PBP2x, and the secondary...