High prevalence of virulent Helicobacter pylori strains in symptomatic Bulgarian patients.

The aim of the study was to evaluate the prevalence of main virulence genes in Helicobacter pylori strains from 116 patients with peptic ulcers (41 cases) and nonulcer diseases (75) by polymerase chain reaction (PCR) with pure cultures and to compare the results with those by multiplex PCR in 39 H. pylori-positive gastric biopsies in another center in Sofia, Bulgaria. Strain susceptibility to amoxicillin, metronidazole, and clarithromycin was determined by agar dilution method.

Synthesis and preliminary antimicrobial evaluation of new 7-(N-pyrrolyl) derivatives of cephalosporins.

A series of seven new cephalosporins was prepared for preliminary microbiological evaluation by N-acylation of 7-aminocephalosporanic acid with substituted N-pyrrolylcarboxylic acids via mixed anhydrides. The chemical structure of the compounds were confirmed by IR, 1H-NMR and mass spectral data. The 7-(N-pyrrolyl) cephalosporin derivatives were tested in vitro by the disc diffusion method upon 3 strains and subsequent determination of the minimal inhibitory concentration (MIC) of the most active ones upon 29 strains.