RESUMO
Helicobacter pylori infection is mainly acquired in childhood, and polymorphisms in the host genes coding for Toll-like receptors (TLRs) may influence the innate and adaptive immune response to the infection, affecting the susceptibility to H. pylori or the disease outcomes. Our aim was to investigate whether TLR4, TLR2, and TLR5 polymorphisms were associated with H. pylori susceptibility and risk for duodenal ulcer in children. Gastric biopsy specimens were obtained at endoscopy for evaluation of H. pylori status, TLR4, TLR2 and TLR5 polymorphisms from 486 children (254 H. pylori-negative and 232 H. pylori-positive: 72 with and 160 without duodenal ulcer). cagA status of H. pylori infection was investigated by PCR. The levels of gastric cytokines were detected by ELISA. H. pylori-positivity or duodenal ulcer were not associated with TLR2, TLR4 or TLR5 polymorphisms. Otherwise, the presence of TLR4 polymorphic allele was associated with infection by cagA-positive strains and with increased gastric levels of interleukin-8 and interleukin-10. TLR4 polymorphism might ultimately contribute to more severe consequences of the infection in adulthood since it was associated with susceptibility to cagA-positive H. pylori infection early in life.
Assuntos
Úlcera Duodenal/genética , Úlcera Duodenal/microbiologia , Infecções por Helicobacter/complicações , Infecções por Helicobacter/genética , Helicobacter pylori/imunologia , Polimorfismo Genético , Receptores Toll-Like/genética , Adolescente , Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Criança , Pré-Escolar , Citocinas/análise , Suscetibilidade a Doenças , Úlcera Duodenal/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Mucosa Gástrica/química , Mucosa Gástrica/imunologia , Infecções por Helicobacter/imunologia , Humanos , Lactente , Masculino , Reação em Cadeia da Polimerase , Fatores de Risco , Fatores de Virulência/genéticaRESUMO
Helicobacter pylori resistance to metronidazole was detected in 107 (52.97%) of 202 strains. Twenty (9.85%) strains, 18 of them harboring 23S ribosomal DNA mutations, were resistant to clarithromycin. Metronidazole resistance was associated with female gender. Resistance to metronidazole and resistance to clarithromycin were associated. Increasing clarithromycin resistance rates were observed over time.
