Comparative evaluation of a point-of-care immunochromatographic test SNAP 4Dx with molecular detection tests for vector-borne canine pathogens in Hong Kong

There are no comprehensive studies on the performance of commonly used point-of-care diagnostic enzyme immunoassay for common arthropod-borne canine pathogens. A comparative evaluation of an immunochromatographic test for these infections with a comprehensive polymerase chain reaction (PCR) test panel was performed on 100 pet dogs and 100 stray dogs without obvious clinical symptoms. Of the 162 positive test results from both immunochromatographic test and PCR, there was 85.2% concordance. The 24 discordant results between serology and PCR occurred in tests involving Ehrlichia canis (14) and Anaplasma platys (10), which may be related to the time of infection. No positive cases of borreliosis or rickettsiosis were detected. One important limitation of the immunochromatographic test was its lack of testing for babesiosis and hepatozoonosis. The former is the most prevalent arthropod-borne canine infection in our cohort (41%). Coinfections were found in 19% stray dogs and 6% of pet dogs with both tests (p<0.01). Seventeen and 8 samples from stray and pet dogs, respectively, were initially positive in the PCR test for Ehrlichia. However, on sequencing of the PCR amplicon, 10 from stray and 2 from pet dogs were found to be Wolbachia sequences instead, with 100% nucleotide identity to the 16S rRNA sequence of Wolbachia endosymbiont of Dirofilaria immitis. The presence of Wolbachia DNAemia (6%) correlated well with the molecular test and immunochromatographic antigen test for D. immitis. © Copyright 2011, Mary Ann Liebert, Inc.published_or_final_versio

Diagnosis of Helicobacter pylori infection after gastric surgery for peptic ulcer: Is the rapid urease test useful?

Background: The usefulness of the rapid urease test (RUT) in diagnosing Helicobacter pylori infection after peptic ulcer surgery is unknown. Methods: Patients who had undergone peptic ulcer surgery were offered endoscopic examination if they presented with dyspepsia or gastrointestinal bleeding. Biopsy specimens were taken for RUT and histology from the corpus and the stoma in patients who had undergone partial gastrectomy or from the corpus and the antrum in patients who had undergone vagotomy. Histologic examination using haematoxylin and eosin stain and Warthin-Starry stain were used as the gold standard. Results: Ninety patients were studied (69 had partial gastrectomy and 21 had vagotomy). Forty-three patients (32 in the partial gastrectomy group and 11 in the vagotomy group) were positive for H. pylori by histology. The respective sensitivity of RUT was 59% (stoma) and 75% (corpus) in the partial gastrectomy group (P= 0.36) and 55% (antrum) and 73% (corpus) in the vagotomy group (P= 0.51). Conclusions: RUT is not sensitive for detecting H. pylori after acid reduction surgery.link_to_subscribed_fulltex

Ulcer recurrence after gastric surgery: Is Helicobacter pylori the culprit?

Objectives: Helicobacter pylori is the most important cause of recurrent peptic ulcer disease. However, its role in ulcer recurrence after peptic ulcer surgery is unclear. We aimed at studying the prevalence and distribution of H. pylori in patients who had undergone peptic ulcer surgery, and any association between H. pylori infection and ulcer recurrence in these patients. Methods: Patients with previous vagotomy or partial gastrectomy presenting with dyspepsia or ulcer bleeding were recruited. Ulcer recurrence was documented by endoscopy. Biopsy specimens were taken from the gastric remnant and gastroenteric anastomosis in patients with previous partial gastrectomy, or from the antrum and corpus in vagotomized patients. H. pylori infection was detected by either a positive rapid urease test or the presence of the bacteria on histology. Results: Ninety-three patients were studied; 73 patients (78%) had partial gastrectomy and 20 (22%) had vagotomy with drainage. H. pylori infection was documented in 36 patients (49%) in the gastrectomy group and in 13 (65%) in the vagotomy group. Thirty-six patients in the gastrectomy group had recurrent ulcers and 15 (42%) of them had H. pylori infection. Twelve patients in the vagotomy group had recurrent ulcers and eight (67%) of them were H. pylori positive. The prevalence of H. pylori infection did not differ between patients with or without ulcer recurrence. Conclusion: H. pylori infection cannot account for ulcer recurrence after peptic ulcer surgery.link_to_subscribed_fulltex

Correlation between Helicobacter pylori infection, gastric inflammation and serum homocysteine concentration

Background. Epidemiological studies have suggested a link between chronic Helicobacter pylori infection and ischemic heart disease but the underlying mechanism remains elusive. We hypothesized that H. pylori-associated chronic gastritis causes impairment of absorption of vitamin cofactors that are essential in the metabolism of homocysteine and results in hyperhomocysteinemia. Materials and Methods. Forty-nine dyspeptic patients were studied. H. pylori infection was defined by rapid urease test and histology. Fasting serum homocysteine level, which was measured by a validated commercial fluorescence polarization immunoassay, was correlated with H. pylori infection statuses and gastric histology. H. pylori-infected patients were followed up for 24 weeks post eradication for changes in serum homocysteine concentration. Results. Univariate analyses showed that serum homocysteine level correlated with increasing age (p < .001), male sex (p = .003) and smoking habit (p = .025). There was no significant difference in serum homocysteine levels between H. pylori infected and uninfected subjects (median 10.5 vs. 10.2 μmol/l). After successful eradication of the bacterium, there was no significant reduction in homocysteine level. Moreover, there was no correlation between homocysteine level and gastric histology including H. pylori density, activity and inflammation scores, presence of atrophy or intestinal metaplasia. Conclusions. The postulated link between H. pylori infection and ischemic heart disease, if it actually exists, is unlikely to be mediated through hyperhomocysteinemia.link_to_subscribed_fulltex

Prevalence and distribution of Helicobacter pylori in gastroesophageal reflux disease: A study from the east

OBJECTIVES: The relationship between Helicobacter pylori infection and gastroesophageal reflux (H. pylori) disease (GERD) is controversial. In Asian populations, the prevalence of H. pylori infection is high and GERD is relatively uncommon. The aim of this study was 1) to test the hypothesis that H. pylori protects the esophagus against GERD, and 2) to study the pattern of H. pylori colonization and gastritis in GERD. METHODS: We conducted a prospective case-control study in which patients with GERD and asymptomatic controls were compared for the prevalence of H. pylori infection. Diagnosis of GERD was based on symptoms of heartburn that improved with acid- suppressive therapy and/or endoscopic evidence of erosive esophagitis. H. pylori status was determined by serology and, when endoscopy was indicated, was confirmed by rapid urease test and histology. Gastric biopsies were examined under hematoxylin and eosin and Giemsa stains. Density of H. pylori colonization and activity of gastritis at different parts of stomach were graded and compared according to Updated Sydney system. RESULTS: A total of 106 patients with GERD and 120 age-and sex-matched, asymptomatic controls were enrolled. The prevalence of H. pylori infection was significantly lower in GERD patients (31%) compared with controls (61%, p < 0.001, odds ratio 0.229, 95% confidence interval 0.13-0.41). H. pylori-infected GERD patients showed significantly more severe gastritis in the antrum than in other parts of stomach (mean inflammatory scores: antrum; 3.3 ± 1.63, body; 1.85 ± 1.31; fundus; 1.65 ± 0.58; cardia, 1.65 ± 1.39; p < 0.005). H. pylori colonization was found less commonly and at lower density at the cardia compared with other parts of the stomach. CONCLUSIONS: H. pylori infection protects against the development of GERD, and carditis is unlikely to play an important role.link_to_subscribed_fulltex

A comparison of the acceptance of immunochemical faecal occult blood test and colonoscopy in colorectal cancer screening: A prospective study among Chinese

Background Preferences to choose immunochemical faecal occult blood test (FIT) and colonoscopy as colorectal cancer (CRC) screening modalities among asymptomatic Chinese subjects remain unknown. Aim To evaluate the preference of choosing colonoscopy vs. FIT among CRC screening participants. Methods From a community-based CRC screening programme for asymptomatic Hong Kong Chinese aged 50-70 years, participants attended standardized educational sessions and chose the options of annual FIT for 5 years or direct colonoscopy once. Factors associated with choosing colonoscopy were evaluated by multivariate regression analysis. Results Among 3430 participants [mean age 56.8 years (s.d. 5.0); female 55.1%, male 44.9%], 51.3% chose colonoscopy and 48.7% chose FIT. Older participants (65-70 years) were less likely to choose colonoscopy [adjusted odds ratio (aOR) 0.731, P = 0.041]. Subjects who chose colonoscopy were those disagreed screening would lead to discomfort (aOR 1.356, P < 0.001), had relatives or friends who had CRC (first degree relatives aOR 1.679, P < 0.001; second degree relatives aOR 1.304, P = 0.019; friends or others aOR 1.252, P = 0.026) and those who self-perceived their health as poor (aOR 1.529, P = 0.025). Conclusions Faecal occult blood test and direct colonoscopy were equally preferable to Chinese. Colonoscopy was preferred among the younger subjects, those with positive family history of CRC and self-perceived poor health status. © 2010 Blackwell Publishing Ltd.link_to_subscribed_fulltex

Is non-Helicobacter pylori, non-NSAID peptic ulcer a common cause of upper GI bleeding? A prospective study of 977 patients

Non-Helicobacter pylori, non-NSAID ulcer is relatively common in Western countries. Whether it is a significant problem in the Orient is unclear. The aim of this study was to investigate the incidence of non-H pylori, non-NSAID ulcers presenting with GI bleeding. A prospective study was done of 1675 consecutive patients presenting with upper GI bleeding over a period of 12 months. Upper endoscopy was performed with biopsy specimens taken from the antrum and body of the stomach for a biopsy urease test (BUT) and histology for detection of H pylori. Exposure to nonsteroidal anti-inflammatory drugs (NSAID) or aspirin within 4 weeks of hospitalization was carefully scrutinized. A 6-week course of treatment with an H2-receptor antagonist was prescribed for patients who did not use an NSAID and had a negative BUT result. Follow-up endoscopy was performed to confirm H pylori status with a BUT and histology. Positive histology at either initial or follow-up endoscopy was used as the standard for diagnosing H pylori infection. Among 977 patients who were found to have ulcer bleeding, 434 (44%) had exposure to aspirin or an NSAID. Of the 543 non-NSAID users, 431 (79.4%) had a positive BUT and 112 (20.6%) were BUT negative on initial endoscopy. Eighty-nine of 112 patients who were NSAID negative, BUT negative returned for follow-up endoscopy. Forty-nine of 89 (55.1%) were found to have a positive BUT and positive histology at follow-up endoscopy. Only 40 of 977 (4.1%) patients admitted with ulcer bleeding were confirmed to have non-H pylori, non-NSAID ulcers. Non-H pylori, non-NSAID bleeding ulcer is uncommon. A negative BUT is unreliable for exclusion of H pylori infection during the acute phase of ulcer bleeding.link_to_subscribed_fulltex

Brittle tail syndrome is an emerging infection in horses caused by a keratinolytic fungus Equicapillimyces hongkongensis gen. nov., sp. nov

The newly described brittle tail syndrome causes weakening and breakage of the tail hair of horses. Extensive mycological and molecular studies showed that a novel fungus Equicapillimyces hongkongensis gen. nov., sp. nov. is the most likely cause of this syndrome. It is a septate branching hyaline mould which grows optimally at 30 °C, requires nicotinic acid but is inhibited by cycloheximide, and specifically infects horse hair. Hyphae fill the core of infected hair shafts with short-necked structures resembling ascomata containing banana-shaped septate ascospore-like structures perforating the hair cortex from within. Compared to asymptomatic horses (n= 31), horses with clinical signs of the syndrome (n= 22) are significantly more likely to have positive E. hongkongensis gen. nov., sp. nov. smear (6.5% vs. 100%), culture (6.5% vs. 72.7%), and PCR (32.3% vs. 100%, P< 0.001 for all). No other potential pathogens were found on bacteriological and mycological culture or PCR (for Trichophyton, Microsporum and Epidermophyton). Genotyping of pure E. hongkongensis gen. nov., sp. nov. isolates and their corresponding direct specimens by PCR and sequencing of the 18S rRNA, ITS1-5.8S-ITS2, 28S rRNA, beta-actin, beta-tubulin, and elongation factor 1 alpha showed that they are all identical but unique, and related distantly to fungi mostly in the class Sordariomycetes and the family Ophiostomataceae. Its geographical distribution, environmental or animal reservoirs are still unknown. Besides the ugly appearance of infected horse tails, this fungus may emerge as another equine pathogen if it affects the skin and hoof of horses. © 2011 Elsevier B.V.link_to_subscribed_fulltex