Advances of enzymes related to microbial cement / 生物工程学报

Microbial induced calcium carbonate precipitation (MICP) refers to the natural biological process of calcium carbonate precipitation induced by microbial metabolism in its surrounding environment. Based on the principles of MICP, microbial cement has been developed and has received widespread attention in the field of biology, civil engineering, and environment owing to the merits of environmental friendliness and economic competence. Urease and carbonic anhydrase are the key enzymes closely related to microbial cement. This review summarizes the genes, protein structures, regulatory mechanisms, engineering strains and mutual synergistic relationship of these two enzymes. The application of bioinformatics and synthetic biology is expected to develop biocement with a wide range of environmental adaptability and high performance, and will bring the MICP research to a new height.

Usefulness of rapid urease test samples for molecular analysis of clarithromycin resistance in Helicobacter pylori / Utilidad de las muestras de test rápido de ureasa para el análisis molecular de resistencia a claritromicina en Helicobacter pylori

Helicobacter pylori is a gastric pathogen that is widely recognized as a causative agent of gastric disease. Its eradication is variable, mainly due to increased resistance to clarithromycin. Our objective was: to evaluate (i) if the biopsy specimen used for the rapid urease test is a useful sample to detect resistance to clarithromycin by PCR-RFLP and (ii) the distribution of A2142G and A2143G point mutations in the 23S rRNA gene, in relation to virulence factors in our region. Gastric specimens were collected from adult dyspeptic patients (n = 141) and H. pylori was investigated by the rapid urease test, histopathological analysis and PCR for the hsp60 gene. Clarithromycin resistance was detected by PCR-RFLP in 62 H. pylori (+) paired biopsy specimens submitted to molecular analysis and the rapid urease test. H. pylori virulence factors were analyzed by multiplex PCR using specific primers for the cagA, vacA and babA2 genes. Thirteen out of 62 strains (20.9%) were resistant to clarithromycin: 6/13 (46.2%) harbored the A2143G mutation whereas 7/13 (53.8%) carried the A2142G point mutation. vacA m1s1 was the most frequent genotype among the resistant strains. In conclusion, the biopsy specimens used for the rapid urease test were suitable samples for clarithromycin resistance detection in patients infected with H. pylori, which became especially useful in cases where the number or size of the biopsies is limited. In addition, this is the first report of a molecular analysis for clarithromycin resistance performed directly from gastric biopsies in our region.

Helicobacter pylori es un patógeno ampliamente reconocido como causante de enfermedad gástrica. Su erradicación es variable, principalmente debido al incremento de la resistencia a claritromicina. Nuestros objetivos fueron evaluar la utilidad de la biopsia usada para realizar el test rápido de ureasa en la detección de resistencia a claritromicina por PCR-RFLP y conocer la distribución de las mutaciones puntuales A2142G y A2143G en el gen ARNr 23S, en relación con los factores de virulencia en nuestra región. Se recolectaron muestras gástricas (n=141) provenientes de pacientes adultos dispépticos y se investigó la presencia de H. pylori mediante el test rápido de ureasa, análisis histopatológico y PCR para el gen hsp60. La resistencia a claritromicina se analizó por PCR-RFLP en 62 muestras pareadas de biopsias gástricas H. pylori+ destinadas al análisis molecular y al test rápido de ureasa. Los factores de virulencia de H. pylori fueron analizados mediante PCR multiplex usando oligonucleótidos específicos para los genes cagA, vacA y babA2. Trece de 62 cepas (20,9%) fueron resistentes a claritromicina, 6/13 (46,2%) llevaron la mutación A2143G, mientras que 7/13 (53,8%) presentaron la mutación A2142G. El genotipo vacA s1m1 fue el más frecuente entre las cepas resistentes a claritromicina. En conclusión, las biopsias destinadas al test rápido de ureasa fueron muestras apropiadas para la detección de la resistencia a claritromicina en pacientes infectados con H. pylori. Esto es especialmente útil en aquellos casos en los que el número o el tamaño de las muestras son limitados. Además, este es el primer reporte de estudio de resistencia a claritromicina (mediante técnicas moleculares), directamente de biopsias gástricas en nuestra región.

Validación del test rápido de la ureasa para la detección del Helicobacter pylori en el Hospital Nacional Cayetano Heredia, Lima, Perú / Validation of the rapid urease test for the detection of Helicobacter pylori in a Peruvian hospital

Objetivos: Validar un test rápido de la ureasa (TRU) en el Hospital Cayetano Heredia (HCH) de Lima, Perú Materiales y métodos: Estudio observacional prospectivo. Se incluyó 181 pacientes mayores de 18 años de edad con síntomas dispépticos, que fueron sometidos a endoscopía digestiva alta en el Servicio de Gastroenterología del HCH y que no hubiesen recibido durante las últimas cuatro semanas inhibidores de la bomba de protones (IBPs), bismuto o antibióticos. Se tomó dos biopsias de antro una para hacer el TRU (Sensibacter pylori test®) y otra para anatomía patológica con el fin de determinar la presencia de la infección por H. pylori por ambos métodos. Finalmente se comparó el resultado de la anatomía patológica (patrón de oro) con el de TRU. Resultados: Se evaluó 181 pacientes, la edad promedio fue 52,8±13,5 años. La sensibilidad, especificidad, valor predictivo negativo (VPN), valor predictivo positivo (VPP) a los 20 minutos fueron de 86,8%, 98,5%, 81,5% y 99% y a las 24 horas 97,3%, 99,5%, 95,7% y 99,1% respectivamente. Conclusión: El TRU es un test confiable, accesible y de fácil aplicación para hacer el diagnóstico de la infección por H. pylori.

Objective: To validate a rapid urease test (RUT) in Cayetano Heredia Hospital (HCH) in Lima, Peru. Materials and methods: This is a prospective observational study that included 181 patients over 18 years old with dyspeptic symptoms. All of them underwent upper gastrointestinal endoscopy at the Department of Gastroenterology at HCH. They had not received, during the last four weeks, proton pump inhibitors (PPIs), bismuth or antibiotics. Two biopsies of antrum were taken, one to perform the TRU (Sensibacter pylori test®) and the other one for pathology, in order to determine by both methods the presence of H. pylori infection. TRU’s results were compared with pathology´s (gold standard). Results: 181 patients, average age 52.8±13.5 years, were evaluated. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) at 20 minutes were 86.8%, 98.5%, 81.5% and 99% and at 24 hours 97.3%, 99.5%, 95.7% y 99.1% respectively. Conclusion: The rapid urease test is a reliable, accessible and easy to apply test for the diagnosis of H. pylori infection.

Validación de Sensibacter pylori test® como prueba de ureasa para el diagnóstico de infección por Helicobacter pylori en Chile / Validation of Sensibacter pylori test ® as urease tests for the diagnosis of Helicobacter pylori infection in Chile

Introduction: Helicobacter pylori is a highly prevalent bacterium in Chile that causes various gastric pathologies including gastric cancer, which corresponds to the leading cause of cancer-related death in Chile in men. This is why early detection of an Helicobacter pylori infection is gaining importance, for tis purpose there are various diagnostic methods, including rapid urease tests (RUT) such as the Sensibacter pylori test®. Objectives: To validate the Sensibacter pylori test® in Chile, so that it may be used in healthcare centres in our country. Materials and Methods: Upper gastrointestinal endoscopies were performed on symptomatic patients in 3 healthcare centres and gastric mucosa samples were obtained following established protocols. These underwent the health centre ́s RUT and the Sensibacter pylori test®, and the results were compared to the gastric mucosa histology (gold standard) Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for each test. Kappa test was used to assess agreement between the RUT’s and the turning time of each test was measured. Results: Sensibacter pylori test® showed a sensitivity of 82.6 percent, specificity 92.3 percent, PPV 95 percent and NPV 75 percent. The consistency with the other RUT’s was 0.958 (p < 0.001) and 0.872 (p < 0.001). The turning time was 15 min. Conclusion: Sensibacter pylori test® is a sensitive and specific method, similar to other tests used daily in Chile, which has the advantage of yielding results within a few minutes.

Introducción: Helicobacter pylori es una bacteria de gran prevalencia en Chile y es causante de variadas patologías gástricas, entre las cuales se encuentra el cáncer gástrico, que corresponde a la primera causa de muerte por cáncer en Chile en hombres. Por esto, cobra relevancia detectar a tiempo la existencia de Helicobacter pylori, para lo cual existen diversos métodos diagnósticos, entre los que se encuentran los test rápidos de ureasa (TRU) como Sensibacter pylori test®. Objetivos: Validar Sensibacter pylori test® en Chile, para poder ser utilizado en centros de salud de nuestro país. Materiales y Métodos:Se realizaron endoscopias digestivas altas a pacientes sintomáticos en tres centros de salud y se obtuvieron muestras de mucosa gástrica según protocolos establecidos. Estas se sometieron al TRU del centro de salud y a Sensibacter pylori test®, comparándose el resultado con histología de la mucosa gástrica (estándar de oro), calculándose sensibilidad, especificidad, valor predictivo positivo (VPP) y valor predictivo negativo (VPN). Se utilizó test kappapara evaluar concordancia entre TRU y se midió el tiempo de viraje de cada test. Resultados: Sensibacter pylori test® demostró una sensibilidad de 82,6 por ciento, especificidad de 92,3 por ciento, VPP de 95 por ciento y VPN de 75 por ciento. La concordancia con los otros TRUs fue de 0,958 (p < 0,001) y 0,872 (p < 0,001). El tiempo de viraje fue de 15 min. Conclusión: Sensibacter pylori test® es un método sensible y específico comparable con otros test de uso diario en Chile, y tiene la ventaja de mostrar resultados en pocos minutos.

Correlations between the CagA Antigen and Serum Levels of Anti-Helicobacter pylori IgG and IgA in Children

We tested correlations between anti-Helicobacter pylori IgG and IgA levels and the urease test, anti-CagA protein antibody, degree of gastritis, and age. In total, 509 children (0-15 years) were enrolled. Subjects were stratified as 0-4 years (n = 132), 5-9 years (n = 274), and 10-15 years (n = 103) and subjected to the urease test, histopathology, ELISA, and western blot using whole-cell lysates of H. pylori strain 51. The positivity rate in the urease test (P = 0.003), the degree of chronic gastritis (P = 0.021), and H. pylori infiltration (P < 0.001) increased with age. The median titer for anti-H. pylori IgG was 732.5 IU/mL at 0-4 years, 689.0 IU/mL at 5-9 years, and 966.0 IU/mL at 10-15 years (P < 0.001); the median titer for anti-H. pylori IgA was 61.0 IU/mL at 0-4 years, 63.5 IU/mL at 5-9 years, and 75.0 IU/mL at 10-15 years (P < 0.001). The CagA-positivity rate was 26.5% at 0-4 years, 36.5% at 5-9 years, and 46.6% at 10-15 years for IgG (P = 0.036), and 11.3% at 0-4 years, 18.6% at 5-9 years, and 23.3% at 10-15 years for IgA (P < 0.001). Anti-H. pylori IgG and IgA titers increased with the urease test grade, chronic gastritis degree, active gastritis, and H. pylori infiltration. Presence of CagA-positivity is well correlated with a high urease test grade and high anti-H. pylori IgG/IgA levels.

Alkali production in the mouth and its relationship with certain patient's characteristics

Objectives To assess the relationships among alkali production, diet, oral health behaviors, and oral hygiene. Methods Data from 52 subjects including demographics, diet, and oral hygiene scores were analyzed against the level of arginine and urea enzymes in plaque and saliva samples. An oral habit survey was completed that included: use of tobacco (TB), alcohol (AH), sugary drinks (SD), and diet. Alkali production through arginine deiminase (ADS) and urease activities were measured in smooth-surface supragingival dental plaque and un stimulated saliva samples from all subjects. ADS and urease activities were measured by quantification of the ammonia generated from the incubation of plaque or saliva samples. Spearman correlations were used to compute all associations. Results Participants in the lowest SES (Socio-economic status) group had the habit of consuming sugary drinks the most and had the highest rate of tobacco use. Males consumed significantly more alcohol than females. No significant relationship was found between age or gender and alkali production. Higher rates of sugary drink consumption and tobacco use were significantly related to lower alkali production. Conclusion The study showed a relationship between alkali production and oral hygiene, diet, and certain oral health behaviors. Poor oral hygiene was significantly associated with age, lower SES, tobacco use, and alcohol, and sugary drinks consumption. Clinical relevance Certain oral health behaviors have an impact on oral hygiene and on alkali production; it is important to address these factors with patients as a strategy for caries control. .

Hemolytic and urease activities in vibrios isolated from fresh and frozen oysters

INTRODUCTION: The present study aimed to survey the Vibrio microbiota of oysters (Crassostrea rhizophorae) obtained from restaurants in Fortaleza, State of Ceará, Brazil, and to identify virulence factors. METHODS: The isolated vibrios were submitted to biochemical identification and were tested for hemolytic and urease activities. RESULTS: The isolated strains belonged to 13 species, with predominance of Vibrio mimicus. Of the strain isolates only from fresh samples, 20.5% and 2.8% showed hemolytic and urease activities, respectively. CONCLUSIONS: The findings support the little-publicized claim that Vibrio species other than V. parahaemolyticus and V. vulnificus can represent a health risk to public health.

Impact of transgenic cotton varieties on activity of enzymes in their rhizosphere.

The impact of five Bacillus thuringiensis (Bt) cotton varieties and their respective isogenic non-Bt(NBt) isolines (ANKUR-2534, MECH-6304, RCH-317, ANKUR-651 and MECH-6301) was assessed on the key soil enzymes i.e., dehydrogenase, alkaline phosphatase and urease in their rhizosphere at four growth stages of the crop, namely vegetative, flowering, bolling and harvesting. These varieties were grown on farmer’s field in villages 22 miles and 24 miles of Ganganagar District of Rajasthan State in India. Results showed that dehydrogenase, alkaline phosphatase and urease activities were higher in rhizosphere of Bt isolines as compared to NBt isolines of all the varieties. Except phosphatase, differences in dehydrogenase and urease activities in rhizosphere of Bt and NBt isolines of all five varieties were significant (P<0.05). Maximum enhancement in the three enzymes activities was observed in MECH-6304 Bt isoline rhizosphere. Maximum and minimum activities of dehydrogenase and urease were observed in MECH-6304 and RCH-317 Bt isolines, respectively, whereas phosphatase activity was maximum and minimum in MECH-6304 and ANKUR-651 Bt isolines, respectively. Maximum dehydrogenase and urease activities were observed at boll formation and minimum at flowering and harvesting stage, respectively, while maximum phosphatase activity was observed at vegetative stage and minimum at harvesting stage. In conclusion, all the studied Bt isolines of cotton varieties showed no adverse effect on dehydrogenase, alkaline phosphatase and urease activities in the rhizosphere.

The Usefulness of the Regular Arrangement of Collecting Venules Pattern for the Determination of Helicobacter pylori Infection / 대한소화기학회지

BACKGROUND/AIMS: In the Helicobacter pylori (H. Pylori)-negative normal stomach, collecting venules are visible over all the gastric body as numerous minute points evaluated with standard endoscopy. This finding was termed regular arrangement of collecting venules (RAC), and its absence suggests H. Pylori gastritis. The aim of this study was to evaluate the correlation between the RAC and rapid urease test. METHODS: Two hundred sixty three consecutive adults undergoing upper digestive endoscopy and rapid urease test were included. The lesser curvature of the lower corpus was evaluated for the RAC pattern using a standard endoscope and different hemoglobin index. Two biopsies from the lesser curvature of the antrum and the greater curvature of the body were collected for rapid urease test. RESULTS: H. Pylori were detected in 51.3% (135/263) patients. Of the 57 patients with H. Pylori-negative normal stomachs 53 patients (93%) had RAC. As a determinant of the normal stomach without H. Pylori infection, the presence of RAC had 41.4% sensitivity, 97.0% specificity, 93.0% positive predictive value and 63.6% negative predictive value. CONCLUSIONS: RAC-positive finding by standard endoscopy showed high positive predictive value and specificity of H. Pylori-negative normal stomach. RAC-positive finding by standard endoscopy could be an useful finding to predict H. Pylori negativity.

Helicobacter pylori Urease Activity is Influenced by Ferric Uptake Regulator

PURPOSE: The role of the Ferric Uptake Regulator (FUR) in the acid resistance of Helicobacter pylori (H. pylori) has been thought to be independent of urease. However, we demonstrated in this study that Fur influences urease activity. MATERIALS AND METHODS: A fur knockout mutant of H. pylori was constructed by replacing the Fur gene with a kanamycin resistant marker gene. The wild-type H. pylori and fur mutant were compared for survival. The integrity of the inner membrane of the bacteria was evaluated by confocal microscopy using membrane-permeant and -impermeant fluorescent DNA probes. Urease activity of intact H. pylori was measured between pH 3 and 8. Real time PCR of both strains was performed for urease genes including ureI, ureE, ureF, ureG, and ureH. RESULTS: The fur deletion affected the survival of H. pylori at pH 4. The urease activity curve of the intact fur mutant showed the same shape as the wild-type but was 3-fold lower than the wild-type at a pH of less than 5. Real time PCR revealed that the expression of all genes was consistently down-regulated in the fur mutant. CONCLUSION: The results of this study showed that fur appears to be involved in acid resistant H. pylori urease activity.

Behaviour of enzymatic activities and root elongation in Argiudoll soils from the Argentine Humid Pampa treated with biosolids / Comportamiento de actividades enzimáticas y elongación de raíces en suelos Argiudoles de la Pampa Húmeda, Argentina, tratados con biosólidos

The incorporation of biosolids to soil is a strategy aiming at the re-location of these materials in the environment with a useful end: soil fertilization. In this work, the response of two Argiudoll soils (one with more than 100 years of agriculture and the other, a virgin one) to biosolid incorporation was studied under laboratory conditions. To measure this response, soil enzymatic biodescriptors, such as dehydrogenase and urease activities, and tests related to plant physiology (the root elongation test) were employed. The addition of the biosolid to both soils had a stimulating effect though different on each soil according to the added dose. Adjustment of the regression line for dehydrogenase activity with root elongation was positive and statistically significant (p<0.001). Results suggest that biodescriptors employed were suitable for studying the impact of amended biosolids on different soils.

La incorporación de biosólidos al suelo es una estrategia que tiene como objetivo la reubicación de estos materiales en el ambiente con un fin útil, como es la fertilización del suelo. En este trabajo se estudió, en condiciones controladas de laboratorio, la respuesta de dos suelos Argiudoles (uno con más de 100 años de agricultura y otro virgen) frente a la perturbación físico-química y biótica que genera la incorporación de un biosólido. Para medir esta respuesta se emplearon dos biodescriptores edáficos (las actividades deshidrogenasa y ureasa) y un tercero referido a la fisiología vegetal, la prueba de elongación de raíces. La incorporación del biosólido en ambos suelos, en general no deprimió el funcionamiento de las actividades enzimáticas estudiadas; contrariamente, según la dosis aportada tuvo un efecto estimulante, aunque diferente, entre ambos suelos. El ajuste de la recta de regresión de la actividad deshidrogenasa con la elongación de las plántulas fue positivo y altamente significativo, lo que indica la complementaridad de ambos descriptores. Los resultados obtenidos sugieren que los biodescriptores empleados resultaron aptos para estudiar el impacto que produce la incorporación de biosólidos a suelos agrícolas.

Lack of association between Helicobacter pylori and laryngeal carcinoma.

OBJECTIVE: To survey the role of Helicobacter pylori at the tissue level as a cause of squamous cell carcinoma of the larynx. DESIGN: A case-control study. SETTING: In an Otolaryngology Ward at an academic university. SUBJECTS: Patients with laryngeal cancer as cases and patients with benign laryngeal lesion as controls. MAIN OUTCOME MEASURE: In all subjects, specimens of laryngeal tissue were examined by rapid urease test while histopathologic examination was achieved to detect H. Pylori. RESULTS: Totally, 44 patients (42 men and 2 women) with squamous cell carcinoma of larynx and 30 patients (24 men and 6 women) with benign laryngeal lesions (polyp, nodule, granuloma) were studied, none of which were infected with the bacterium. CONCLUSION: Our results did not show H. Pylori infection among patients with laryngeal cancer (SCC) or benign laryngeal lesions. .

Sensitivity and specificity of an in-house rapid urease test for detecting Helicobacter pylori infection on gastric biopsy.

We developed an in-house rapid urease test (iRUT) and evaluated the efficacy and the agreement of the iRUT and the cRUT compared with culture and histology for the detection of H. pylori infection. Five iRUT media were tested with H. pylori isolates and other bacteria. The most suitable iRUT medium was further evaluated for detection of H. pylori infection. Gastric biopsies from 120 patients were diagnosed by culture, iRUT, cRUT and histology. The results of the iRUT and cRUT were read at 30 minutes, 1 hour and up to 24 hours. A true positive result was either the culture or both the RUT (cRUT or iRUT) and the histological examination being positive. The sensitivity and specificity of the iRUT result at 30 minutes, 1 hour and up to 24 hours were 77.1% and 100%, 77.6% and 100%, and 94.1% and 94.2%, respectively. Values for the same parameters of cRUT were 87.5% and 100%, 89.8% and 100%, and 100% and 94.2%, respectively. The agreement between the iRUT and cRUT was very good (kappa values > or = 0.82). Our results indicate that the iRUT is a-sensitive, specific and cost effective test. It can be appropriately applied for detecting H. pylori infection in gastric biopsy specimens.

Helicobacter pylori infection at a university hospital in Saudi Arabia: prevalence, comparison of diagnostic modalities and endoscopic findings.

The presence of Helicobacter pylori (H. pylori) was examined in 491 sequential patients, complaining mainly of epigastric pain, by three biopsy-based methods (rapid urease, histology, and culture), and by a serological test, enzyme immunosorbent assay, (ELISA). H. pylori was detected in 341 (70%) of 491 patients examined by histology, 287 (59%) by rapid urease test, whereas 385 (78%) were seropositive for H. pylori immunoglobulins by ELISA. None of the test methods used was independently sufficient to make an etiologic diagnosis of H. pylori infection. The endoscopic findings revealed that 315 (69%) of 456 patients with non-ulcer dyspepsia, 17 (74%) of 23 patients with duodenal ulcer, 7 (78%) of 9 patients with gastric ulcer, and 2 (67%) of 3 patients with gastric cancer were H. pylori positive. No statistically significant correlation was found between the endoscopic and the histopathological findings. A significant correlation was found between H. pylori infection and the histopathological gradings of gastritis (P < 0.001).

Cloning of the gene encoding urease subunit A in Helicobacter pylori / 华中科技大学学报（医学）（英德文版）

The gene encoding urease subunit A (ureA) of Helicobacter pylori (H. pylori) was cloned from H. pylori isolate by polymerase chain reaction (PCR). Sterile distilled water instead of DNA served as negative control. The nucleotide sequence of the amplified product was determined. Homologous analysis of the ureA against that reported by Clayton CL and the GenBank and SwissProt databases were performed with the BLAST program at the Genome Net through the Internet. 0.8 kb PCR product was amplified from all H. pylori clinical isolators. The nucleotide sequence of the ureA was determined. The nucleotide sequence of the ureA began with ATG as the initiation codon and terminated in TAA as stop codon. The coding regions had a 44% G + C content. The DNA sequence was 98% homologous to that reported by Clayton CL (688 out of 702 residues were identical). The derived amino-acid sequences of the ureA were 99% homologous to that reported by Clayton CL (232 out of 234 residues were identical). The nucleotide sequence and the predicted protein showed significant homology to ureA of H. pylori in the NCBI Entrez database.

Evaluación de un test líquido de UREASA ( LUT ) para la detección de Helicobacter pylori / Evaluation of a liquid urease test ( LUT ) for detection of Helicobacter pylori

The aim of our study was to develop a rapid diagnostic urease test to demonstrate the presence of Helicobacter pylori in the Endoscopy room. MATERIALS AND METHODS: 200 consecutive patients referred to gastroscopy for different indications, were included in this study. One antral biopsy sample was obtained to be immersed in our test. The same sample was used for histological evaluation, considered to be the gold standard method for diagnose of Helicobacter pylori infection. RESULTS: 135 patients (67.5%) were found positives and 65 patients (32.5%) were negatives in our test. 128 patients (64%) showed Helicobacter pylori on histological examination. Our test showed a sensitivity of 91%, specificity of 88.1%, and positive and negative predictive values of 95% and 80% respectively. A remarkable correlation between density of Helicobacter pylori and reading time was also observed, where a high density of the bacteria reduced the reaction time in this liquid test. Furthermore, an overall accuracy of 90% was shown, which is comparable with other available commercial tests. CONCLUSION: LUT is easy to handle, cost effective and fast, with a high positive predictive value.

Prevalence and Clinical Characterization of Gastric Helicobacter Species Infection of Dogs and Cats in Korea

This study was carried out to evaluate the prevalence and clinical characterizations of gastric Helicobacter spp. infection of dogs and cats in Korea. The prevalence of Helicobacter spp. infection of dogs and cats determined by urease test was 78.4% and 64%, respectively, although Helicobacter genus-specific PCR assay showed that it was 82.3% and 84%. Urease mapping results based on urease test showed that total positive rate of tested tissues from clinically abnormal dogs was significantly higher than that from clinically normal dogs (p=0.0018; Odds ratio = 6.118; 95% Confidence Interval = 1.96~19.103). These findings were consistent with the results of Helicobacter genus-specific PCR assay which showed that positive rate of the fundus (100%) and the antrum (100%) of clinically abnormal dogs was significantly higher than that of same gastric regions of clinically normal dogs (77.5 and 67.5% respectively). In comparison of gastric regions between clinically normal dogs and abnormal dogs, positive rate of urease test for the fundus (100%) and body (90.9%) in clinically abnormal dogs was significantly higher than that of abnormal dogs (72.5% and 57.5% respectively; p<0.05). The results of urease mapping in dogs and cats also indicated that Helicobacter colonization in the fundus was more dense compared with the density in the body and antrum. In Helicobacter species-specific PCR assay for dogs, 32 of 42 fundic tissues (76.2%) were positive for H. heilmannii and two (4.8%) were positive for H. felis. In cats, 18 of 21 fundic tissues (85.7%) were positive for H. heilmannii and 2 (9.5%) were positive for H. felis. Gastritis scores of fundic tissues from clinically abnormal infected dogs were similar to that from noninfected dogs and evidence of upregulation of IL-1beta, IL-8, and TNF-alpha mRNA was not detected in gastric fundic tissues from clinically abnormal infected dogs. This study suggested that Helicobacter spp. infection in domestic dogs including private owned pet dogs and cats is highly prevalent usually with no clinical sign but high density of colonization can be related to gastrointestinal signs

Evaluación de una prueba de ureasa rápida para la detección de Helicobacter pylori / Evaluation of a fast urease test for the detection of Helicobacter pylori

La mucosa gástrica coloniza el Helicobacter pylori siendo la adaptación al medio relacionada con su alta actividad de la ureasa. Este enzima hidroliza la urea gástrica neutralizando el medio ácido que rodea la bacteria. Sobre la base de esta reacción se desarrollaron numerosos test diagnósticos usando una solución de urea (habitualmente 6 por ciento) con un indicador de pH (Rojo Fenol 0.05 por ciento), pero el contenido de color es tan leve que a veces no se detecta. Por esta razón, se propone una modificación usando una mezcla de indicadores de pH (Rojo Fenol 0.05 por ciento y 0.002 de azul de Bromotimol) que induce un control de calor del verde suave al púrpura fuerte. También se usa solamente azul de bromotimol. El uso de este indicador muestra los valores más altos de sensibilidad y especificidad (69 y 56 por ciento respectivamente). La mezcla de ambos 58.8 y 66.6 por ciento y el azul de bromotimol 46 y 71 por ciento. La eficacia usando Rojo Fenol o la mezcla con bromotimol es de 64.2 y 62.2 por ciento respectivamente; sin embargo, la mezcla de estos indicadores induce un cambio de calor más facilmente detectable.

Helicobacter pylori: estudio comparativo de diferentes técnicas diagnósticas / Helicobacter pylori: comparative study of different diagnostic techniques

Con el objetivo de comparar diferentes técnicas de diagnóstico de Helicobacter pylori, enfrentamos el cultivo bacteriológico con técnicas menos laboriosas, de fácil manipulación, rápidas y menos onerosas, como el test rápido de la ureasa, el frotis con coloración, el estudio histopatológico y la determinación de anticuerpos anti Helicobacter pylori de clase IgG. Se estudiaron en forma prospectiva 43 pacientes de consulta hospitalaria, con sintomatología gastroduodenal. Con signos endoscópicos de inflamación y/o úlcera gastroduodenal. Se tomaron biopsias de Antro, Fundus gástrico y Bulbo duodenal, procesadas de la siguiente manera: a los 43 pacientes, para cada localización se realizó estudio microbiológico (frotis con coloración de Gram y Azul de Metileno, y cultivo en medio selectivo) y estudio histopatológico con cortes coloreados con Hematoxilina - Eosina. En la muestra antral de 37 pacientes se realizó) el test rápido de la ureasa (Clotest, Lab. Delta Westlen). El estudio inmunológico de búsqueda de anticuerpos de clase IgG mediante una técnica inmunoenzimática se hizo en 40 pacientes. Obteniéndose una sensibilidad (S) y una especificidad (E) para el frotis con coloración de 100 por ciento y 76 por ciento respectivamente. Para la antomía patológica: S = 86 por ciento y E = 61 por ciento, el test de la ureasa S = 100 por ciento y E = 62.5 por ciento, anticuerpos anti Helicobacter S = 100 por ciento y E no calculable. Se tomó el cultivo microbiológico como técnica de referencia basándonos en que el aislamiento del germen y su identificación constituye el criterio de presencia y vitalidad del mismo. Siendo el frotis con coloración, la anatomía patológica y el test rápido de la ureasa técnicas de buena presunción diagnóstica de infección presente, rápidas y de bajo costo para nuestro medio. En cambio el estudio inmunológico es de elección para conocer la prevalencia de la infección dado que la misma es de curso lento y los anticuerpos están presentes por tiempo prolongado en los infectados incluso después del tratamiento.