[Show abstract][Hide abstract] ABSTRACT: Helicobacter pylori gastric colonization is known to be high in symptomatic subjects. However, only a few reports on the presence of H. pylori in the esophageal mucosa have been published. The aim of this study was to assess the frequency of H. pylori in the esophagus of dyspeptic patients and its association with histopathology.
The presence of H. pylori in the gastroesophageal mucosa was detected by fluorescence in situ hybridization (FISH) and PCR analysis of DNA extracted from gastric and esophageal biopsies of 82 symptomatic patients, using genus- and species-specific PCR primers. Alterations in the gastroesophageal mucosa were assessed by conventional histological techniques.
H. pylori in the stomach was detected by PCR and FISH, respectively, in 61% (n=43) and 90% (n=63) of dyspeptic patients, and in the esophagus in 70% (n=44) and 73% (n=46). The prevalence of cagA-positive strains by PCR varied from 50% (n=35) in the gastric mucosa to 65% (n=41) in the esophageal mucosa. By combining the results of both methods, H. pylori was present in the gastroesophageal mucosa in 86% (n=68) of patients. The association of the presence of bacteria, including H. pylori, in the esophageal mucosa with histopathological alterations was statistically significant between microabscesses and bacteria (r=0.656, p<0.0001) and PCR detection and pseudogoblet cells (r=0.25, p<0.047).
This is the first report of the occurrence of H. pylori in the esophageal mucosa from dyspeptic Venezuelan patients. These results demonstrate the high prevalence of H. pylori in the esophagus, and its presence was correlated with signs of inflammation.
International journal of infectious diseases: IJID: official publication of the International Society for Infectious Diseases 03/2012; 16(5):e364-70. · 2.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to characterize the virulence properties and the antimicrobial resistance of Vibrio cholerae isolates from a coastal area of the Caribbean Sea. Three V. cholerae isolates were obtained from seawater and plankton using the HP selective medium for Helicobacter pylori. These V. cholerae isolates belonged to the non-O1, non-O139 serogroups and they did not have cholera toxin genes. They were resistant to penicillins and some cephalosporins and were sensitive to netilmicin, tetracyclines, sulfamethoxazole-trimethoprim and quinolones. This is the first study that provides biochemical and molecular evidence of non-O1, non-O139 V. cholerae isolates, non-toxigenic, carrying antibiotic resistance in seawater and plankton from a coastal area of the Caribbean Sea.
International Journal of Environmental Health Research 05/2009; 19(4):279-89. · 1.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To assess the presence of Helicobacter DNA in the gastric mucosa Thoroughbred horses.
Squamous and glandular mucosa samples were collected from 20 Thoroughbreds. None of these horses had shown any clinical symptoms of gastrointestinal disease. Necropsy tissues were analysed using histopathological techniques and a Helicobacter genus-specific PCR assay followed by sequencing of the amplicons. Seven horses were diagnosed with gastric ulceration, five with gastritis and six with both pathologies. Only two horses had a healthy gastric mucosa. Helicobacter-like DNA was detected in two out of seven horses with gastric ulcers, three out of five horses with gastritis, five out of six horses with both pathologies and one horse with normal gastric mucosa. The sequences of 1195 and 1237 bp fragments of the 16S rRNA gene shared 99% identity with the Helicobacter pylori 16S rRNA gene. However, all the samples were negative when tested with H. pylori-specific PCR assays targeting the cagA and glmM genes.
The Helicobacter genus might colonize the gastric mucosa of horses.
This is the first report of Helicobacter-like DNA in the gastric mucosa of horses and the pathogenic potential of these organisms requires further investigation.
Letters in Applied Microbiology 12/2007; 45(5):553-7. · 1.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The spectrum of human non-pylori Helicobacter infections is expanding, with species such as H. heilmannii and H. felis occasionally being associated with gastritis. However, the existence of non-pylori Helicobacter colonization in asymptomatic subjects has not been evaluated. The aim of this study was to investigate whether Helicobacter species other than pylori are present in the upper digestive tract of asymptomatic human subjects.
A Helicobacteraceae-specific semi-nested polymerase chain reaction (PCR) assay was used to detect Helicobacter-like organisms in the upper digestive tract of 91 Venezuelan volunteers (aged 18-68 years, 41 females, 50 males). Species were identified by denaturing gradient gel electrophoresis analysis and sequencing of the PCR products.
We detected DNA sharing 99-100% sequence identity in over 300-400 bp with the 16S rRNA genes of H. pylori, H. cetorum, and Candidatus Wolinella africanus in 76%, 16%, and 15% of the subjects, respectively. Multiple colonization was documented in 10% of the subjects: H. cetorum and Candidatus W. africanus (4%), H. pylori and Candidatus W. africanus (4%), and H. pylori and H. cetorum (2%).
Our results suggest that non-pylori Helicobacteraceae colonization is relatively common in the Venezuelan asymptomatic population. This is the first report documenting the presence of H. cetorum DNA in the human upper digestive tract, and the second report of the recently discovered Candidatus W. africanus.
[Show abstract][Hide abstract] ABSTRACT: This project investigated the utility of HP selective medium to isolate H. pylori cells from seawater and from marine molluscs.
Nested-PCR was performed to reveal the presence of Helicobacter genus. All samples were cultured in HP selective medium and 16 cultures were initially selected as putative Helicobacter. Helicobacter spp. DNA were detected in 9/16 cultures and three of them had 99-100% homology to H. pylori based on 16S RNA gene sequence. Helicobacter pylori isolation was unsuccessful. On the basis of 16S RNA gene sequences the contaminating organisms were shown to be Proteus mirabilis and Vibrio cholerae.
These results indicate the coexistence of three predominant bacterial genera in the cultures and that HP selective medium can grow other enteric bacteria besides Helicobacter. Additional assays will improve the HP selective medium formulation for marine samples avoiding P. mirabilis and V. cholerae interferents.
This work shows the effectiveness of the selective HP medium for the Helicobacter culture from marine samples.
Letters in Applied Microbiology 09/2007; 45(2):213-8. · 1.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The fecal contamination of raw seafood by indicators and opportunistic pathogenic microorganisms represents a public health concern. The objective of this study was to investigate the presence of enteric bacteria colonizing oysters collected from a Venezuelan touristic area. Oyster samples were collected at the northwestern coast of Venezuela and local salinity, pH, temperature, and dissolved oxygen of seawater were recorded. Total and fecal coliforms were measured for the assessment of the microbiological quality of water and oysters, using the Multiple Tube Fermentation technique. Analyses were made using cultures and 16S rRNA gene sequencing. Diverse enrichment and selective culture methods were used to isolate enteric bacteria. We obtained pure cultures of Gram-negative straight rods with fimbriae from Isognomon alatus and Crassostrea rhizophorae. Our results show that P. mirabilis was predominant under our culture conditions. We confirmed the identity of the cultures by biochemical tests, 16S rRNA gene sequencing, and data analysis. Other enterobacteria such as Escherichia coli, Morganella morganii and Klebsiella pneumoniae were also isolated from seawater and oysters. The presence of pathogenic bacteria in oysters could have serious epidemiological implications and a potential human health risk associated with consumption of raw seafood.
Revista do Instituto de Medicina Tropical de São Paulo 01/2007; 49(6):355-9. · 0.96 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Reportamos el caso de un paciente que sufre de síntomas recurrentes de dispepsia desde el año 1997, pero no esta infectado por Helicobacter pylori, el agente etiológico de la gastritis en humanos. El diagnostico de H. Pylori fue realizado por tres métodos: histología, test de ureasa rápido en biopsia gástrica y test de HpSA (Meridian Diagnostics, Italy) en heces. La detección de Candidatus W. africanus fue realizada a partir de ADN de jugo gastroesofagal colectado con un Enterotest (HDC, USA), utilizado un ensayo de PCR con cebadores específicos para el genero Helicobacter. El producto amplificado fue analizado mediante un gel de electroforesis en gradiente desnaturalizante (DGGE) y posteriormente fue secuenciado. Encontramos que este paciente está infectado con Candidatus Wolinella africanus, un posible nuevo patógeno del tracto digestivo humano, el cual ha sido reportado por primera y única vez en Diciembre 2003 en pacientes Surafricanos con cáncer de esófago.
G.E.N.: organo oficial de la Sociedad Venezolana de Gastroenterología, Endocrinología y Nutrición 09/2006; 60(3):205-206.
[Show abstract][Hide abstract] ABSTRACT: La detección de antígenos de Helicobacter pylori en heces permite el diagnóstico no invasivo de la infección por H. pylori así como la evaluación posterior al tratamiento. Recientemente, un nuevo método inmunocromatográfico rápido en heces (Immunocard STAT HpSATM, Meridian Bioscience), ha sido desarrollado para la detección de antígenos de H. pylori en materia fecal utilizando un anticuerpo monoclonal anti-H. pylori. El propósito del presente estudio es validar esta prueba en pacientes venezolanos. Un total de 56 pacientes, presentando síntomas a nivel gastrointestinal superior, participaron voluntariamente. Los resultados obtenidos por Immunocard STAT HpSA en heces fueron comparados con los resultados de PCR en ADN de biopsia gástrica. Ambas pruebas coincidieron en 46 pacientes (21 positivos y 25 negativos para H. pylori). Se obtuvieron 6 falsos positivos y 4 falsos negativos por el método rápido. La sensibilidad, especificidad, valor predictivo positivo y valor predictivo negativo del Immunocard STAT HpSA fueron 84% (IC95%= 64-95), 81% (IC95%= 63-93), 78% (IC95%= 58-91) y 86% (IC95%= 68-96) respectivamente. La sensibilidad y especificidad fueron ligeramente menores a las reportadas en otros estudios. Sin embargo, la facilidad de uso, rapidez de la respuesta y el bajo costo de la prueba HpSA permiten utilizarlo, especialmente en niños, como prueba inicial no invasiva.
[Show abstract][Hide abstract] ABSTRACT: The proteobacterial genus Helicobacter is composed of gastric species, all of them urease-positive, and enteric species (gastrointestinal, intestinal, hepatic, biliary), some of them urease-positive, others not. Here, we point out that the gastric species are divided in at least two phylogenetic groups, one is homogeneous, clearly separated from the enteric species, and another is forming a tight cluster within the enteric species. This feature is apparent in the phylogeny of the genus as inferred from both the 16S rRNA gene and the alpha-subunit of the urease. Our observation shows that the ability to colonize the gastric mucosa appeared more than once in the history of the genus, and suggests that acquiring this ability may be a relatively simple and punctual process, involving a limited number of genes. Such a process may be the lateral transfer acquisition of a functional copy of the gene ureI which encodes a urea channel activated at acidic pH that is essential for gastric colonization by Helicobacter pylori.
Infection Genetics and Evolution 06/2002; 1(3):215-23. · 2.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Gastric Helicobacter species are widespread and have been reported in wild and domestic mammals of different dietary habits such as humans, dogs, cats, macaques, mice, cheetahs, ferrets, swine and cattle. All have been associated with gastric pathologies. Recently, gastric Helicobacter species were shown to be widespread in cattle and swine in Europe, and there is a report of Helicobacter pylori in sheep in Italy. However, there are no reports of Helicobacter infection in the goat, another important domestic animal of human consumption. The aim of our study was to assess whether Helicobacter abomasal infection was common in goats slaughtered for human consumption. Infection was detected through PCR analysis of DNA extracted from gastric biopsies, using genus- and species-specific primers. Bovine and porcine gastric samples were also analyzed as positive controls. None of the 70 goats were positive for Helicobacter spp.; however, Candidatus Helicobacter bovis and Candidatus Helicobacter suis were detected in 85% of the bovine and 45% of the porcine samples, respectively. We discuss the possibility that goats may exhibit natural resistance to abomasal infection by Helicobacter spp.
[Show abstract][Hide abstract] ABSTRACT: Helicobacter pylori has been recognized as a major gastric pathogen. The objective of this study was to assess the diagnostic value of common clinical tests to detect H. pylori infection, by comparison with PCR. Serum and gastric biopsy specimens from 106 dyspeptic patients were examined. Serology was performed with Pyloriset Dry test, and biopsies were examined histologically, for rapid urease activity and PCR amplification of an ureA gene segment of H. pylori. PCR primers were specific for H. pylori and required at least 1.47 pg of H. pylori DNA, corresponding to about 800 bacterial cells. According to serology, histology, rapid urease, and PCR, positive results were respectively found in 56%, 86%, 64%, and 85% of dyspeptic patients, primarily with gastritis. Relative to PCR, the sensitivity (and specificity) was 55% (38%) for serology, 86% (13%) for histology, 70% (69%) for urease. When combining histology and urease, Bayesian analysis of data indicated no advantage of using combined methods over rapid urease test alone. Histology should not any longer be considered a gold standard test for Helicobacter pylori. Urea breath test still seems the first option for non invasive diagnostic. If an invasive diagnostic is justified, highly specific and sensitive molecular methods should be used to examine specimens.