Penicillin-binding proteins (PBPs) are enzymes responsible for the polymerization of the glycan strand and the cross-linking between glycan chains as well as the target proteins for β-lactam antibiotics. Mutational alterations in PBPs can confer resistance either by reducing binding of the antibiotic to the active site or by evolving a β-lactamase activity that degrades the antibiotic. As no sy...

Nonreducible cystine isosteres represent important peptide design elements in that they can maintain a near-native tertiary conformation of the peptide while simultaneously extending the in vitro and in vivo half-life of the biomolecule. Examples of these cystine mimics include dicarba, diselenide, thioether, triazole, and lactam bridges. Each has unique physicochemical properties that impact u...

Beta-lactam antibiotics are among the most important drugs used to fight bacterial infection. Overuse and misuse of beta-lactam antibiotics has caused the evolution of resistance mechanisms, allowing pathogenic bacteria to survive antibiotic treatment. The major source of resistance to beta-lactam antibiotics occurs through production of enzymes called beta-lactamases capable of catalyzing hydr...

The [c-lactam] derivative of cobalamin antagonizes vitamin B12 in vivo. Therefore, we investigated its effects in tissue culture to develop a model in which to study vitamin B12-deficient hemopoiesis. HL60 cells were cultured in medium containing either methionine or L-homocysteine thiolactone, and various concentrations of 5-methyltetrahydrofolate or pteroylglutamic acid. In medium with L-homo...

In some enterobacterial pathogens, but not in Escherichia coli, loss-of-function mutations are a common route to clinically relevant beta-lactam antibiotic resistance. We previously constructed an assay system for studying enterobacterial beta-lactam resistance mutations using the well-developed genetics of E. coli by integrating enterobacterial ampRC genes into the E. coli chromosome. Like the...

INTRODUCTION .......................................................................................................................................................547 GENERAL ASPECTS OF b-LACTAM COMPOUNDS........................................................................................548 BIOSYNTHESIS OF PENICILLINS AND CEPHALOSPORINS: AN OUTLINE.............................................

BACKGROUND Studies on the association between antibiotic treatment and outcomes in outpatients with chronic obstructive pulmonary disease (COPD) and pneumonia are scarce. This study aimed to evaluate the effectiveness of fluoroquinolones and β-lactam/β-lactamase inhibitors for pneumonia in COPD outpatients. METHODS We conducted a retrospective cohort study and identified 4,851 episodes of pne...

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is a worldwide health concern. The world health organization in its 2017 tuberculosis report states, “TB is the ninth leading cause of death worldwide and the leading cause from a single infectious agent, ranking above HIV/AIDS” [1-3]. The failure to control TB is due to the emergence of Mtb strains that are resistant to first line ...

-lactamases are a major cause of resistance to the -lactam antibiotics. Many classes of -lactamases have been described depending on substrate specificity and susceptibility to inhibitors [1]. Amp C -lactamases are able to hydrolyse all penicillins and cephalosporins and are not inhibited by clavulanic acid. Bacteria that produce these enzymes are resistant to all penicillins including lac...

This study compares beta-lactam and vancomycin among intravenous drug users with infective endocarditis caused by methicillin-susceptible Staphylococcus aureus. Patients who received vancomycin had higher infection-related mortality, even if they were switched to beta-lactam once culture results became available; this relationship persisted after logistic regression analysis controlling for cli...