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.