Quantitative Detection of <i>Helicobacter pylori</i> by Real Time PCR in Drinking Water—Environmental and Public Health Risk Significance

Abstract

Helicobacter pylori (H. pylori) is bacteria considered to be present in half of the population and it is a public health problem worldwide. Most patients infected with H. pylori show no clinical symptoms; nonetheless, approximately 10% to 20% of these patients will develop peptic ulcers and 1% will develop gastric cancer. The International Agency for Research on Cancer has classified H. pylori as a Group 1 carcinogen, recognized as the only bacteria capable of producing cancer. Samples of drinking water (n = 44) from aqueducts with chlorination treatment in selected areas with high prevalence of gastric cancer were analyzed in Costa Rica. Samples of drinking water from Panamá (n = 44) from aqueducts supplying untreated water for human consumption in the province of Chiriquí were also analyzed. The molecular marker of H. pylori, glmM, was used, and to optimize the Real Time PCR (qPCR) technique, annealing temperature, concentration of primers and probe were standardized; also, by analyzing different standard curves, the best reaction conditions that allowed detecting and quantifying the gene were determined. The LightCycler ® 480 II (LC480II) equipment from Roche Diagnostics GmbH was used, as well as the Absolute Quantification Analysis by means of the Second Derivative Maximum Method. In the case of the samples from Costa Rica, it was determined that 79.5% were positive for H. pylori; removing outlier high average, quantification of bacteria was determined in 3.6 × 10 3 copies/100 mL. For Panamá it was determined that 86% of the samples were found positive for the presence of H. pylori; removing outlier high V. Montero-Campos et al. 119average quantification of bacteria was determined at 3.3 × 10 2 copies/100 mL. The difference in values between the aqueducts in both countries revealed an environmental distribution of the bacteria of epidemiological interest in each case.

Reduction of Helicobacter pylori cells in rural water supply using slow sand filtration

“…Vesga et al ( 2018a ) also reports the H. pylori quantity at the outlet of the water treatment plants and after chlorination with concentration values that ranged between 5.77 and 2.12 × 10 3 GU/sample. Similarly, studies carried out in Panama, Costa Rica, Perú show concentrations in drinking water up to 3.6 × 10 3 UG/100 ml, even after disinfection (Boehnke et al, 2018 ; Montero Campos et al, 2015 ). These reported values show little to no pathogen reduction for the treatment evaluated and after disinfection.…”

Genetic diversity analysis of Piper betle from eight accessions of Indonesia based on SRAP markers

“…Separation of genomic DNA, or DNA fragments, was carried out essentially using a standard agarose-gel electrophoresis method (Montero-Campos et al 2015;Lee et al 2012). Genomic DNA was separated using 1% (w/v) agarose gel at 100 Volts for 30 min in 45 mM Tris-borate, 1 mM EDTA (TBE) running buffer.…”

Helicobacter pylori en Costa Rica, más de una década de investigaciones

“…Una observación importante a esta bacteria es que, a pesar de que puede ser transmitida por agua, es incapaz de crecer en cultivo líquido como cualquier otra bacteria, por esto es que sólo se pudo obtener cultivos positivos si la bacteria estaba adherida al papel de filtro; ya fue discutido anteriormente la imperiosa necesidad de crecer como biofilme. Otro proyecto ejecutado en el CIB [14], tuvo como objetivo cuantificar las copias de la bacteria en muestras de agua de Costa Rica y Panamá. Se trabajó con muestras de Costa Rica tratadas con cloro (n = 44) de áreas seleccionadas con alta prevalencia de cáncer gástrico, que correspondían a los cantones de: Central, Oreamuno y Paraíso de Cartago.…”

“…Panamá presenta proporcionalmente mucho menores tasas de cáncer gástrico que Costa Rica a la fecha del artículo original [14], que son 10 casos por 100.000 habitantes, contrastado con Costa Rica para la fecha de ese artículo con respecto a datos estadísticos disponibles de 2003 para hombres de 31.87 casos por 100,000 habitantes y 17.42 casos por 100,000 habitantes para mujeres en el mismo año (figura 3). En un trabajo presentado en el VI Simposio Internacional de Helicobacter pylori, San José, Costa Rica en el año 2014, llevada a cabo sobre Prevalencia de Helicobacter pylori en biopsias gástricas de pacientes dispépticos de zonas de alta y baja incidencia de cáncer gástrico en Costa Rica [16], se analizó 135 biopsias de pacientes dispépticos de los cantones de Abangares de Guanacaste y Paraíso de Cartago, como zonas de baja y alta incidencia respectivamente.…”