Non-diarrheagenic and diarrheagenic E. coli carrying supplementary virulence genes (SVG) are associated with diarrhea in children from Mexico.

Escherichia coli strains, including diarrheagenic E. coli (DEC), are among the most important causes of childhood diarrhea in developing countries. Since these strains also colonize healthy children, additional factors leading to diarrhea remains to be discovered. We therefore conducted a comprehensive study to investigate if supplementary virulence genes (SVG) carried by DEC strains and non-DEC strains, contribute to diarrhea in Mexican children. E. coli strains were isolated from n = 317 children between 6 and 12 years, n = 114 with diarrhea and n = 203 asymptomatic children from Northwestern Mexico, PCR was used to identify SVG, then virulence score and cytotoxic assay in HT-29 cells were performed to evaluate virulence of E. coli strains. DEC prevalence was 18.6% and its presence was significantly associated with diarrhea cases. aEPEC, tEAEC, ETEC, DAEC, aEAEC, tEPEC, and EIEC pathotypes were identified. aEPEC strains were significantly associated with asymptomatic children, whereas ETEC was only identified in children with diarrhea. E. coli strains carrying colonization-related SVG and/or proteolysis-related SVG were significantly associated with diarrhea. DEC strains were associated to diarrhea if strains carried SVG ehaC, kps, nleB, and/or espC. Virulence score was significantly higher in E. coli from diarrhea cases than asymptomatic. In addition, DEC strains carrying SVG+ were more virulent, followed by non-DEC SVG+ strains, and correlated with the cytotoxicity assay. Nearly 50% of DEC strains were MDR, and ~10% were XDR. In conclusion the findings of this work provide evidence that the presence of E. coli strains (regardless if strains are DEC or non-DEC) with SVG were associated with diarrhea in Mexican children.

Recurrencia de infección y diversidad de cepas de Helicobacter pylori en adultos tratados con terapia triple estándar empírica en una población de México / Recurrence of infection and diversity of Helicobacter pylori strains in an adult population in Mexico treated with empirical standard triple therapy

Introducción: posterior al tratamiento erradicador de Helicobacter pylori (H. pylori), podría presentarse recurrencia de infección debido a recrudescencia o reinfección. El objetivo de este estudio fue determinar la recurrencia de infección por H. pylori e identificar cepas virulentas de H. pylori al año posterior de su erradicación con terapia triple estándar. Material y métodos: se realizó un estudio cuasiexperimental. La población estudiada fueron pacientes con enfermedades digestivas asociadas a H. pylori que recibieron terapia triple estándar. Todos los pacientes antes del tratamiento erradicador, y solo aquellos pacientes con prueba de aliento con carbono 14 positivo un año posterior al tratamiento se les realizaron cultivos y reacción en cadena de la polimerasa (PCR) de biopsias gástricas para identificación de cepas. Se realizó análisis estadístico mediante el test t de Student y prueba exacta de Fisher, con un nivel de significancia de 0,05. Resultados: se revisaron 128 pacientes, 51 (39,8%) hombres y 77 (60,2%) mujeres, con una edad promedio de 54,8 (DE 13,8) años. Se halló recurrencia anual de infección por H. pylori en 12 (9,3%) pacientes y reinfección y recrudescencia anual en nueve (7%) y tres (2,3%) pacientes respectivamente. La tasa de recrudescencia en proteína antigénica (cagA) fue de 1/30 (3,3%) pacientes y en citotoxina vacuolizante (vacA) fue de 2/112 (1,8%) pacientes. La tasa de reinfección en cagA fue 3/30 (10%) pacientes y en vacA 6/112 (5,3%) pacientes. Conclusiones: en este estudio la recurrencia de infección fue mayor que en países desarrollados con baja prevalencia de H. pylori y menor que en países en vías de desarrollo con mayor prevalencia de H. pylori. Las cepas cagA o vacA s2/m2 fueron aisladas en reinfección y recrudescencia (AU)

Background. After eradication treatment for Helicobacter pylori, infection could recur due to recrudescence or re-infection. The objective of this study was to determine the recurrence of Helicobacter pylori infection and identify virulent Helicobacter pylori strains one year after eradication with standard triple therapy. Material and methods. A quasi-experimental study was performed that included a patient population with digestive diseases associated with Helicobacter pylori who had received standard triple therapy. Cultures and Polymerase Chain Reaction was performed on gastric biopsies for strain identification in all patients prior to eradication treatment and those with a positive carbon 14 breath test one year after eradication treatment. Statistical analysis was performed using the student T test and Fisher’s exact test, statistical significance was set at 0.05. Results. 128 patients were studied, 51 (39.8%) were male and 77 (60.2%) were female with an average age of 54.8 years (DE 13.8). There was an annual recurrence of Helicobacter pylori infection in 12 (9.3%) patients. An annual re-infection and recrudescence occurred in 9 (7 %) and 3 (2.3%) patients respectively. The recrudescence rate for cagA was 1/30 (3.3%) patients and 2/112 (1.8%) patients for vacA. The re-infection rate for cagA was 3/30 (10%) patients and 6/112 (5.3%) patients for vacA. Conclusions. The recurrence of infection in this study was higher than that recorded in developed countries with a low prevalence of H. pylori and lower than that recorded in developing countries with a higher prevalence of H. pylori. The cagA or vacA s2/m2 strains were isolated after re-infection and recrudescence (AU)

Recurrence of infection and diversity of Helicobacter pylori strains in an adult population in Mexico treated with empirical standard triple therapy.

BACKGROUND: After eradication treatment for Helicobacter pylori, infection could recur due to recrudescence or re-infection. The objective of this study was to determine the recurrence of Helicobacter pylori infection and identify virulent Helicobacter pylori strains one year after eradication with standard triple therapy. MATERIAL AND METHODS: A quasi-experimental study was performed that included a patient population with digestive diseases associated with Helicobacter pylori who had received standard triple therapy. Cultures and Polymerase Chain Reaction was performed on gastric biopsies for strain identification in all patients prior to eradication treatment and those with a positive carbon 14 breath test one year after eradication treatment. Statistical analysis was performed using the student T test and Fisher's exact test, statistical significance was set at 0.05. RESULTS: 128 patients were studied, 51 (39.8%) were male and 77 (60.2%) were female with an average age of 54.8 years (DE 13.8). There was an annual recurrence of Helicobacter pylori infection in 12 (9.3%) patients. An annual re-infection and recrudescence occurred in 9 (7 %) and 3 (2.3%) patients respectively. The recrudescence rate for cagA was 1/30 (3.3%) patients and 2/112 (1.8%) patients for vacA. The re-infection rate for cagA was 3/30 (10%) patients and 6/112 (5.3%) patients for vacA. CONCLUSIONS: The recurrence of infection in this study was higher than that recorded in developed countries with a low prevalence of H. pylori and lower than that recorded in developing countries with a higher prevalence of H. pylori. The cagA or vacA s2/m2 strains were isolated after re-infection and recrudescence.