Sixty-three strains of Haemophilus species, 38 of which were beta-lactamase producers (37 H. influenzae type b, 1 H. parainfluenzae) and 25 of which were beta-lactamase negative (20 H. influenzae, 5 H. parainfluenzae), were tested for susceptibility to cefoxitin, moxalactam (LY127935) (Lilly), cefsulodin (CGP 7174 E, Ciba), and cefoperazone (T 1551, Pfizer). Cefsulodin was relatively inactive a...

The stability to beta-lactamase hydrolysis of HR 756, a new cephalosporin antibiotic, was compared to the beta-lactamase stability of cefoxitin and cefuroxime. HR 756, cefoxitin, and cefuroxime were not hydrolyzed by Richmond type I, III, IV, and V beta-lactamases. Antibacterial activity of HR 756 correlated well with resistance to beta-lactamase hydrolysis except against Pseudomonas aeruginosa...

The specific activity, substrate profile, response to inhibitors, inducibility, and cellular localization of the beta-lactamase produced by an ampicillin-resistant strain of Haemophilus influenzae type B were investigated. In these properties the enzyme resembles beta-lactamases produced by other gram-negative bacilli more closely than those produced by gram-positive organisms. It is quite simi...

An Ambler class A β-lactamase gene, bla(CIA-1), was cloned from the reference strain Chryseobacterium indologenes ATCC 29897 and expressed in Escherichia coli BL21. The bla(CIA-1) gene encodes a novel extended-spectrum β-lactamase (ESBL) that shared 68% and 60% identities with the CGA-1 and CME-1 β-lactamases, respectively. bla(CIA-1)-like genes were detected from clinical isolates. In addition...

Four new beta-lactam antimicrobials, ceftriaxone, cefotiam, cefonicid, and mecillinam, were evaluated in vitro against 72 beta-lactamase-negative and 26 beta-lactamase-positive isolates of Neisseria gonorrhoeae. Ceftriaxone was the most active of the antimicrobials tested. It inhibited all isolates, regardless of beta-lactamase activity, at a concentration of less than or equal to 0.015 microgr...

The in vitro activities of three new beta-lactam antimicrobial agents, cefodizime, ceftazidime, and aztreonam (formerly azthreonam), were compared with those of cefotaxime, cefuroxime, cefoxitin, and penicillin against 100 beta-lactamase-negative and 42 beta-lactamase-positive Neisseria gonorrhoeae strains. The three new antimicrobial agents showed excellent activity against N. gonorrhoeae rega...

Induction of ampC β-lactamase expression can often compromise antibiotic treatment and is triggered by several β-lactams (such as cefoxitin and imipenem) and by the β-lactamase inhibitor clavulanic acid. The novel β-lactamase inhibitor avibactam (NXL104) is a potent inhibitor of both class A and class C enzymes. The potential of avibactam for induction of ampC expression in Enterobacter cloacae...

Penicillin-binding proteins (PBPs) are involved in the regulation of beta-lactamase expression by determining the level of anhydromuramylpeptides in the periplasmatic space. It was hypothesized that one or more PBPs act as a sensor in the beta-lactamase induction pathway. We have performed induction studies with Escherichia coli mutants lacking one to four PBPs with DD-carboxypeptidase activity...

One of the mechanisms Klebsiella pneumoniae and Escherichia coli resistance to ?-lactam antibiotics is production ?-lactamase enzymes. Among these are AmpC ?-lactamases, which confer a class antibiotics. However, little known about ?-lactamases K. E. clinical isolates in Qazvin, Iran. This study was designed assess ??lactamases-producing strains also identify prevalence ??lactamases genes. Anti...

BACKGROUND Staphylococci release a large number of enzymes. Some of these, such as coagulase, beta- lactamase, hemolysins and biofilms are considered indices of pathogenicity. OBJECTIVES The aim of the current study was based on the isolation and identification of Staphylococcus aureus and coagulase negative Staphylococci (CNS) strains from various skin lesions and examining their biofilms, b...