A comprehensive review of the natural history of Helicobacter pylori infection in children.

Helicobacter pylori infection is now recognised as a worldwide problem It is the most common cause of chronic gastritis, and is strongly linked to peptic ulcer disease and gastric cancer While the infection is usually acquired in childhood, there is typically a long period of latency with disease manifestations not appearing until adulthood Gastric cancer does not usually manifest until old age The infection has a high morbidity rate, but a low mortality rate and is curable with antibiotic therapy

Epidemiology of Helicobacter pylori infection

Helicobacter pylori can transform, in vivo as well as in vitro, from dividing spiral-shaped forms into nonculturable coccoids, with intermediate forms called U forms. The importance of nonculturable coccoid forms of H. pylori in disease transmission and antibiotic treatment failures is unclear. Metabolic activities of actively growing as well as nonculturable H. pylori were investigated by comparing the concentrations of cellular ATP and total RNA, gene expression, presence of cytoplasmic polyphosphate granules and iron inclusions, and cellular morphology during extended broth culture and nutritional cold starvation. In addition, the effect of exposing broth-cultured or cold-starved cells to a nutrient-rich or acidic environment on the metabolic activities was investigated. ATP was detectable up to 14 days and for at least 25 days after transformation from the spiral form to the coccoid form or U form in broth-cultured and cold-starved cells, respectively. mRNAs of VacA, a 26-kDa protein, and urease A were detected by using reverse transcription-PCR in cells cultured for 2 months in broth or cold starved for at least 28 months. The ATP concentration was not affected during exposure to fresh or acidified broth, while 4- to 12-h exposures of nonculturable cells to lysed human erythrocytes increased cellular ATP 12- to 150-fold. Incubation of nonculturable cold-starved cells with an erythrocyte lysate increased total RNA expression and ureA mRNA transcription as measured by quantitative real-time reverse transcription-PCR. Furthermore, the number of structurally intact starved coccoids containing polyphosphate granules increased almost fourfold (P = 0.0022) under the same conditions. In conclusion, a specific environmental stimulus can induce ATP, polyphosphate, and RNA metabolism in nonculturable H. pylori, indicating viability of such morphological forms.

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Effect of Cold Starvation, Acid Stress, and Nutrients on Metabolic Activity of Helicobacter pylori

Helicobacter pylori infection, iron absorption, and gastric acid secretion in Bangladeshi children

Antimicrobial susceptibility of 120 Helicobacter pylori isolates to metronidazole, tetracycline, clarithromycin, and amoxicillin was determined, and 77.5, 15, 10, and 6.6% of the isolates, respectively, were resistant. Only rdxA inactivation and both rdxA and frxA inactivation were responsible for metronidazole resistance in 66% (8 of 12) and 33% (4 of 12) of the isolates, respectively.

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Antimicrobial Susceptibility of Helicobacter pylori Strains Isolated in Bangladesh

The aim of this study was to determine the age-specific prevalence of Helicobacter pylori infection in infants and children aged 1-99 months from a poor periurban community in Bangladesh. We also examined the frequency of infection among infants and their 53 immediate family members and evaluated the relationship between infection and fasting serum group II pepsinogen (pepsinogen II) concentration in 76 children. Sixty-one percent of 1-3 month-old infants tested positive for H. pylori; this rate declined steadily to 33% in children aged 10-15 months and then increased to 84% in children aged 5-8 years. The H. pylori infection rate was 2.5 times higher in children with illiterate mothers. No difference in infection rate was detected among the family contacts of infected vs. noninfected infants. H. pylori-infected children had significantly higher serum pepsinogen II concentrations than did noninfected children (P < .001). We conclude that infection with H. pylori is highly prevalent and occurs at an early age. An environmental factor or factors, rather than or in addition to intrafamilial spread of this infection, are important in poor communities of Bangladesh. The higher levels of serum pepsinogen II in H. pylori-positive children might indicate the presence of gastritis in such asymptomatic children.

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Helicobacter pylori: Prevalence, Transmission, and Serum Pepsinogen II Concentrations in Children of a Poor Periurban Community in Bangladesh

Helicobacter pylori is an important cause of chronic gastritis and plays important roles in the etiology of peptic ulcer disease, gastric cancer and non-ulcer dyspepsia. While H. pylori infections occur worldwide, the great majority of information is from the developed countries, and little is known about the epidemiology of H. pylori in the developing countries, particularly in children.

D. Mahalanabis

Papers

Helicobacter pylori: Prevalence, Transmission, and Serum Pepsinogen II Concentrations in Children of a Poor Periurban Community in Bangladesh

Helicobacter pylori infection in infants and children of Bangladesh.