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.

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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.

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.

Objective Traditional Helicobacter pylori (H. pylori) eradication therapy has been undermined by increasing antimicrobial, especially clarithromycin, resistance. Susceptibility testing in most areas is difficult or unavailable. We assessed whether gastric biopsies stored at room temperature in a rapid urease test were suitable for H. pylori clarithromycin susceptibility testing. Methods After 30 days of storage at room temperature, DNA was extracted from a gastric biopsy present within a rapid urease test (Hpfast). H. pylori status and clarithromycin susceptibility were evaluated used H. pylori-specific PCR for ureA, vacA, and allele-specific primer-polymerase chain reaction of the 23S rRNA genes. The PCR results were compared with histology, RUT, and culture. 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 subjects were evaluated; 11 were H. pylori positive including 9 by culture; 8 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 8/8 (100%). Fifteen of the 20 histology, RUT and culture negative cases had all 3 PCR’s negative. In one all 3 were positive; in 3 only the 23S rRNA was positive and in 1 only ureA was positive. Conclusion Gastric biopsy specimens stored within the gel of an RUT for 30 days can be used to for molecular testing confirm the diagnosis of H. pylori infection and test for clarithromycin susceptibility.

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 .

Objetivo. Determinar la frecuencia de Listeria spp., en quesos frescos costeños, distribuidos en plazas de mercado populares de las ciudades de Montería y Cereté. Materiales y métodos. Teniendo en cuenta la importancia económica de esta zona ganadera para Colombia se tomaron 217 muestras entre Junio y Agosto de 2005, los aislamientos obtenidos fueron identificados por pruebas bioquímicas presuntivas, PCR-Múltiple (L1-U1/LF-LR) y pruebas bioquímicas para confirmación de especie. Adicionalmente, se determinó la frecuencia de las especies del género y se caracterizó la resistencia antimicrobiana de las cepas de mayor frecuencia. Resultados. Las pruebas bioquímicas y la PCR detectaron 49 aislamientos positivos para Listeria (22.58%), de los cuales 16.33% (8/49) correspondieron a Montería y 24.40% (41/168) a Cereté. La frecuencia por especies fue 14.75% para L. ivanovii, 2.30% para L. innocua, 1.84% para L. welshimeri y 1.38% para L. seeligeri, no se detectó L. monocytogenes. Sólo 3/32 cepas de L. ivanovvi (9.38%) mostraron resistencia a penicilina, estreptomicina y eritromicina respectivamente. Conclusiones. Los resultados confirman que los quesos costeños están frecuentemente contaminados con Listeria spp. La presencia de L. ivanovii patógeno involucrado en algunos casos de infecciones oportunistas en humanos y L. innocua; microorganismo utilizado en muchas industrias de alimento como indicador del grado o calidad de sanitización; demuestra que las condiciones de producción y expendio no son adecuadas y que el consumo de queso costeño no es seguro. La resistencia antimicrobiana aunque baja muestra posibilidades para la transmisión horizontal y/o vertical de los genes de resistencia.

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.