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A clinical trial was conducted in Argentina to determine the efficacy of clarithromycin plus lansoprazole for the treatment of Helicobacter pylori in duodenal ulcers and non-ulcer dyspepsia. PCR-RFLP was conducted on an 820-bp amplified product of the ureC gene of H. pylori to determine the genetic heterogeneity of 83 pretreatment and 21 post-treatment isolates. Twelve different restriction patterns were observed when digested with Sau 3A or Hha I, resulting in 40 different RFLP types. Comparison of isolates before treatment to after treatment showed that 20 of 20 patients had the same RFLP type. In addition, the presence of the cytotoxin-associated gene (cagA) and the vacuolating gene (vacA) were determined. All pretreatment isolates were positive for vacA whereas 75% of the pretreatment isolates were positive for cagA. The results of this study indicate that a high degree of heterogeneity exists among H. pylori and that infection is not limited to a small number of RFLP types.

Tigemonam and temocillin, but not aztreonam, bound to penicillin-binding proteins (PBPs) 1a and 3 of Escherichia coli with apparent improved affinity when challenged with benzylpenicillin at lowered temperatures. Half times for deacylation of the tigemonam-PBP complexes were shorter than were those of the corresponding aztreonam-PBP complexes. The implications of the routine testing of PBP affinities are discussed.

A multi-country clinical trial was conducted in ten European countries to determine the efficacy of clarithromycin-omeprazole dual therapy for treating Helicobacter pylori infection in peptic ulcers. Gastric biopsies were cultured for H. pylori before and after treatment. PCR-RFLP was used to determine the genetic heterogeneity of 100 H. pylori isolates from pretreatment and posttreatment biopsies. An 820 bp amplified fragment of the ureC gene was digested with the restriction enzymes Sau3A and Hhal. Fourteen different Sau3A patterns and 15 different Hhal patterns were identified among the pretreatment isolates. In combination, 42 different RFLP types were identified. Comparison of isolates before treatment with those after treatment showed that five of ten patients on clarithromycin-omeprazole dual therapy had the same RFLP type and that all 12 patients on omeprazole therapy alone had the same RFLP type. All isolates were susceptible to clarithromycin prior to treatment, while seven of ten patients on clarithromycin-omeprazole therapy had H. pylori that was resistant to clarithromycin after therapy and 11 of 12 patients on omeprazole therapy had isolates susceptible to clarithromycin after treatment. In addition to PCR-RFLP typing, the presence of the cytotoxin-associated gene (cagA) and the vacuolating gene (vacA) was determined; 79% of the isolates were cagA-positive and all were vacA-positive. The results of this study indicate that infection of H. pylori in Europe is not restricted to a few RFLP types. [ABSTRACT FROM AUTHOR]