BACKGROUND The substitution of piperacillin/tazobactam, ampicillin/sulbactam, or both for third-generation cephalosporins has been associated with reduced vancomycin-resistant enterococci (VRE). However, piperacillin/tazobactam came into widespread use during a period in which the prevalence of VRE increased. We hypothesized that the increasing use of piperacillin/tazobactam and other agents wi...

A class of methicillin-resistant Staphylococcus aureus strains shows vancomycin resistance in the presence of beta-lactam antibiotics (beta-lactam-induced VAN-resistant methicillin-resistant S. aureus [BIVR]). Two possible explanations may be offered: (i) vancomycin in culture medium is depleted, and (ii) the D-Ala-D-Ala terminal of the peptidoglycan network is replaced with D-Ala-D-lactate. We...

During an island-wide PCR-based surveillance study of beta-lactam resistance in multidrug-resistant (MDR) Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter calcoaceticus-baumannii complex isolates obtained from 17 different hospitals, 10 KPC-positive Acinetobacter isolates were identified. DNA sequencing of the bla(KPC) gene identified KPC-2, -3, and -4 and a no...

The incidence of community-associated, healthcare-associated, and hospital-acquired sterile-site infections due to methicillin-resistant Staphylococcus aureus (MRSA) isolates and the susceptibility of the isolates to non- beta -lactam antibiotics were evaluated for 549 hospitalized patients during a 3-year period. The incidence of community-associated MRSA infection increased significantly. The...

Susceptibilities of 98 clinical isolates of Pseudomonas aeruginosa, including 33 strains with known mechanisms of amikacin resistance, were tested by the agar dilution method against 10 beta-lactam drugs. Ceftazidime, imipenem, and cefsulodin had the greatest activity, regardless of the aminoglycoside susceptibilities. The strains which were highly resistant to amikacin appeared to be less susc...

Lactivicin (LTV) is a natural non-beta-lactam antibiotic that inhibits penicillin-binding proteins and serine beta-lactamases. A crystal structure of a BS3-LTV complex reveals that, as for its reaction with PBPs, LTV reacts with the nucleophilic serine and that cycloserine and lactone rings of LTV are opened. This structure, together with reported structures of PBP1b with lactivicins, provides ...

The in vitro activities of four new beta-lactam antimicrobial agents (moxalactam, cefotaxime, cefoperazone, and piperacillin) and the aminoglycosides against 744 recent clinical isolates of facultative gram-negative bacilli were compared simultaneously by the agar dilution method. The major in vitro difference of these newer beta-lactam compounds appeared to be their antipseudomonal activity; c...

A rapid and specific high-performance liquid chromatography method with UV detection (HPLC-UV) for the simultaneous determination of 12 beta-lactam antibiotics (amoxicillin, cefepime, cefotaxime, ceftazidime, ceftriaxone, cloxacillin, imipenem, meropenem, oxacillin, penicillin G, piperacillin, and ticarcillin) in small samples of human plasma is described. Extraction consisted of protein precip...

Previous studies in this and other laboratories have shown that derepression of beta-lactamases in strains of Enterobacter and Pseudomonas spp. is responsible for the rapid development of resistance to a variety of beta-lactam antibiotics. The purpose of the current study was to evaluate the effects of clindamycin on derepression of beta-lactamases in these two genera. In tests with four strain...

Enterobacteriaceae species are important human pathogens while increasing number of antibiotic resistant strains are detected worldwide. The most common antibiotic resistance in Enterobacteriaceae is observed against beta-lactams, fluoroquinolones, aminoglycosides while recently resistance to polymyxins has also appeared. Beta-lactam resistance is mainly conferred by beta-lactamases, capable to...