The source of Campylobacter pylori

Prevalence of Helicobacter pylori infection in two Spanish regions with different incidence of gastric cancer

It is a cross-sectional study, comparing the prevalence of Helicobacter pylori infection (prevalence of IgG antibodies to H. pylori) in the healthy population of Ubrique and Grazalema (mountain location, mortality from stomach cancer 20/100,000) and in Barbate, (coastal location, mortality from stomach cancer 10/100,000) in the province of Cadiz, southern Spain. The subjects were randomly selected, 163 men and 169 women, 18 years or older; 179 persons were studied in the inland, and 154 in the littoral in January 1997. Of the 332 subjects investigated, 43% were positive, a mean antibody titer of 337 IU/1 (95 % CI: 254-420), and 56% were negative, with a mean titer of 18 IU/1 (95% CI: 15-19). In the coastal population, 30% has positive titers and 54% in the mountain location. By age: 18-40 years, 30% of littoral and 41% of inland population had positive titers; 41-60 years, 35% of those living in the littoral and 58% of inland population had positive titers; > 60 years, 24% of coastal inhabitants and 62% of those living in the inland had positive titers. Living in mountain locations in the province of Cadiz involves a greater ecological risk for H. pylori infection (p < 0.05).

Adhesion of Helicobacter pylori and Escherichia coli to human and bovine surface mucus cells in vitro

Helicobacter pylori shows in vivo a specific affinity for epithelial surface mucus cells (SMC) of the human stomach. We studied the in vitro adhesion of five different H. pylori strains and one non-pathogenic Escherichia coli-strain to (a) human antral SMC, obtained during gastroscopy; (b) human tumour SMC, from a carcinoma cell line (CRL 1739 AGS); and (c) bovine SMC, obtained from the abomasum. SMC of different origin were characterized by means of electron microscopy and immunohistochemistry, and showed similar main features: all cells showed intra-cellular structures like zymogens and PAS-positive mucin granules. HSMC were antibody-positive against epithelial cell markers. All five H. pylori strains adhered to human SMC (HSMC) and tumour SMC (TSMC). Only one strain additionally adhered to bovine SMC (BSMC). No adhesion to any of these cells was observed with E. coli. Adhesion in vitro is characterized by a close membrane-to-membrane association between H. pylori and the target cells. This phenomenon suggests a specific receptor-ligand interaction.

Isolation of Helicobacter strains from wild bird and swine feces

We report the first isolations of Helicobacter strains from wild birds and swine. Genus-specific oligonucleotide probes identified nine Cape Cod isolates from gull, tern, house sparrow, and pig feces as Helicobacter spp. and not Campylobacter spp. Antibiotic sensitivity and urease tests distinguished three phenotypes. Strains examined rapidly lost culturability under simulated natural conditions.

Use of autoradiography to assess viability of Helicobacter pylori in water

Autoradiographic methods have been developed to detect metabolic activity of viable but nonculturable cells of Helicobacter pylori in water. Four strains of H. pylori were studied by using microcosms containing suspensions of 72-h cultures in water. The suspensions of aged, nonculturable cells of H. pylori were incubated with [3H]thymidine for 24 to 72 h, after which the cell suspensions were exposed to Kodak NTB2 emulsion for 3 to 28 days. Each sample was processed with three separate controls to rule out false-positive reactions. The organism remains viable and culturable under these conditions for up to 48 h and, in some cases, 20 to 30 days, depending on physical conditions of the environment. We found that temperature was a significant (P < or equal to 0.01) environmental factor associated with the viability of H. pylori cells in water. Autoradiographs of tritium-labeled cells of H. pylori revealed aggregations of silver grains associated with uptake by H. pylori of radiolabelled substrate. Findings based on the autoradiographic approach give strong evidence supporting the hypothesis that there is a waterborne route of infection for H. pylori. The possibility that H. pylori may persist in water in a metabolically active stage but not actively growing and dividing is intriguing and relevant to public health concerns.