Drug-resistant strains of the ulcer-causing bacterium Helicobacter pylori now occur in nearly half of Japanese children. But no such strains were found in their parents' stomachs, say researchers charting the rise of antibiotic resistance.
H. pylori causes stomach upset, ulcers and, in some cases, stomach cancer. It can usually be treated with antibiotics. Japan has one of the highest rates of H. pylori infection in the world - up to 70 per cent of those older than 65 years have the bacterium.
Ikue Taneike of the Niigata University School of Medicine and her colleagues studied eight families where both parents and children were infected with H. pylori. Taneike isolated DNA from the bacteria and identified the strains.
In one family, a boy and his parents were infected with the same strain. In another, a boy and his father shared one strain, while the other boy and his mother had a different strain. Taneike is confident the strains were passed on from the parents to the children.
However, while the parents' strains were all treatable with the antibiotic clarithromycin, 44 per cent of the children's strains were clarithromycin-resistant.
Taneike thinks that although the parent and child strains started out identically, those in the children have mutated, probably through overuse of clarithromycin in treating respiratory problems and chronic sinusitis.
During treatment, the H. pylori colonising the stomach can develop resistance, she says. This tendency to evolve resistance, says Taneike, will make future eradication of H. pylori extremely difficult.
The research was presented at the 40th Interscience Conference on Antimicrobial Agents and Chemotherapy in Toronto, Canada. For more stories from the conference visit www.newscientist.com/conferences/conflist.jsp?conf=ICAAC200009.
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