CTX-M-19 is a recently identified ceftazidime-hydrolyzing extended-spectrum beta-lactamase, which differs from the majority of CTX-M-type beta-lactamases that preferentially hydrolyze cefotaxime but not ceftazidime. To elucidate the mechanism of ceftazidime hydrolysis by CTX-M-19, the beta-lactam MICs of a CTX-M-19 producer, and the kinetic parameters of the enzyme were confirmed. We reconfirme...

BACKGROUND Previous studies indicate that vancomycin is inferior to beta-lactams for treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections. However, it is unclear if this association is true for empiric and definitive therapy. Here, we compared beta-lactams with vancomycin for empiric and definitive therapy of MSSA bloodstream infections among patients admitte...

The activity of daptomycin (DAP) against methicillin-resistant Staphylococcus aureus (MRSA) is enhanced in the presence of β-lactam antibiotics. This effect is more pronounced with β-lactam antibiotics that exhibit avid binding to penicillin binding protein 1 (PBP1). Here, we present evidence that PBP1 has a significant role in responding to DAP-induced stress on the cell. Expression of the pbp...

The use of therapeutic drug monitoring (TDM) to optimize beta-lactam dosing in critically ill patients is growing in popularity, although there are limited data describing the potential impact of altered protein binding on achievement of target concentrations. The aim of this study was to compare the measured unbound concentration to the unbound concentration predicted from published protein bi...

We have examined bacterial determinants that influence beta-lactam activity in Haemophilus influenzae cells cultivated in a system that reproduces in vivo growth conditions. Bacteria grown in diffusion chambers were recovered from the peritoneal cavities of rats, and their cell properties were compared with those of bacteria grown in broth cultures by various tests performed in vitro. The rate ...

BACKGROUND Beta-lactamase production and porin decrease are the well-recognized mechanisms of acquired beta-lactam resistance in Klebsiella pneumoniae isolates. However, such mechanisms proved to be absent in K. pneumoniae isolates that are non susceptible to cefoxitin (FOX) and susceptible to amoxicillin+clavulanic acid in our hospital. Assessing the role of efflux pumps in this beta-lactam ph...

Abstract We report a case of an unusually located site acute localized exanthematous pustulosis in the right lower limb patient treated with beta‐lactams which resolved upon cessation. This highlights need for vigilance as well index suspicion atypical presentations.

Several monocyclic ?-lactams have been synthesized via a [2+2] ketene–imine cycloaddition reaction (Staudinger reaction) and evaluated for their biological activities. The structure of products was confirmed by spectral data elemental analyses. ?-Lactams 4 b h exhibited 31 27 anti-inflammatory ratios, respectively, which are as well the well-known dexamethasone corticosteroid with 32 ratio. two...

Minimum inhibitory concentrations of seven new beta-lactam derivatives were determined against 35 isolates of Yersinia enterocolitica. Ceftizoxime and ceftriaxone were the most active of the antimicrobial agents tested.

Homo-cysteinyl peptides were found to be more active than cysteinyl peptides toward L1 metallo-beta-lactamase as reversible competitive inhibitors. A combinatorial library of more than 90 homo-cysteinyl peptides was synthesized and screened for their inhibitory activity toward the L1 enzyme. A systematic structure-activity relationship analysis has revealed the preferred interaction groups for ...