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...

beta-Lactamases are the main cause of bacterial resistance to penicillins and cephalosporins. Class A beta-lactamases, the largest group of beta-lactamases, have been found in many bacterial strains, including mycobacteria, for which no beta-lactamase structure has been previously reported. The crystal structure of the class A beta-lactamase from Mycobacterium fortuitum (MFO) has been solved at...

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...

A chromosomally encoded class D beta-lactamase, OXA-114, was characterized from Achromobacter xylosoxidans strain CIP69598. beta-Lactamase OXA-114 shared 56% amino acid identity with the naturally occurring class D beta-lactamase of Burkholderia cenocepacia and 42% identity with the acquired oxacillinases OXA-9 and OXA-18. OXA-114 has a narrow-spectrum hydrolysis profile, although it includes i...

Two hundred twenty-four isolates of Bacteroides sp. were recovered from recurrently inflamed tonsils, infected peritoneal fluid, abscesses, wounds, and burns of hospitalized children. Isolates were examined for beta-lactamase production by the chromogenic cephalosporin analog 87/312 methodology. Altogether, 119 isolates were beta-lactamase producers. Of these, 53 were in the B. fragilis group, ...

lactamase production. Reacteroides melaniongenicus, 14

The interactions between imipenem and four monobactams and three class A beta-lactamases have been studied in detail. Despite their reputation as being beta-lactamase-stable, some of these compounds were significantly hydrolysed by the enzymes. The results obtained with the Streptomyces albus G beta-lactamase have been analysed in the light of molecular modelling studies. The discussion is exte...

High Incidence of MDR and XDR Pseudomonas aeruginosa Isolates Harboring blaGES, blaVEB, blaPER Extended-Spectrum Beta-Lactamase Genes in Iran

Enterobacter aerogenes clinical isolate LOR was resistant to penicillins and ceftazidime but susceptible to cefuroxime, cephalothin, cefoxitin, cefotaxime, ceftriaxone, and cefepime. PCR and cloning experiments from this strain identified a novel TEM-type beta-lactamase (TEM-121) differing by five amino acid substitutions from beta-lactamase TEM-2 (Glu104Lys, Arg164Ser, Ala237Thr, Glu240Lys, an...

A simple colorimetric beta-lactamase assay for quantifying Leishmania amastigotes in macrophages grown in microtiter plates has been reported. The beta-lactamase gene was integrated into the rRNA region of the genome, thereby allowing for high-level stable expression of the enzyme. Both visceral leishmaniasis (VL) and post-kala azar dermal leishmaniasis (PKDL) isolates were transfected with bet...