RESUMO
Helicobacter pylori has a chromosomal pathogenicity island (cagPAI), and the presence or absence of this Island places the microorganism into two types of strains: cagPAI+ which is associated to serious infectious processes, and cagPAI- related to mild to moderate infectious events. Simultaneous colonization by cagPAI+ and cagPAI- strains is frequent and these bacteria can interact among themselves. The aim of this project was to analyze the interaction between cagPAI+ and cagPAI- strains of H. pylori in experimental infection, using the Mongolian gerbil as an experimental animal model. We employed J99 (cagPAI+) and 251F (cagPAI-) strains, and obtained 3 derivate strains in successive isolation from experimentally infected gerbils. By RAPD-PCR we found that cagPAI+ and cagPAI- underwent genetic rearrangement during the gerbil-adaptation process. We identified individual isolates from gerbils, and by in situ hybridization we established that both type of strains were able to colonize the same regions of the host's stomach, and induce a mild to moderate inflammatory process. We studied the competence between cagPAI+ and cagPAI- strains by simultaneous and sequential infections. The study shows that in both colonization experiments, the cagPAI- strains were more efficient than cagPAI+ strains in colonizing the infected host by displacing cagPAI+.
Assuntos
Antígenos de Bactérias/biossíntese , Proteínas de Bactérias/biossíntese , Ilhas Genômicas , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/patologia , Helicobacter pylori/genética , Helicobacter pylori/patogenicidade , Fatores de Virulência/biossíntese , Animais , Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Técnicas de Tipagem Bacteriana , Análise por Conglomerados , Impressões Digitais de DNA , DNA Bacteriano/genética , Gerbillinae/microbiologia , Helicobacter pylori/classificação , Helicobacter pylori/isolamento & purificação , Masculino , Técnica de Amplificação ao Acaso de DNA Polimórfico , Recombinação Genética , Índice de Gravidade de Doença , Virulência , Fatores de Virulência/genéticaRESUMO
OBJECTIVE: To identify the prevalence of dental caries and to evaluate the risk cariogenic factors in adolescents of the State of Mexico. MATERIAL AND METHODS: An observational, descriptive and transversal study was conducted. The sample consisted of 109 teenagers, with ages ranging from 14 to 16 years old, 50 male and 59 female. Their teeth were evaluated using the DMFS index (decayed, lost and filled on the surface); the study was conducted by a WHO criteria standardized dentist researcher, with an intraexaminator Kappa value of 0.96. A survey was also conducted to establish the risk factors related to dental caries. RESULTS: The DMFS results found were of 4.05 +/- 3.47. In males the DMFS was of 3.50 +/- 3.56 with the following distribution: DS 3.22 +/- 3.54, MS 0.10 +/- 0.58 y FS 0.18 +/- 0.72, while with females the DMFS was of 4.51 +/- 3.35, DS 3.86 +/- 3.21, MS 0.15 +/- 0.61 and FS 0.51 +/- 1.19. Dental caries is related to the following variables: gender, frequency of toothbrushing, attendance to the dentist and intake of sugared products. CONCLUSIONS: It is recommended to continue with the health promotion programs, as well as with the use of fluoridated products, emphasizing tooth brushing and a decrease in the intake of sugared products.
