The chromogenic cephalosporin nitrocefin was used to detect the presence of beta-lactamase in cerebrospinal fluid of patients suffering from ampicillin-resistant Haemophilus influenzae meningitis. Five samples of spinal fluid containing ampicillin-resistant isolates were studied, and all had beta-lactamase activity. When samples of spinal fluid containing 33 ampicillin-sensitive isolates and 23...

Canadian invasive Haemophilus influenzae isolates from 1990 to 2006 were examined for antibiotic susceptibility: 42 strains (17.8%) were resistant to ampicillin by beta-lactamase production, 5.5% were beta-lactamase negative ampicillin intermediate, and 2.5% were intermediate to only the 2-microg ampicillin disk. An increase in beta-lactamase-negative ampicillin-intermediate strains has been fo...

The in vitro activities of two new beta-lactam antibiotics, cefotaxime and moxalactam (LY127935), were compared with those of cefamandole, cefoxitin, cefuroxime, and ampicillin against both beta-lactamase-producing and non-beta-lactamase-producing isolates of Haemophilus influenzae. Both cefotaxime and LY127935 were highly active against all isolates irrespective of beta-lactamase production.

Pseudomonas aeruginosa produces a low basal level of beta-lactamase (0.002 to 0.004 IU/mg of protein when benzylpenicillin is used as substrate). The beta-lactamase specific activity can be increased several hundredfold by growing the bacteria in the presence of beta-lactam antibiotics. This induction was studied in Pseudomonas aeruginosa 1822s. The single-cell resistance to benzylpenicillin wa...

Six strains of multidrug-resistant Stenotrophomonas maltophilia were isolated from cultured yellowtail. The strains were divided into two clusters based on the 16S rRNA genes, and all of them contained L1 metallo-beta-lactamase and L2 beta-lactamase genes. Differences in the intercluster divergence between the lactamase genes suggest that horizontal transfer of the genes occurred.

A novel (+)-γ-lactamase used for the resolution of racemic γ-lactam from Bradyrhizobium japonicum USDA 6 was found as a result of sequence-structure guided genome mining. It consists of 409 amino acids, only 49% of which are identical to the amino acid sequences of the known (+)-γ-lactamase from Sulfolobus solfataricus. This is only the third (+)-γ-lactamase gene to be reported.

BACKGROUND Co production of 16S rRNA methylases gene and β-Lactamase gene among Enterobacteriaceae isolates conferring resistance to both therapeutic options has serious implications for clinicians worldwide. METHODS To study co existence of 16S rRNA methylases (armA, rmtA, rmtB, rmtC, rmtD, and npmA) and β-Lactamase (blaTEM-1, blaSHV-12, blaCTX-M-14) genes, we screened all phenotypic positiv...

Eighty-three per cent of 200 different freshly isolated cultures of Staphylococcus epidermidis produced beta lactamase. Growth in the presence of acridine orange or ethidium bromide or growth at 44 C resulted in a high frequency of loss of the beta lactamase genes in some strains of S. epidermidis. The relationship between beta-lactamase production and resistance to mercuric, cadmium and arsena...

Randomly selected strains of beta-lactamase-negative and beta-lactamase-positive Neisseria gonorrhoeae were tested by an agar dilution method for susceptibility to rosamicin, josamycin, erythromycin, clindamycin, and penicillin G. Rosamicin was more active than erythromycin, which was more active than josamycin or clindamycin; the latter two were similar in their activity. The susceptibility to...

background :   imipenem-resistant gram negative bacteria, resulting from metallo-beta-lactamase (mbls)-producing strains have been reported to be among the important causes of nosocomial infections and of serious therapeutic problem worldwide. because of their broad range, potent carbapenemase activity and resistance to inhibitors, these enzymes can confer resistance to almost all beta-lactams....