Helicobacter pylori virulence genotypes in Bogotá River and wastewater treatment plants in Colombia.

BACKGROUND: Helicobacter pylori is a bacterium that infects 70%-80% of the population in Colombia, causing chronic gastritis in all those infected and gastric cancer in 1%-2% of those infected. In Colombia, some studies have identified the presence of vacA and cagA genes in environmental samples such as treated, surface, and wastewater, but they have not been evaluated in the Bogotá River. For this, the aim of this study was to identify the virulence genotypes of H. pylori present in samples from the Bogotá River and domestic wastewater treatment plants (WWTPs). MATERIALS AND METHODS: A total of 75 water samples (51 from the Bogotá River and 24 from wastewater treatment plants) were collected. The presence of H. pylori DNA and its virulence genotypes was determined by polymerase chain reaction (PCR). RESULTS: The presence of H. pylori DNA was demonstrated in 44% (33/75) of the samples, obtaining 63.6% (21/33) from the Bogotá River and 36.4% (12/33) from the WWTPs. The most prevalent H. pylori genotype was cagA (-) and vacAm1/s1/i1 being the most virulent of the vacA gene. CONCLUSIONS: This is the first study in Colombia that determines the cagA and vacA genotypes in surface water and WWTPs, indicating the circulation of virulent genotypes in the population. The presence of this pathogen in the waters can be represent a risk to the health of the surrounding population since these waters are reused by the communities for different purposes.

Bacteriophages of Helicobacter pylori.

The bacterium Helicobacter pylori colonize the stomach in approximately half of the world's population. Infection with this bacterium is associated with gastritis, peptic ulcer, adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Besides being a pathogen with worldwide prevalence, H. pylori show increasingly high antibiotic resistance rates, making the development of new therapeutic strategies against this bacterium challenging. Furthermore, H. pylori is a genetically diverse bacterium, which may be influenced by the presence of mobile genomic elements, including prophages. In this review, we analyze these issues and summarize various reports and findings related to phages and H. pylori, discussing the relationship between the presence of these elements and the genomic diversity, virulence, and fitness of this bacterium. We also analyze the state of the knowledge on the potential utility of bacteriophages as a therapeutic strategy for H. pylori.

Helicobacter pylori: Multiple resistance in patients from Bogotá, Colombia / Helicobacter pylori: resistencia múltiple en pacientes de Bogotá, Colombia

Introduction: The main cause for Helicobacter pylori infection treatment failure is antibiotic resistance, where clarithromycin and metronidazole play the main role. In Colombia, primary resistance as a consequence of the use of these two antibiotics and excessive levofloxacin use is above the accepted limit (13.6%, 83%, and 16%, respectively). Despite this fact, empirical therapies that include the combination of these antibiotics are used in patients with previous therapeutic failure. Objective: To determine antibiotic resistance in patients previously treated for H. pylori in Bogotá, Colombia. Materials and methods: We conducted a descriptive study that included ten isolates obtained from five patients with three or four previous failed treatments for H. pylori. Antibiotic resistance to amoxicillin, clarithromycin, levofloxacin, and metronidazole was investigated by agar dilution and confirmed by DNA sequencing (Magrogen, Korea). Results: Eight isolates were resistant to two or more antibiotics. All isolates were resistant to levofloxacin. Susceptibility patterns in isolates from the gastric antrum and the body of the stomach were different in three patients. Conclusion: As far as we know, this is the first evidence of multiple H. pylori resistance in Colombia in previously treated patients. Results demonstrated the consequences of using an ineffective antibiotic scheme and the need to assess antibiotic susceptibility in different anatomical sites of the stomach. The consequences of multiple resistance decrease possible antibiotic effectiveness to eradicate H. pylori in the future.

Introducción. La resistencia a los antibióticos es la principal causa del fracaso del tratamiento contra Helicobacter pylori; la claritromicina y el metronidazol son los antibióticos que generan mayor resistencia. En Colombia, la resistencia primaria a estos dos antibióticos y el uso excesivo de levofloxacina han alcanzado los límites aceptados (13,6, 83 y 16 %, respectivamente). A pesar de ello, se usa el tratamiento empírico combinando estos antibióticos en pacientes en los que ha fallado anteriormente. Objetivo. Determinar la resistencia a los antibióticos en pacientes previamente tratados para H. pylori en Bogotá, Colombia. Materiales y métodos. Se llevó a cabo un estudio descriptivo en el que se evaluó mediante dilución en agar la resistencia a la amoxicilina, la claritromicina, la levofloxacina y el metronidazol en 10 aislamientos provenientes de 5 pacientes con tres o cuatro tratamientos fallidos para H. pylori. La resistencia a los antibióticos se confirmó mediante secuenciación de ADN (Magrogen, Korea). Resultados. Ocho de los aislamientos presentaron resistencia a dos o más antibióticos y todos fueron resistentes a la levofloxacina. Los patrones de sensibilidad de los aislamientos provenientes del antro pilórico y del cuerpo del estómago, fueron diferentes en tres de los pacientes. Conclusión. Hasta donde se sabe, esta es la primera evidencia de resistencia múltiple de H. pylori en Colombia en pacientes previamente tratados. Los resultados evidenciaron las consecuencias del uso de un esquema ineficaz de tratamiento antibiótico y la necesidad de evaluar la sensibilidad a los antibióticos en diferentes sitios anatómicos del estómago. La resistencia múltiple limita el número de antibióticos útiles para erradicar H. pylori.

Correlation among fecal indicator bacteria and physicochemical parameters with the presence of Helicobacter pylori DNA in raw and drinking water from Bogotá, Colombia.

BACKGROUND: The quality of raw and drinking water is a matter of considerable concern due to the possibility of fecal contamination. To assess the quality and public health risk of different types of water, the fecal indicator bacteria (FIB) are used. However, some pathogens, such as Helicobacter pylori, may be present in water when FIB cannot be found. H pylori is recognized as the causative agent of chronic gastritis, peptic and duodenal ulcers, and gastric cancer. The aim of this study was to evaluate the relationships among physicochemical parameters, FIB concentrations, and the presence of H pylori DNA in raw and drinking water from Bogotá, Colombia. MATERIALS AND METHODS: A total of 310 water samples were collected 1 day per week from July 2015 to August 2016, and physicochemical parameters (pH, turbidity, conductivity, and residual free chlorine) were measured. Presence of H pylori DNA was determined and quantified by quantitative polymerase chain reaction (qPCR). Fecal indicator bacteria (total coliforms, Escherichia coli, and spores of sulfite-reducing Clostridia) were enumerated by using standard culture techniques. RESULTS: Thirty of 155 (31%) raw water samples and forty-eight of 155 (38.7%) drinking water samples were positive for the presence of H pylori. No statistically significant relationships were found between physicochemical parameters or FIB with the presence or absence of H pylori in any sample (P < 0.05). CONCLUSIONS: This study provides evidence of the presence of H pylori DNA in raw and drinking water in Bogotá, and shows that the detection and enumeration of FIB and physicochemical parameters in water do not correlate with the risk of contamination with H pylori.

Detection of Helicobacter pylori in drinking water treatment plants in Bogotá, Colombia, using cultural and molecular techniques.

Helicobacter pylori is one of the most common causes of chronic bacterial infection in humans, and a predisposing factor for peptic ulcer and gastric cancer. The infection has been consistently associated with lack of access to clean water and proper sanitation. H. pylori has been detected in surface water, wastewater and drinking water. However, its ability to survive in an infectious state in the environment is hindered because it rapidly loses its cultivability. The aim of this study was to determine the presence of cultivable and therefore viable H. pylori in influent and effluent water from drinking water treatment plants (DWTP). A total of 310 influent and effluent water samples were collected from three drinking water treatment plants located at Bogotá city, Colombia. Specific detection of H. pylori was achieved by culture, qPCR and FISH techniques. Fifty-six positive H. pylori cultures were obtained from the water samples. Characteristic colonies were covered by the growth of a large number of other bacteria present in the water samples, making isolation difficult to perform. Thus, the mixed cultures were submitted to Fluorescent in situ Hybridization (FISH) and qPCR analysis, followed by sequencing of the amplicons for confirmation. By qPCR, 77 water samples, both from the influent and the effluent, were positive for the presence of H. pylori. The results of our study demonstrate that viable H. pylori cells were present in both, influent and effluent water samples obtained from drinking water treatment plants in Bogotá and provide further evidence that contaminated water may act as a transmission vehicle for H. pylori. Moreover, FISH and qPCR methods result rapid and specific techniques to identify H. pylori from complex environmental samples such as influent water.

Eficacia de la terpia triple y cuadruple en helicobacter pylori y descripción de la resistencia a los principales antimicrobianos / Efficacy of triple and quadruple therapy in helicobacter pylori and description of resistance to antimicrobials

Helicobacter pylori es una bacteria gram negativa que infecta a más del 50 % de la población mundial. Su erradicación sigue siendo un reto, sobre todo por el aumento significativo de la prevalencia de la resistencia a los antibióticos como causa fundamental de fracaso terapéutico. Aunque el protocolo ideal de tratamiento no ha sido bien definido, se considera que el umbral de respuesta a la terapia de erradicación no debe ser inferior al 80 %. Es por esto que el presente estudio tiene como objetivo revisar literatura a nivel mundial desde el año 2010 al 2015, para evaluar la eficacia de la terapia triple y cuádruple para la erradicación del H. pylori en relación a la duración del tratamiento y la resistencia de la prevalencia a los principales antimicrobianos.

Helicobacter pylori is a gram-negative bacterium that directly infects more than 50 % of world population Eradicate it or diminish its increasing prevalence is still a challenge because its presence is still related with failed antibiotic treatments that create resistance. Despite there isn't an ideal protocol for its treatment, the threshold of response to eradication therapy should not be less than 80%. This study compilates world bibliographic information from 2010 to 2015; and it was made to determinate triple and quadruple therapy efficiency in H. pylori eradication, relating, treatment length, prevalence and resistance for the principal antimicrobial agents.

Avances en la búsqueda de la vacuna contra Helicobacter pylori / Advances in the search for the Helicobacter pylori vaccine

Resumen Helicobacter pylori es una bacteria que infecta la mucosa gástrica de alrededor de la mitad de la población mundial y está involucrada en la patogénesis de un gran número de enfermedades gástricas y extragástricas en el huésped. Varios antígenos, adyuvantes y rutas de inmunización han sido evaluados buscando una vacuna que ayude a prevenir o erradicar la infección, consiguiéndose diferentes grados de éxito, si bien la inmunidad esterilizante solo se ha conseguido en algunos modelos animales. Varios mecanismos se han propuesto para explicar los resultados obtenidos con las vacunas potenciales evaluadas y para explicar cómo esta bacteria elude la respuesta inmune inducida por ella misma o por intentos de inmunización. El panorama hasta el momento, si bien no parece sencillo, no deja de ser esperanzador por los favorables resultados que vendrían tras la obtención de una vacuna eficaz y por algunos estudios que motivan a la posibilidad de su consecución. MÉD.UIS. 2017;30(3):111-20.

Abstract Helicobacter pylori is a bacteria that infects the gastric mucosa of around half of the world's population and it's implicated in the pathogenesis of various gastric and extragastric diseases in the infected host. Several antigens, adyuvants and routes of immunization have been tested in order to find a vaccine that helps in the control of this bacteria, with varying degrees of success so far, however, sterilizing immunity has been achieved only in animals. Various mechanisms have been proposed to explain the outcomes obtained by testing the potential vaccines and to understand how this bacteria avoids the immunity triggered by itself or by the vaccines tested so far. The current picture does not seem easy but it's still encouraging since some studies have given hope to the possibility of achieving an effective vaccine. MÉD.UIS. 2017;30(3):111-20.

Frecuencia de mutaciones de la nitrorreductasa RdxA de Helicobacter pylori para la activación del metronidazol en una población del departamento del Cauca, Colombia / Frequency of Helicobacter pylori nitroreductase RdxA mutations for metronidazole activation in a population in the Cauca Department, Colombia

RESUMEN Introducción. La resistencia al metronidazol es un factor clave relacionado con el fracaso del tratamiento contra la infección por Helicobacter pylori asociada, principalmente, con mutaciones en la nitrorreductasa RdxA. A pesar de su importancia, los estudios sobre esta proteína son aún incipientes en Popayán, Colombia. Objetivo. Evaluar la frecuencia de las mutaciones en la nitrorreductasa RdxA en una población de pacientes con enfermedad gastrointestinal por H. pylori. Materiales y métodos. El ADN de 170 biopsias gástricas se amplificó mediante reacción en cadena de la polimerasa (PCR) para detectar las mutaciones en la nitrorreductasa RdxA. Se analizaron las secuencias traducidas a aminoácidos y se compararon con la cepa de referencia 26695. Resultados. La frecuencia de mutaciones de la nitrorreductasa RdxA en la población de estudio fue de 78 %. Su distribución más frecuente se detectó en las posiciones D59N (en 153 muestras), R131K (en 101 muestras), R90K (en 97 muestras), A118T (en 42 muestras), I160F (en 32 muestras), H97T (en 26 muestras) y en los codones de parada Q50*; D59*; E75*; C159* y I160* en cinco, una, tres, diez y seis muestras, respectivamente. El genotipo de virulencia más frecuente fue el vacAs1/m1 negativo para cagA (48,6 %). Conclusiones. La gran frecuencia de mutaciones en la nitrorreductasa RdxA en aislamientos de H. pylori en Popayán sugiere que los tratamientos empíricos con metronidazol no serían una opción válida para su erradicación en pacientes de la población estudiada.

ABSTRACT Introduction: Resistance to metronidazole is a key factor associated with Helicobacter pylori treatment failure. Even though resistance is mostly associated with RdxA nitroreductase mutations, studies of this H. pylori protein in Popayán (Colombia) are still incipient. Objective: To evaluate the frequency of mutations in the RdxA nitroreductase in a population of patients with H. pylori-positive gastrointestinal disease. Materials and methods: We amplified the DNA of 170 gastric biopsies by PCR to detect mutations in the RdxA nitroreductase. An analysis of DNA sequences translated into amino acid sequences was done and then compared to the reference strain 26695. Results: The frequency of RdxA nitroreductase mutations in this study population was 78%. Its most frequent distribution was found in positions D59N (153 samples), R131K (101 samples), R90K (97 samples), A118T (42 samples), I160F (32 samples) and H97T (26 samples), and meaningful stop codons Q50*, D59*; E75*, C159* and I160* in five, one, three, ten and six samples, respectively. The most common virulence genotype was vacAs1/m1 cagA negative (48.6 %). Conclusions: The high frequency of RdxA nitroreductase mutations in H. pylori isolates in Popayán (Colombia) indicates that empirical therapy with metronidazole may not be a valid option for the eradication of H. pylori in patients of the studied population.

[Frequency of Helicobacter pylori nitroreductase RdxA mutations for metronidazole activation in a population in the Cauca Department, Colombia].

INTRODUCTION: Resistance to metronidazole is a key factor associated with Helicobacter pylori treatment failure. Even though resistance is mostly associated with RdxA nitroreductase mutations, studies of this H. pylori protein in Popayán (Colombia) are still incipient. OBJECTIVE: To evaluate the frequency of mutations in the RdxA nitroreductase in a population of patients with H. pylori-positive gastrointestinal disease. MATERIALS AND METHODS: We amplified the DNA of 170 gastric biopsies by PCR to detect mutations in the RdxA nitroreductase. An analysis of DNA sequences translated into amino acid sequences was done and then compared to the reference strain 26695. RESULTS: The frequency of RdxA nitroreductase mutations in this study population was 78%. Its most frequent distribution was found in positions D59N (153 samples), R131K (101 samples), R90K (97 samples), A118T (42 samples), I160F (32 samples) and H97T (26 samples), and meaningful stop codons Q50*, D59*; E75*, C159* and I160* in five, one, three, ten and six samples, respectively. The most common virulence genotype was vacAs1/m1 cagA negative (48.6 %). CONCLUSIONS: The high frequency of RdxA nitroreductase mutations in H. pylori isolates in Popayán (Colombia) indicates that empirical therapy with metronidazole may not be a valid option for the eradication of H. pylori in patients of the studied population.

Inhibición del crecimiento de Erwinia chrysanthemi a diferentes concentraciones de ácido fólico: posible uso del ácido fólico como agente bacteriostático y fortificante de la papa Solanum tuberosum / Inhibition of Erwinia chrysanthemi growth to different concentrations of folic acid: possible use of folic acid as bacteriostatic agent and fortifying of Solanum tuberosum potato

Resumen Introducción: Las enterobacterias del genero Erwinia spp producen enfermedades en la papa, un tubérculo de consumo masivo. La regulación de la metilación del DNA puede regular la proliferación de la Erwinia, de tal modo que las concentraciones del ácido fólico, pueden tener un efecto en la capacidad patógena del microorganismo. De otra parte, el ácido fólico previene la aparición de defectos del tubo neural en humanos. Objetivo: Evaluar al ácido fólico como un agente bacteriostático de la Erwinia y que a su vez sea parte de la fortificación de alimentos de consumo masivo como la papa. Materiales y métodos: Se llevó a cabo la caracterización bioquímica de la Erwinia chrysanthemi, se estudió su crecimiento frente a diferentes concentraciones de ácido fólico Resultados: Al aumentar las concentraciones de la vitamina, desde 0,3 µg/L hasta 6,8 µg/L se inhibe el crecimiento bacteriano de la Erwinia chrysanthemi. La vitamina inhibe el crecimiento en cultivo de Erwinia chrysanthemi y actúa como como agente bacteriostático, aspecto es de gran relevancia dado que teóricamente, si la papa estuviera fortificada con el micronutriente, este actuaría contra el agente infeccioso y al mismo tiempo contribuiría al consumo adecuado de la vitamina en la población general.

Abstract Introduction: The enterobacteria of the Erwinia spp genus produce disease in potatoes, which is a tuber of mass consumption. The regulation of DNA methylation can regulate the proliferation of Erwinia in such a way that the concentrations of folic acid may have an effect on the microorganism pathogenic ability. On the other hand, the folic acid prevents the appearance of neural tube defects in humans. Objective: To evaluate folic acid as a bacteriostatic agent of Erwinia and, at the same time, as part of the fortification of mass consumption food such as the potatoes. Materials and methods: The biochemical characterization of the Erwinia chrysanthemi was carried out and its growth compared to different concentrations of folic acid was studied. Results: When increasing the concentrations of the vitamin from 0.3 µg/L up to 6.8 µg/L, the bacterial growth of Erwinia chrysanthemi is inhibited. The vitamin inhibits the growth in cultivation of Erwinia chrysanthemi and acts as a bacteriostatic agent. This aspect is of great importance given that, theoretically, if potatoes were fortified with micro-nutrient, this would act against the infectious agent and, at the same time, contribute to the adequate intake of the vitamin in the general population.

Impacto de las medidas generales en el tratamiento del reflujo gastroesofágico: una revisión basada en la evidencia / Evidence Based Review of the Impact of Treatments of Gastroesophageal Reflux Disease

Contexto: la enfermedad por reflujo gastroesofágico (ERGE) es una patología muy prevalente en adultos que altera la calidad de vida. Se han investigado múltiples tratamientos, algunos de ellos son cambios en el estilo de vida, dado que se han descrito algunos factores de riesgo asociados. El cambio en el estilo de vida es recomendado, sin embargo la evidencia que la soporta es controvertida y escasa. Objetivo: estimar el impacto que tienen los cambios en el estilo de vida en los pacientes con ERGE. Metodología: se realizó un búsqueda sistemática de la literatura en 3 bases de datos (PubMed, ScienceDirect y Embase) y se utilizaron las palabras claves "gastroesophagueal reflux", "heartburn", "bed head elevation", "Carbonated Beverages", "mint", "cacao", "citrus", "alcohol drinking", "caffeine", "coffee", "late-evening meal", "spicy food", "fatty foods", "obesity", "weight loss", "exercise" y "Smoking Cessation". Se incluyeron ensayos clínicos controlados y estudios de cohortes prospectivos que hayan estudiado una intervención en el estilo de vida sobre y evaluado su efecto sobre la ERGE. Resultados: se encontraron 2731 artículos, de los cuales 15 fueron incluidos para ser analizados. Suspender algunos alimentos o bebidas como la menta, el chocolate, cítricos, bebidas carbonatadas, comidas grasas y picantes para mejorar la clínica de la ERGE carece de evidencia. Tomar café descafeinado podría disminuir la cantidad de reflujo. Dejar de fumar se asoció con mejoría de la sintomatología. El horario de la comida en la noche puede alterar algunos parámetros de la pH-metría pero no modificó los síntomas. Algunos ejercicios, principalmente respiratorios podrían mejorar la sintomatología. La elevación de la cabecera de la cama y disminuir de peso en pacientes en sobrepeso/obesos tienen evidencia a favor de la mejoría de los síntomas, sin embargo cuentan con evidencia en contra y limitaciones metodológicas. Conclusión: los cambios en el estilo de vida para mejorar la ERGE no cuentan con evidencia adecuada, existen principalmente ensayos clínicos no controlados o estudios observacionales. Se necesitan más ensayos clínicos y de mejor calidad para definir el impacto de estas medidas en la ERGE.

Background: Gastroesophageal reflux disease (GERD) is a very prevalent disease among adults that alters the quality of life. Many treatments have been investigated, some of which require changes in lifestyle related to associated risk factors. Although changes in lifestyle are recommended, the evidence that supports these recommendations is controversial and scarce. Objective: The objective of this study is to estimate the impact of lifestyle changes on patients with GERD. Methodology: A systematic search of the literature in PubMed, Science Direct and Embase was conducted using the following keywords: gastroesophagueal (sic) reflux, heartburn, bed head elevation, Carbonated Beverages, mint, cocoa, citrus, Drinking Alcohol, caffeine, coffee, late-evening meal, spicy food, fatty foods, obesity, weight loss, exercise and Smoking Cessation. Controlled clinical trials and prospective cohort studies that studied lifestyle changes and their effects on GERD were included in the study. Results: Of the 2,731 articles found, fifteen were included in our analysis. There is little evidence that suspending consumption of food or drink items such as peppermint, chocolate, citrus, carbonated beverages, fatty foods and spicy foods clinically improves GERD. Decaffeinated coffee may decrease the amount of reflux, and quitting smoking is associated with improvement in symptoms. Meal times at night can change some parameters of pH monitoring but did not alter symptoms. Some exercises, mainly respiratory, may improve symptoms. There is evidence that elevating the head while in the bed and weight loss (in cases of overweight or obese patients) improve symptoms, but there is also evidence against these methods and studies of them have methodological limitations. Conclusion: Adequate evidence does not exist that changes in lifestyle improve GERD symptoms. Most studies are uncontrolled clinical trials or observational studies. Additional clinical trials with better quality are needed to define the impact of these measures on GERD.

Helicobacter pylori y alteraciones endoscópicas en pacientes con obesidad severa, programados para cirugía bariátrica / Helicobacter pylori and Endoscopic Alterations in Severely Obese Patients Who Have Been Scheduled for Bariatric Surgery

En los pacientes con obesidad severa, la única intervención terapéutica eficaz es la cirugía bariátrica y la más frecuentemente utilizada es el bypass gástrico con reconstrucción en “Y” de Roux (BPGYR). Helicobacter pylori es la causa de la mayoría de úlceras pépticas y de cánceres gástricos. Muchos expertos recomiendan investigar y erradicar rutinariamente la infección antes del BPGYR. En nuestro medio no se ha investigado la prevalencia de H. pylori ni las alteraciones endoscópicas en pacientes programados para BPGYR, por lo cual se decidió realizar el presente trabajo. Materiales y métodos: se incluyeron pacientes adultos con obesidad severa, sin síntomas gastroduodenales, programados para BPGYR y sometidos a endoscopia digestiva alta preoperatoria. Resultados: desde marzo de 2007 a julio de 2014, se incluyeron 83 pacientes. El 87,95% eran mujeres. La edad promedio fue de 46,9±11,4 años (17-62 años). Se encontró H. pylori en el 57,83% (IC 95%: 47,09-66,96), similar a los no obesos. El 60% tenía algún grado de esofagitis erosiva, várices esofágicas en 2 pacientes y GIST en 1 paciente. Ninguno tuvo atrofia severa (OLGA III o IV). Conclusión: todos los pacientes tenían alguna alteración en la endoscopia. De estos, 2 pacientes tenían várices esofágicas. La prevalencia de H. pylori es similar a la de los no obesos. Se recomienda endoscopia alta de rutina en todos los pacientes antes BPGYR.

When the only effective therapeutic intervention for severely obese patients is bariatric surgery, the most frequently used method is a Roux-en-Y gastric bypass (RYGB). Helicobacter pylori (H. pylori) is the cause of most peptic ulcers and gastric cancers. Many experts recommend routine investigation and eradication of the infection before RYGB. The prevalence of H. pylori and endoscopic alterations among patients scheduled for RYGB had not been studied before in our environment, so we decided to conduct this research. Materials and methods: Severely obese adult patients with no gastric symptoms who were scheduled for RYGB and preoperative upper endoscopy were included in this study. Results: From March 2007 to July 2014, 83 patients were included. 87.95% were women. Mean age was 46.9 +/- 11.4 years (17-62 years). H. pylori was found in 57.83% (95% CI 47.09 - 66.96%) which is similar to the percentage of infections found in people who are not obese. 60% had some degree of erosive esophagitis including esophageal varices in two patients, and GIST in one patient. None had severe atrophy (OLGA III or IV). Conclusion: All patients had some alterations found during endoscopy. Two patients had esophageal varices. The prevalence of H. pylori is similar to that among people who are not obese. Routine upper endoscopy is recommended for all patients prior to RYGB.

Improved allele-specific PCR assays for detection of clarithromycin and fluoroquinolone resistant of Helicobacter pylori in gastric biopsies: identification of N87I mutation in GyrA.

Molecular testing can rapidly detect Helicobacter pylori susceptibility using gastric biopsies. Allele-specific polymerase chain reaction (ASP-PCR) was used to identify H. pylori 23S rRNA and gyrA mutation using gastric biopsies from Colombian patients and confirmed by PCR and sequencing of the 23S rRNA and gyrA genes. The sensitivity and specificity of ASP-PCR were compared with susceptibilities measured by agar dilution. Samples included gastric biopsies from 107 biopsies with H. pylori infections and 20 H. pylori negative. The sensitivity and specificity of ASP-PCR for the 23S rRNA gene were both 100%. The sensitivity and specificity of ASP-PCR for the gyrA gene, published in 2007 by Nishizawa et al., were 52% and 92.7%, respectively; the lower sensitivity was due to the presence of mutation N87I in our samples, which were not detected by the test. In this study, we designed new primers to detect the mutation N87I in GyrA. The ASP-PCR was performed with the original primers plus the new primers. The molecular test with the new primers improved the sensitivity to 100%. In conclusion, ASP-PCR provides a specific and rapid means of predicting resistance to clarithromycin and levofloxacin in gastric biopsies.

[Determination of single nucleotide mutations in the 23S rRNA gene of Helicobacter pylori related to clarithromycin resistance in a population from Cauca, Colombia]. / Determinación de mutaciones de un solo nucleótido en el gen 23S rRNA de Helicobacter pylori relacionadas con resistencia a claritromicina en una población del departamento del Cauca, Colombia.

INTRODUCTION: Antibiotic combination therapy for the eradication of Helicobacter pylori should be based on local resistance patterns. OBJECTIVE: To d etermine the resistance of H. pylori to clarithromycin in a population from Cauca province, through the identification of mutations in the 23S rRNA gene in DNA from gastric biopsies. MATERIALS AND METHODS: A total of 162 patients with functional dyspepsia were included in the study. The 23S rRNA gene and the DNA from 162 gastric specimens were amplified by PCR, and the mutation pattern was identified by direct sequencing. RESULTS: The frequency of clarithromycin resistance was 4%. A2143G mutation was found in four patients (2.46%) and A2142G mutation was found in three patients (1.85%). CONCLUSIONS: Our study shows that the most frequent genotype in H. pylori -positive specimens was A2143G, followed by A2142G. The observed resistance prevalence of H. pylori was low; thus, we consider that clarithromycin treatment is a valid option for H. pylori eradication in the study population.

Determinación de mutaciones de un solo nucleótido en el gen 23S rRNA de Helicobacter pylori relacionadas con resistencia a claritromicina en una población del departamento del Cauca, Colombia / Determination of single nucleotide mutations in the 23S rRNA gene of Helicobacter pylori related to clarithromycin resistance in a population from Cauca, Colombia

Introducción. La terapia antibiótica combinada para la erradicación de Helicobacter pylori debería basarse en los patrones locales de resistencia. Objetivo. Determinar la resistencia de H. pylori a claritromicina en una población del departamento del Cauca mediante la identificación de mutaciones en el gen 23S r RNA en ADN obtenido de biopsias gástricas. Materiales y métodos. Se incluyeron en el estudio 162 pacientes con dispepsia funcional. El gen 23S rRNA se amplificó por PCR y el patrón de mutaciones se identificó por secuenciación directa. Resultados. La frecuencia de resistencia a claritromicina fue de 4 %. La mutación A2143G del gen se encontró en cuatro pacientes (2,46 %) y la mutación A2142G, en tres pacientes (1,85 %). Conclusiones. El estudio encontró que el genotipo más frecuente en los especímenes positivos para H. pylori fue 2143G, seguido por A2142G. La prevalencia observada de resistencia de H. pylori fue baja; por lo tanto, se considera que el tratamiento con claritromicina es una opción válida para la erradicación de H. pylori en la población objeto de estudio.

Introduction: Antibiotic combination therapy for the eradication of Helicobacter pylori should be based on local resistance patterns. Objective: To d etermine the resistance of H. pylori to clarithromycin in a population from Cauca province, through the identification of mutations in the 23S rRNA gene in DNA from gastric biopsies. Materials and methods: A total of 162 patients with functional dyspepsia were included in the study. The 23S rRNA gene and the DNA from 162 gastric specimens were amplified by PCR, and the mutation pattern was identified by direct sequencing. Results: The frequency of clarithromycin resistance was 4%. A2143G mutation was found in four patients (2.46%) and A2142G mutation was found in three patients (1.85%). Conclusions: Our study shows that the most frequent genotype in H. pylori -positive specimens was A2143G, followed by A2142G. The observed resistance prevalence of H. pylori was low; thus, we consider that clarithromycin treatment is a valid option for H. pylori eradication in the study population.

Phenotypic and genotypic analysis of clarithromycin-resistant Helicobacter pylori from Bogotá D.C., Colombia.

Resistance of Helicobacter pylori to clarithromycin is the most common cause of treatment failure in patients with H. pylori infections. This study describes the MICs and the presence of 23S rRNA mutations of H. pylori isolates from Bogotá, D.C., Colombia. H. pylori were isolated from gastric biopsies from patients with functional dyspepsia. Clarithromycin susceptibility was investigated by agar dilution and strains were considered resistant if the MIC was ≥ 1 µg/ml. DNA sequences of the 23S rRNA gene of strains resistant and sensitive to clarithromycin were determined to identify specific point mutations. Clarithromycin resistance was present in 13.6% of patients by agar dilution. The A2143G, A2142G and A2142C mutations were found in 90.5, 7.1, and 2.4% of H. pylori strains with resistance genotype.The resistant phenotype was associated with 23S rRNA resistance genotype in 85.7% of isolates. The point mutations in 23S rRNA were well correlated with MICs values for clarithromycin.

Detection of clarithromycin resistance in Helicobacter pylori following noncryogenic storage of rapid urease tests for 30 days.

OBJECTIVE: Traditional Helicobacter pylori (H. pylori) eradication therapy has been undermined by increasing antimicrobial, especially clarithromycin, resistance. Susceptibility testing in some areas is difficult to achieve or unavailable. We aimed to determine whether gastric biopsy specimens stored at room temperature for rapid urease test (RUT) were suitable for clarithromycin susceptibility testing of H. pylori. METHODS: After 30 days of storage at room temperature, DNA was extracted from gastric biopsies present in RUTs (Hpfast). H. pylori status and clarithromycin susceptibility were evaluated using H. pylori-specific polymerase chain reaction (PCR) for ureA, vacA, and allele-specific primer-PCR of the 23S rRNA genes. The PCR results were compared with histology, RUT, and culture results. H. pylori positive was defined as RUT and either culture or histology positive; H. pylori negative as RUT, culture and histology negative. RESULTS: Samples from 31 patients were evaluated; 11 were H. pylori positive including 9 by culture; seven of which had allele-specific primer-PCR results from the RUT specimen for the detection of mutations of the 23S rRNA gene. When both tests were available, culture and PCR results were concordant in 7 cases. In 15 of the 20 histology, RUT and culture negative patients, three PCR were negative. In one patient, all of the three tests were positive; and in three only the 23S rRNA was positive and in one only ureA was positive. CONCLUSION: Gastric biopsy specimens stored in the gel of RUT for 30 days can be used for molecular testing to confirm the diagnosis of H. pylori infection and test for clarithromycin susceptibility.

Sequential statistical improvement of the liquid cultivation of Helicobacter pylori.

BACKGROUND: Colonization of the gastric mucosa by Helicobacter pylori is one of the most important causes of acute and chronic gastric pathologies in humans. Achieving the growth of H. pylori in liquid media is of great importance in the development of clinical studies. In this study, we developed a sequential optimization strategy based on statistical models to improve the conditions of liquid culture of H. pylori. MATERIALS AND METHODS: Four statistical models were sequentially used. First, a Box-Behnken design was used to select the best process conditions (shaking speed, inoculum concentration, and final volume of culture). Secondly, a general factorial design was used to evaluate the influence of adding gel blocks or gel beads (shape and composition). Then a D-optimal reduce design was carried out to allow the selection of the most influential factors in increasing the cell concentration (culture media components). Finally, another Box-Behnken design was used to optimize the concentration of the culture media components previously selected. RESULTS: After 12 hours of liquid culture a concentration of 25 x 10(8) cells per mL (9.4 log(10) cells per mL) of H. pylori was obtained, compared with a predicted 32 x 10(8) (9.5 log(10) cells per mL), which means between 1 and 5 log(10) units higher than some previous reports. CONCLUSIONS: The sequential statistical approach increased the planktonic H. pylori cell culture. The final culture media and conditions were: Brain Heart Infusion, blood agarose (1.5% w/v), lamb's blood (3.18% v/v), DENT (0.11% v/v), and Vitox (0.52% v/v) at 60 rpm and 37 degrees C with filtered CO2 (5% v/v) bubbled directly into the culture media in a final volume of 76.22 mL.

Resistencia de Helicobacter pylori a metronidazol, claritromicina y amoxicilina en pacientes colombianos / Helicobacter pylori resistance to metronidazole, clarithromycin and amoxicillin in Colombian patients

Helicobacter pylori (H. pylori) es un patógeno universal, que infecta a más de la mitad de la población mundial. En las últimas dos décadas, el tratamiento recomendado para su erradicación, como esquema de primera línea, es la triple terapia estándar, constituida por un inhibidor de la bomba de protones, amoxicilina y claritromicina o metronidazol. En los últimos años la eficacia de esta terapia ha declinado, debido especialmente a la resistencia de la bacteria a metronidazol y a claritromicina. Objetivos: En este estudio, se evaluó la prevalencia de resistencia primaria de cepas colombianas de H. pylori a metronidazol, claritromicina, amoxicilina. Además, se analizaron los genotipos de vacA y cagA de las cepas aisladas y la correlación entre los marcadores de virulencia y la resistencia a claritromicina, amoxicilina y metronidazol. Métodos: La resistencia a metronidazol, amoxicilina y claritromicina fue determinada por el método de E-test. Se extrajo el ADN genómico y variantes alélicas de vacA y cagA fueron identificadas por la técnica de reacción en cadena de la polimerasa (PCR). Resultados: La resistencia a metronidazol fue de 81,01% (IC 95% 70,3%-88,6%), a amoxicilina de 3,8% (IC 95% 0-8,6%) y a claritromicina de 17,72% (IC 95% 10,37-28,29). No se encontró asociación significativa entre el genotipo de patogenicidad y la resistencia o susceptibilidad a los antimicrobianos cuando los valores de CIM de cada antibiótico se compararon con los diferentes genotipos cagA y vacA. Conclusión: Encontramos una alta tasa de resistencia a los tres principales antibióticos utilizados en la mayoría de los esquemas exitosos de erradicación de la infección, lo cual implica la necesidad de investigar, con prioridad, nuevos esquemas de tratamiento para la erradicación de la infección en Colombia.

Helicobacter pylori (H. pylori), is a universal pathogen that infects more than half the world population. In the last two decades, the recommended treatment for its eradication, as first-line scheme is the standard triple therapy, consisting of an inhibitor of the proton pump, clarithromycin and amoxicillin or metronidazole. In recent years the effectiveness of this therapy has declined, especially due to the resistance of bacteria to metronidazole and clarithromycin. Objectives: In this study, we evaluated the prevalence of primary resistance of Colombian H. pylori isolates to metronidazole, clarithromycin, amoxicillin. In addition, the vacA and cagA genotypes of strains isolated were determined and associated to correlate the virulence markers and antibiotic resistance. Methods: Minimum inhibitory concentration (MIC) for metronidazole, clarithromycin and amoxicillin were determined by E-test method. Genomic DNA was extracted, and allelic variants of vacA and cagA were identified by the polymerase chain reaction (PCR). Results: Resistance to metronidazole was 81.01 % (IC95% 70.3%-88.6%), to amoxicillin 3,8% (IC 95% 0-8,6%), and to clarithromycin 17.72% (IC95% 10.37-28.29). No significant correlation between pathogenicity and resistance or susceptibility was detected when MIC values for each antibiotic were compared with different vacA and cagA genotypes. Conclusion: We find a high rate of resistance to three principal antibiotics used in the majority of the successful schemes of eradication of the infection, which implies the need to investigate with priority new schemes of treatment for the eradication of the infection in Colombia.