RESUMO
BACKGROUND: Helicobacter pylori (H. pylori) is one of the most common bacterial infections in humans and this infection can lead to gastric ulcers and gastric cancer. H. pylori is one of the most genetically variable human pathogens and the ability of the bacterium to bind to the host epithelium as well as the presence of different virulence factors and genetic variants within these genes have been associated with disease severity. Nicaragua has particularly high gastric cancer incidence and we therefore studied Nicaraguan clinical H. pylori isolates for factors that could contribute to cancer risk. METHODS: The complete genomes of fifty-two Nicaraguan H. pylori isolates were sequenced and assembled de novo, and phylogenetic and virulence factor analyses were performed. RESULTS: The Nicaraguan isolates showed phylogenetic relationship with West African isolates in whole-genome sequence comparisons and with Western and urban South- and Central American isolates using MLSA (Multi-locus sequence analysis). A majority, 77 % of the isolates carried the cancer-associated virulence gene cagA and also the s1/i1/m1 vacuolating cytotoxin, vacA allele combination, which is linked to increased severity of disease. Specifically, we also found that Nicaraguan isolates have a blood group-binding adhesin (BabA) variant highly similar to previously reported BabA sequences from Latin America, including from isolates belonging to other phylogenetic groups. These BabA sequences were found to be under positive selection at several amino acid positions that differed from the global collection of isolates. CONCLUSION: The discovery of a Latin American BabA variant, independent of overall phylogenetic background, suggests hitherto unknown host or environmental factors within the Latin American population giving H. pylori isolates carrying this adhesin variant a selective advantage, which could affect pathogenesis and risk for sequelae through specific adherence properties.
Assuntos
Adesinas Bacterianas/genética , Helicobacter pylori/classificação , Helicobacter pylori/genética , Adesinas Bacterianas/química , Adolescente , Adulto , Idoso , Sequência de Aminoácidos , Antígenos de Bactérias/genética , Feminino , Variação Genética , Genoma Bacteriano , Infecções por Helicobacter/microbiologia , Helicobacter pylori/patogenicidade , Humanos , Pessoa de Meia-Idade , Dados de Sequência Molecular , Tipagem de Sequências Multilocus , Nicarágua , Filogenia , Fatores de Virulência/química , Fatores de Virulência/genética , Adulto JovemRESUMO
OBJECTIVE: To examine healthcare utilization according to family income in children with inflammatory bowel disease (IBD). STUDY DESIGN: A population-based cohort of children aged <18 years diagnosed with IBD between 1994 and 2004 was followed using health administrative data. Multivariate models were used to test the association between mean neighborhood income quintile and physician and emergency department visits, hospitalizations, or surgeries. RESULTS: Compared with children from higher-income neighborhoods, children from low-income neighborhoods were more likely to be hospitalized at least once (hazard ratio, 1.17; 95% CI, 1.05 to 1.30) or to visit the emergency department (hazard ratio, 1.21; 95% CI, 1.09 to 1.35), and had more IBD-related physician visits (OR, 3.73; 95% CI, 1.05 to 13.27). Children from low-income neighborhoods with Crohn's disease (but not those with ulcerative colitis) were more likely to undergo intra-abdominal surgery within 3 years of diagnosis (OR, 1.22; 95% CI, 1.01 to 1.49), especially when diagnosed after 2000 (OR, 1.79; 95% CI, 1.27 to 2.53). CONCLUSIONS: Lower income was associated with a higher rate of health services utilization in children with IBD and with a greater risk of surgery in children with Crohn's disease.