A previous study suggested that Helicobacter pylori strains possessing dupA are positively associated with duodenal ulceration and negatively associated with gastric adenocarcinoma. We determined the prevalence of dupA in H. pylori strains recovered from 4 independent populations and found a significant association with gastric cancer but not with duodenal ulceration.Helicobacter pylori infects approximately one-half of the world's population and is a major cause of peptic ulceration and gastric adenocarcinoma. Among infected persons, who develops disease depends on the bacterial strain's virulence, the host's genetic susceptibility, and environmental factors. H. pylori virulence factors associated with the development of ulceration and gastric cancer include VacA, CagA, BabA, and OipA [1][2][3][4][5][6]. Recently the gene dupA was identified in H. pylori strains isolated from patients in Colombia, South Korea, and Japan; infection with dupA-positive strains was significantly associated with duodenal ulceration but negatively associated with gastric cancer [7]. The mechanism appeared to involve induction of IL-8 secretion in gastric epithelial cells followed by increasing gastric inflammation [7]. Thus, dupA appeared to act like other proinflammatory virulence factors, including the cag pathogenicity island and, more controversially, oipA [5,6,8,9].

The Helicobacter pylori virulence gene, cagA, and active forms of the vacuolating cytotoxin gene, vacA, are major determinants of pathogenesis. However, previous studies linking these factors to disease risk have often included patients using aspirin/nonsteroidal anti-inflammatory agents (NSAIDs) or acid-suppressing drugs, both of which may confound results. Also, particularly for gastric cancer (GC), controls have often been of quite different ages. Here, we performed a careful study in a "clean" Belgian population with gastric cancer cases age and sex matched to 4 controls and with a parallel duodenal ulcer (DU) group. As in other populations, there was a close association between the presence of cagA and the vacA s1 genotype. For GC, associations were found for vacA s1-positive (P ‫؍‬ 0.01, odds ratio [OR], 9.37; 95% confidence interval [CI], 1.16 to 201.89), i1-positive (P ‫؍‬ 0.003; OR, 12.08; 95% CI, 1.50 to 259.64), and cagA-positive status (P < 0.05; OR, infinity; 95% CI, 0.76 to infinity). For DU, associations were found with vacA s1 (P ‫؍‬ 0.002; OR, 6.04; 95% CI, 1.52 to 27.87) and i1 (P ‫؍‬ 0.004; OR, 4.35; 95% CI, 1.36 to 14.78) status but not with cagA status. Neither condition showed independent associations with the vacA m1 allele or with more biologically active forms of cagA with longer 3= variable regions. In this Belgian population, the best markers of gastric cancer-and duodenal ulcer-associated strains are the vacA s1 and i1 genotypes. This fits with experimental data showing that the s and i regions are the key determinants of vacuolating cytotoxin activity.

BackgroundGroup A Streptococcus (GAS) clinical and molecular epidemiology varies with location and time. These differences are not or are poorly understood.Methods and FindingsWe prospectively studied the epidemiology of GAS infections among children in outpatient hospital clinics in Brussels (Belgium) and Brasília (Brazil). Clinical questionnaires were filled out and microbiological sampling was performed. GAS isolates were emm-typed according to the Center for Disease Control protocol. emm pattern was predicted for each isolate. 334 GAS isolates were recovered from 706 children. Skin infections were frequent in Brasília (48% of the GAS infections), whereas pharyngitis were predominant (88%) in Brussels. The mean age of children with GAS pharyngitis in Brussels was lower than in Brasília (65/92 months, p<0.001). emm-typing revealed striking differences between Brazilian and Belgian GAS isolates. While 20 distinct emm-types were identified among 200 Belgian isolates, 48 were found among 128 Brazilian isolates. Belgian isolates belong mainly to emm pattern A–C (55%) and E (42.5%) while emm pattern E (51.5%) and D (36%) were predominant in Brasília. In Brasília, emm pattern D isolates were recovered from 18.5% of the pharyngitis, although this emm pattern is supposed to have a skin tropism. By contrast, A–C pattern isolates were unfrequently recovered in a region where rheumatic fever is still highly prevalent.ConclusionsEpidemiologic features of GAS from a pediatric population were very different in an industrialised country and a low incomes region, not only in term of clinical presentation, but also in terms of genetic diversity and distribution of emm patterns. These differences should be taken into account for designing treatment guidelines and vaccine strategies.

We analyzed the rates of antimicrobial resistance of Helicobacter pylori strains isolated from patients from 1990 to 2009 and identified risk factors associated with resistance. Gastric biopsy specimens were collected from several digestive disease centers in Brussels, Belgium. We routinely performed antimicrobial susceptibility testing for clarithromycin (CLR), metronidazole, amoxicillin, tetracycline, and ciprofloxacin. Evaluable susceptibility testing was obtained for 9,430 strains isolated from patients who were not previously treated for Helicobacter pylori infection (1,527 isolates from children and 7,903 from adults) and 1,371 strains from patients who were previously treated (162 isolates from children and 1,209 from adults). No resistance to amoxicillin was observed, and tetracycline resistance was very rare (<0.01%). Primary metronidazole resistance remained stable over the years, with significantly lower rates for isolates from children (23.4%) than for isolates from adults (30.6%). Ciprofloxacin resistance remained rare in children, while it increased significantly over the last years in adults. Primary clarithromycin resistance increased significantly, reaching peaks in 2000 for children (16.9%) and in 2003 for adults (23.7%). A subsequent decrease of resistance rates down to 10% in both groups corresponded to a parallel decrease in macrolide consumption during the same period. Multivariate logistic regression revealed that female gender, age of the patient of 40 to 64 years, ethnic background, the number of previously unsuccessful eradication attempts, and the different time periods studied were independent risk factors of resistance to clarithromycin, metronidazole, and ciprofloxacin. Our study highlights the need to update local epidemiological data. Thus, the empirical CLR-based triple therapy proposed by the Maastricht III consensus report remains currently applicable to our population.

The prevalence of Helicobacter pylori infection is decreasing in developed countries. In this study we included 22,612 patients in whom a first culture of gastric biopsy (routinely performed in our medical centres) yielded an interpretable result over a 20-year period (1988-2007) in Brussels. The effects of patients' age, gender and ethnic background were analysed. The overall proportion of H. pylori-infected patients was 37·7%, with a progressive decline over time (P<10(-5)). A gender effect was observed in adults. The lowest infection rate was observed in Western European patients (n=11,238) with respectively 36·2% and 15·2% infected subjects in 1988 and 2007, compared to 71·7% and 40% in North African patients (n=3200) (P<10(-5)). However, no trend of decline was observed over time in North African children aged ≤9 years. These data show the effects of time, age and ethnicity on the prevalence of H. pylori infection, and its complex heterogeneity in the same cosmopolitan urban area.

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