The main cause of failure of Helicobacter pylori eradication therapy is resistance to clarithromycin. The resistance is due to three point mutations in two positions on the 23S rRNA (A2142C, A2142G, and A2143G). Our aim was to develop a rapid and accurate method to detect these mutations directly on biopsy specimens. We developed a real-time PCR that included a simultaneous detection of the amplicons by hybridization of two probes labeled with LC-Red and fluorescein by using the fluorescence resonance energy transfer (FRET) technology and melting curve analysis with the LightCycler thermocycler. The assay was first applied successfully on reference strains, reference plasmids, and H. pylori-negative biopsies. Biopsies from 200 patients having failed a first eradication attempt and for whom the H. pylori strain was available were then tested with the new assay. A result was obtained in 199 cases; a single genotype was detected in 157 cases, two genotypes were detected in 41 cases, and three genotypes were detected in one case. There were, in total, seven discrepancies between the real-time PCR and the phenotypic method of determination of clarithromycin susceptibility, and in an additional four cases the two phenotypic methods were in disagreement. PCR-restriction fragment length polymorphism was applied to a sampling of biopsies, including all of the cases with multiple genotypes and all the cases with discrepant results. Finally, in four cases with discrepant results, the real-time PCR detected the resistant population at a concentration so low that it could not be detected by the phenotypic method, while in three cases other mutations could be involved. This assay had an accuracy at least as satisfactory as that of the phenotypic tests and could be performed within 2 h, allowing it to be used before the administration of therapy in the case of a first H. pylori eradication.

SummaryTwo full-genome sequences of porcine circovirus type 3 (PCV3) are reported. The genomes were recovered from pooled serum samples from sows who had just deliv-

SummaryWe evaluated the role of the family in the transmission of Helicobacter pylori infection in preschool-aged children from a rural district in the State of Minas Gerais, Brazil. Sixty-six families (66 index children, 63 mothers, 60 fathers and 134 siblings), defined as at least one parent living in the same household with at least one offspring up to 8 years old, were studied. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression controlling for age, gender, number of children in household and H. pylori status of the father, mother and siblings. The prevalence of the infection was 69.7% (469 of 673) and it increased with age (P < 0.001). Positive mothers were a strong and independent risk factor for infection (OR 22.70;). Positive siblings were also positively associated with infection (OR 1.81; 95% CI 1.01-3.30).

Although infection with a cagA-positive Helicobacter pylori strain is considered a risk factor for the development of duodenal peptic ulcer in adults, this association has not been demonstrated in children. The presence of cagA was investigated by polymerase chain reaction in H. pylori strains isolated from 27 children with duodenal ulcer and 53 without duodenal ulcer. All patients (100%) with duodenal ulcer and 33 (62.3%) without ulcer were colonized by a cagA-positive strain (P=.00007). A cagA-positive status was also associated with a more marked macroscopic gastritis, with a greater inflammatory infiltrate of both mononuclear and polymorphonuclear cells in the antral and oxyntic gastric mucosae and degenerative and regenerative changes of the gastric mucosa. Increased cagA positivity was also associated with increased age, but no association between cagA-positive status and sex was observed.

The babA2 and cagA genes were investigated in 208 Brazilian Helicobacter pylori strains. A strong association between babA2 and duodenal ulcer or gastric carcinoma was observed, even after adjusting for confounding factors, such as age, gender, and cagA status. cagA-positive strains were also independently associated with H. pylori-related diseases.Helicobacter pylori infection is one of the most common chronic bacterial infections worldwide. Although most infected persons remain asymptomatic, 15 to 20% of H. pylori-positive individuals will develop a peptic ulcer, gastric carcinoma, or mucosa-associated lymphoid tissue lymphoma (19). However, it remains unclear why only a minority of infected patients develop the severe associated diseases. This phenomenon may be due to differences in host genetics, environmental factors, and the virulence of bacterial strains.There is now evidence for the existence of different strains of H. pylori with different degrees of virulence (2,3,18). The cytotoxin-associated gene cagA was the first gene found to be differentially present in H. pylori isolates and is considered a marker for the presence of the cag pathogenicity island (4). In addition to other putative virulence properties encoded by the cag pathogenicity island, several genes of the island encode proteins, such as interleukin-8, that enhance the gastric inflammatory response to the infection.A cagA-positive status has been associated with severe clinical outcomes in some Western countries (3,14,18). Conversely, since the majority of H. pylori-infected individuals in Asian countries harbor cagA-positive strains, associations of cagA status and diseases are not observed in Asia (11,20). The recently described blood group antigen-binding adhesin BabA has been shown to mediate adherence of H. pylori to Lewis b (␣-1,3/4-difucosylated) receptors on gastric epithelium (8). Although three bab alleles have been identified (babA1, babA2, and babB), only the babA2 gene product is necessary for Lewis b binding activity (8,16). Studies in Western countries have demonstrated associations between babA2-positive status and duodenal ulcer as well as gastric carcinoma (7). However, in Asian countries, most of the circulating H. pylori strains are babA2 positive, whether or not they were isolated from asymptomatic or diseased patients (9,10,12,20). In addition to these differences between Western and Eastern countries, the prevalence of babA2-positive H. pylori strains also seems to vary among the Western populations, being much lower in patients from Portugal (13) than in those from Germany, the United States, or Colombia (7, 20). Since there are few studies on this subject, specifically evaluating patients with gastric carcinoma, the frequency of babA2 H. pylori strains may vary around the world and because the clinical relevance of babA2-positive strains has not been determined in Brazil, we investigated associations between babA2 and cagA genotypes and different H. pylori infection outcomes, adjusting for confounding factors.H Two ...