This study compared diagnostic methods for identifying Blastocystis in stool samples, and evaluated the frequency of detection of Blastocystis in patients with irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD).
Results and Discussion
From a set of 105 stool specimens submitted for routine parasitological analysis, 30 were identified as positive for Blastocystis by the culture method. From that group of 30 positives, Lugol's stain, trichrome staining, and an immunofluorescence assay identified 11, 15, and 26 samples as positive respectively. Using culture as a standard, the sensitivity of Lugol's stain was 36.7%, trichrome staining was 50%, and the IFA stain was 86.7%. The specificity of Lugol's stain was 91%, trichrome staining was 100%, and the IFA stain was 97.3%. In the group of 27 IBS and IBD patients, using all methods combined, we detected Blastocystis in 67% (18/27) of the patients. Blastocystis was detected in 33% (2/6) of IBD patients and 76% (16/21) of IBS patients. For comparison, trichrome staining alone, the method most frequently used in many countries, would have only identified Blastocystis infection in 29% (6/21) of the IBS patients. No parasitic co-infections were identified in the IBS/IBD patients. Most Blastocystis-positive IBS/IBD patients were over 36 with an average length of illness of 4.9 years.
Most IBS patients in this study were infected with Blastocystis. IFA staining may be a useful alternative to stool culture, especially if stool specimens have been chemically preserved.
To determine the prevalence and seasonal variation, and to assess the clinical manifestations and treatment of blastocystosis in Libyan patients.
Three thousand six hundred and forty five stool samples were screened for Blastocystis hominis using normal saline and iodine solution preparations. The clinical features of 108 patients were described, in whom B. hominis was the only parasite isolated. Fifty symptomatic patients were treated with 1500 mg metronidazole daily for 7 days and their stools were re-investigated for B. hominis.
B. hominis was found in 969 (26.58 %) of 3645 stool specimens examined. The infection of B. hominis was significantly more (p < 0.05) in summer than in winter over a three year period. In a prospective study of 108 patients, the most common symptoms with stools positive only for B. hominis were diarrhoea (84.94 %), abdominal pain (66.66 %), flatulence (17.20 %) and vomiting (16.12 %). High concentration of B. hominis cells were found more in symptomatic patients than asymptomatic ones (9.20 cells per 40 X field versus 4.06 respectively) with statistically significant differences (p < 0.001). Patients with B. hominis responded to metronidazole and were fully cured after 7 days.
The occurrence of B. hominis infections in outpatients are probably related to weather conditions, with the suggestion that the hot, dry weather of the Sebha region favors the development and transmission of this organism. B. hominis infections might have a role in some pathological conditions, resulting in gastrointestinal symptoms.
Blastocystis; Seasonal variation; Culture; Diarrhoea
One hundred and fifteen patients with symptoms suggestive of irritable bowel syndrome (IBS) according to Rome III criteria and 209 patients with gastrointestinal symptoms different from IBS (control) were identified through medical records from the Gastroenterology Clinic of the "Dr. Manuel Gea Gonzalez General Hospital" from January 2008 to March 2010. No statistical differences in IBS data as compared with control groups were observed except in bloating, that was more frequent in the IBS group (P = 0.043). Although the pathogenicity of specific intestinal protozoa could not be demonstrated due to lack of association with the development of gastrointestinal symptoms, Blastocystis spp, in the IBS group, exhibited a trend of association to diarrhoea (odds ratio = 2.73, 95% confidence interval = 0.84-8.80, P = 0.053), while having any parasite and diarrhoea was significant (odds ratio = 3.38, 95% confidence interval = 1.33-8.57, P = 0.008). The association between Blastocystis and diarrhoea in IBS patients although not conclusive is an interesting finding; nonetheless more extensive case-controlled studies are required to clearly define the role of some "non-pathogenic" parasites in intestinal disease and IBS.
Blastocystis is a prevalent enteric protozoan that infects a variety of vertebrates. Infection with Blastocystis in humans has been associated with abdominal pain, diarrhea, constipation, fatigue, skin rash, and other symptoms. Researchers using different methods and examining different patient groups have reported asymptomatic infection, acute symptomatic infection, and chronic symptomatic infection. The variation in accounts has lead to disagreements concerning the role of Blastocystis in human disease, and the importance of treating it. A better understanding of the number of species of Blastocystis that can infect humans, along with realization of the limitations of the existing clinical laboratory diagnostic techniques may account for much of the disagreement. The possibility that disagreement was caused by the emergence of particular pathogenic variants of Blastocystis is discussed, along with the potential role of Blastocystis infection in irritable bowel syndrome (IBS). Findings are discussed concerning the role of protease-activated receptor-2 in enteric disease which may account for the presence of abdominal pain and diffuse symptoms in Blastocystis infection, even in the absence of fever and endoscopic findings. The availability of better diagnostic techniques and treatments for Blastocystis infection may be of value in understanding chronic gastrointestinal illness of unknown etiology.
Blastocystis sp. is one of the most common intestinal protozoa in humans. Unlike other intestinal parasitic infections such as giardiasis and cryptosporidiosis, the epidemiology of blastocystosis in children who live in crowded settings such as day-care centers and orphanages has been rarely explored.
A retrospective cohort study was conducted to evaluate incidence and risk factors of Blastocystis infection in an orphanage every two consecutive months during April 2003 to April 2004, in Bangkok, Thailand. Blastocystis sp. was identified using direct simple smear, and in vitro cultivation in Jones' medium.
The incidence rate was 1.8/100 person-months and the independent risk factors associated with Blastocystis infection were age, nutritional status and orphans living in the room where their childcare workers were infected.
Person-to-person transmission was most likely to occur either from orphans to childcare workers or from childcare workers to orphans living in the same room. Universal precautions such as regular hand washing and careful handling of fecally contaminated materials are indicated.
Blastocystis anaerobic parasites are widespread worldwide in the digestive tract of many animal species, including humans. Epidemiological Blastocystis studies are often limited by the poor sensitivity of standard parasitological assays for its detection. This report presents a highly sensitive real-time quantitative PCR (qPCR) assay developed to detect Blastocystis parasites in stool samples. The assay targets a partial sequence of the Blastocystis small ribosomal subunit (SSU) rRNA gene, allowing subtyping (ST) of Blastocystis isolates by direct sequencing of qPCR products. This qPCR method was assessed in a prospective study of 186 patients belonging to two cohorts—a group of 94 immunocompromised patients presenting hematological malignancies and a control group of 92 nonimmunocompromised patients. Direct-light microscopy and xenic in vitro stool culture analysis showed only 29% and 52% sensitivity, respectively, compared to our qPCR assay. Of the 27 (14.5%) Blastocystis-positive patients, 8 (4%) experienced digestive symptoms. No correlation was found between symptomatic patients and immune status, parasite load, or parasite subtypes, although subtyping of all isolates revealed a high (63.0%) prevalence of ST4. Two unexpected avian subtypes were found, i.e., ST6 and ST7, which are frequently isolated in Asia but rarely present in Western countries. In conclusion, this qPCR proved by far the most sensitive of the tested methods and allowed subtype determination by direct sequencing of qPCR products. New diagnostic tools such as the qPCR are essential for evaluating the clinical relevance of Blastocystis subtypes and their role in acute or chronic digestive disorders.
Blastocystis is an enteric protozoan purportedly associated with numerous clinical cases of diarrhea, flatulence, vomiting, and other gastrointestinal symptoms. Despite new knowledge of Blastocystis cell biology, genetic diversity, and epidemiology, its pathogenic potential remains controversial. Numerous clinical and epidemiological studies either implicate or exonerate the parasite as a cause of intestinal disease. Therefore, the aim of this study was to investigate the pathogenic potential of Blastocystis by studying the interactions of Blastocystis ratti WR1, an isolate of zoonotic potential, with a nontransformed rat intestinal epithelial cell line, IEC-6. Here, we report that B. ratti WR1 induces apoptosis in IEC-6 cells in a contact-independent manner. Furthermore, we found that B. ratti WR1 rearranges F-actin distribution, decreases transepithelial resistance, and increases epithelial permeability in IEC-6 cell monolayers. In addition, we found that the effects of B. ratti on transepithelial electrical resistance and epithelial permeability were significantly abrogated by treatment with metronidazole, an antiprotozoal drug. Our results suggest for the first time that Blastocystis-induced apoptosis in host cells and altered epithelial barrier function might play an important role in the pathogenesis of Blastocystis infections and that metronidazole has therapeutic potential in alleviating symptoms associated with Blastocystis.
Blastocystis is a ubiquitous enteric protozoan found in the intestinal tracts of humans and a wide range of animals. Evidence accumulated over the last decade suggests association of Blastocystis with gastrointestinal disorders involving diarrhea, abdominal pain, constipation, nausea, and fatigue. Clinical and experimental studies have associated Blastocystis with intestinal inflammation, and it has been shown that Blastocystis has potential to modulate the host immune response. Blastocystis is also reported to be an opportunistic pathogen in immunosuppressed patients, especially those suffering from AIDS. However, nothing is known about the parasitic virulence factors and early events following host-parasite interactions. In the present study, we investigated the molecular mechanism by which Blastocystis activates interleukin-8 (IL-8) gene expression in human colonic epithelial T84 cells. We demonstrate for the first time that cysteine proteases of Blastocystis ratti WR1, a zoonotic isolate, can activate IL-8 gene expression in human colonic epithelial cells. Furthermore, we show that NF-κB activation is involved in the production of IL-8. In addition, our findings show that treatment with the antiprotozoal drug metronidazole can avert IL-8 production induced by B. ratti WR1. We also show for the first time that the central vacuole of Blastocystis may function as a reservoir for cysteine proteases. Our findings will contribute to an understanding of the pathobiology of a poorly studied parasite whose public health importance is increasingly recognized.
Blastocystis sp. has a worldwide distribution and is often the most common human intestinal protozoan reported in children and adults in developing countries. The clinical relevance of Blastocystis sp. remains controversial. This study was undertaken to determine the prevalence of Blastocystis infection and its association with gastrointestinal symptoms among outpatients in Sebha city, Libya.
A total of 380 stool samples were collected from outpatients attending the Central Laboratory in Sebha, Libya for routine stool examination. The presence of Blastocystis sp. was screened comparing light microscopy of direct smears against in vitro cultivation. Demographic and socioeconomic information were collected with a standardized questionnaire.
The overall prevalence of Blastocystis infection was 22.1%. The prevalence was significantly higher among patients aged ≥18 years compared to those aged < 18 years (29.4% vs 9.9%; x2 = 19.746; P < 0.001), and in males compared to females (26.4% vs 17.5%; x2 = 4.374; P = 0.036). Univariate analysis showed significant associations between Blastocystis infection and the occupational status (P = 0.017), family size (P = 0.023) and educational level (P = 0.042) of the participants. Multiple logistic regression analysis confirmed that the age of ≥ 18 years (OR = 5.7; 95% CI = 2.21; 9.86) and occupational status (OR = 2.2; 95% CI = 1.02, 4.70) as significant predictors of Blastocystis infection among this population. In those who had only Blastocystis infection but no other gastrointestinal parasitic infections, the prevalence of gastrointestinal symptoms was higher compared to those without Blastocystis infection (35.3% vs 13.2%; x2 = 25.8; P < 0.001). The most common symptoms among these patients were abdominal pain (76.4%), flatulence (41.1%) and diarrhoea (21.5%).
Blastocystis sp. is prevalent and associated with gastrointestinal symptoms among communities in Sebha city, Libya. Age and occupational status were the significant predictors of infection. However, more studies from different areas in Libya are needed in order to delineate the epidemiology and clinical significance of this infection.
Blastocystis; Gastrointestinal symptoms; Sebha; Libya
Because unexplained 'functional symptoms' are a major cause of referral to gastroenterologists, the efficiency of the medical history to lead to a positive diagnosis of irritable bowel syndrome, without resorting to the use of expensive tests, remains a key question. Whilst the six criteria of Manning et al are widely used, data on their validity in discriminating irritable bowel syndrome from healthy controls, irritable bowel syndrome from non-ulcer dyspepsia and especially among irritable bowel syndrome subgroups, are not available. To evaluate this, we studied 361 outpatients who completed a bowel disease questionnaire, which objectively measured Manning's (and other) criteria. The group included 82 patients with irritable bowel syndrome, 33 with non-ulcer dyspepsia, 101 with organic gastrointestinal disease, and 145 healthy controls. Diagnoses were based on a full and independent clinical evaluation, not on responses to the bowel disease questionnaire. Reliability was assessed by a test-retest procedure. All six of the individual Manning criteria were found to be reliable (median kappa = 0.79). Based on a logistic regression analysis of the discriminatory value of Manning's criteria, as the number of positive criteria increased, so did the predicted probability of irritable bowel syndrome. This predictive value was highest in younger patients and in females. The Manning criteria discriminated irritable bowel syndrome from organic gastrointestinal disease and from all non-irritable bowel syndrome gastrointestinal disease with a sensitivity of 58% and 42%, and a specificity of 74% and 85%, respectively. Stools that were often loose and watery provided an additional independent criterion for distinguishing irritable bowel syndrome from non-irritable bowel syndrome. Thus, symptoms can be used to diagnose irritable bowel syndrome positively, but Manning's criteria are not highly sensitive.
Blastocystis, one of the most common parasites colonizing the human intestine, is an extracellular, noninvasive, luminal protozoan with controversial pathogenesis. Blastocystis infections can be asymptomatic or cause intestinal symptoms of vomiting, diarrhea, and abdominal pain. Although chronic infections are frequently reported, Blastocystis infections have also been reported to be self-limiting in immunocompetent patients. Characterizing the host innate response to Blastocystis would lead to a better understanding of the parasite's pathogenesis. Intestinal epithelial cells produce nitric oxide (NO), primarily on the apical side, in order to target luminal pathogens. In this study, we show that NO production by intestinal cells may be a host defense mechanism against Blastocystis. Two clinically relevant isolates of Blastocystis, ST-7 (B) and ST-4 (WR-1), were found to be susceptible to a range of NO donors. ST-7 (B), a metronidazole-resistant isolate, was found to be more sensitive to nitrosative stress. Using the Caco-2 model of human intestinal epithelium, Blastocystis ST-7 (B) but not ST-4 (WR-1) exhibited dose-dependent inhibition of Caco-2 NO production, and this was associated with downregulation of inducible nitric oxide synthase (iNOS). Despite its higher susceptibility to NO, Blastocystis ST-7 (B) may have evolved unique strategies to evade this potential host defense by depressing host NO production. This is the first study to highlight a strain-to-strain variation in the ability of Blastocystis to evade the host antiparasitic NO response.
The absorption of 14C triolein in a standard fat meal was measured in 60 controls and 66 patients with gastrointestinal disorders by 14CO2 breath sampling. A reference range based upon cumulative eight hour values of the controls was independent of height, weight, and sex. The range was of log normal distribution and declined with age (p less than 0.05). Acceptable 'within-day' and 'between-day' reproducibility was found. All patients tested with untreated coeliac disease, pancreatic insufficiency and most with symptomatic small intestinal Crohn's disease had subnormal values. Twenty per cent of those with irritable bowel syndrome had subnormal values. Patients with ulcerative colitis were all normal. The reagents used and the breath samples after collection were stable. In our experience the 14C triolein test is simple, inexpensive, and helpful in the detection of diseases associated with fat malabsorption. It is of value in monitoring the response to treatment of individual patients with coeliac disease.
Blastocystis sp. are among the most commonly observed intestinal parasites in routine clinical parasitology. Blastocystis in humans consists of at least 9 genetic subtypes. Different subtypes of Blastocystis may be associated with differences in pathogenicity and symptomatology.
Advanced microscopy on two samples and sequence-confirmed PCR on a third sample from the same individual were used for Blastocystis diagnosis and subtype analyses on routine clinical samples in a university hospital.
With a combined gold standard of sequence-confirmed PCR and positive advanced microscopy, 107 out of 442 (24.2%) patients were diagnosed with Blastocystis. infection, which is a high frequency of detection in comparison to previous reports from industrialized countries. The sensitivity of microscopy and sequence-confirmed PCR was 99.1% (106/107) and 96.3% (103/107), respectively.
Among 103 typable samples, subtype 3 was most abundant (n = 43, 42%), followed by subtypes 1 and 2 (both n = 23, 22%), subtype 4 (n = 12, 12%), and single samples with subtypes 6 (1%) and subtype 7 (1%). The prevalence of Blastocystis infection was 38% in patients from the Department of Tropical Medicine and 18% in patients from other departments.
A high prevalence of Blastocystis infection was found with both advanced microscopy and sequence-confirmed PCR in our patient population. Most cases were caused by subtypes ST1, ST2, ST3 and ST4. A significantly higher prevalence was found among patients with a history of recent travel to tropical countries.
Blastocystis; Diagnosis; Microscopy; PCR; Molecular epidemiology
Three methods for dispensing nutritional solutions are compared in 48 patients with gastrointestinal diseases on intravenous nutrition during 3582 days. The protocol for intravenous nutrition applied by the nursing team and the solutions used were the same in the three groups. In group A standard bottles were used, while in group B, 31PVC-disposable bags were used--with fat emulsion included (group B1) or with fat excluded (group B2). When fat was excluded from the bags it was infused separately from a bottle. The mixtures were made under laminar flow by the nursing team who applied a strict protocol which included bacteriological testing. The infection rate observed in the bags was 0.046%. The rate of septic complications was not significantly reduced in group B2 or B1 compared with group A; the type of container used was therefore unimportant and the key was the aseptic handling of the intravenous solutions. The rate of mechanical complications, mainly due to catheter obstruction, was higher (p less than 0.001) when fat was included in the bags--that is, in group B1--than in groups B2 and A. For 26 patients a cyclical regime of intermittent feeding was easier to manage when bags were used. In group B, this system replaced the continuous method n 75% of all therapeutic days without adverse effect; it improved compliance and allowed ambulatory treatment. The use of cyclical feeding with separate fat infusions has further reduced the hazards of intravenous nutrition and allowed the development of a programme that can be implemented at home.
In patients with Crohn's disease and ulcerative colitis parenteral nutrition (PN) is indicated when enteral nutrition is not possible or should be avoided for medical reasons. In Crohn's patients PN is indicated when there are signs/symptoms of ileus or subileus in the small intestine, scars or intestinal fistulae. PN requires no specific compounding for chronic inflammatory bowel diseases. In both diseases it should be composed of 55–60% carbohydrates, 25–30% lipids and 10–15% amino acids. PN helps in the correction of malnutrition, particularly the intake of energy, minerals, trace elements, deficiency of calcium, vitamin D, folic acid, vitamin B12, and zinc. Enteral nutrition is clearly superior to PN in severe, acute pancreatitis. An intolerance to enteral nutrition results in an indication for total PN in complications such as pseudocysts, intestinal and pancreatic fistulae, and pancreatic abscesses or pancreatic ascites. If enteral nutrition is not possible, PN is recommended, at the earliest, 5 days after admission to the hospital. TPN should not be routinely administered in mild acute pancreatitis or nil by moth status <7 days, due to high costs and an increased risk of infection. The energy requirements are between 25 and 35 kcal/kg body weight/day. A standard solution including lipids (monitoring triglyceride levels!) can be administered in acute pancreatitis. Glucose (max. 4–5 g/kg body weight/day) and amino acids (about 1.2–1.5 g/kg body weight/day) should be administered and the additional enrichment of TPN with glutamine should be considered in severe, progressive forms of pancreatitis.
inflammatory bowel disease; Crohn's disease; ulcerative colitis; pancreatitis
AIM: To investigate the correlations between self-reported symptoms of irritable bowel syndrome (IBS) and the gastrointestinal (GI) microbiota composition.
METHODS: Fecal samples were collected from a total of 44 subjects diagnosed with IBS. Their symptoms were monitored with a validated inflammatory bowel disease questionnaire adjusted for IBS patients. Thirteen quantitative real-time polymerase chain reaction assays were applied to evaluate the GI microbiota composition. Eubacteria and GI bacterial genera (Bifidobacterium, Lactobacillus and Veillonella), groups (Clostridium coccoides/Eubacterium rectale, Desulfovibrio desulfuricans) and distinct bacterial phylotypes [closest 16S rDNA sequence resemblance to species Bifidobacterium catenulatum, Clostridium cocleatum, Collinsella aerofaciens (C. aerofaciens), Coprococcus eutactus (C. eutactus), Ruminococcus torques and Streptococcus bovis] with a suspected association with IBS were quantified. Correlations between quantities or presence/absence data of selected bacterial groups or phylotypes and various IBS-related symptoms were investigated.
RESULTS: Associations were observed between subjects’ self-reported symptoms and the presence or quantities of certain GI bacteria. A Ruminococcus torques (R. torques)-like (94% similarity in 16S rRNA gene sequence) phylotype was associated with severity of bowel symptoms. Furthermore, among IBS subjects with R. torques 94% detected, the amounts of C. cocleatum 88%, C. aerofaciens-like and C. eutactus 97% phylotypes were significantly reduced. Interesting observations were also made concerning the effect of a subject’s weight on GI microbiota with regard to C. aerofaciens-like phylotype, Bifidobacterium spp. and Lactobacillus spp.
CONCLUSION: Bacteria seemingly affecting the symptom scores are unlikely to be the underlying cause or cure of IBS, but they may serve as biomarkers of the condition.
Irritable bowel syndrome; Self-reported symptoms; Gastrointestinal microbiota; Quantitative real-time polymerase chain reaction
Laser capture microdissection (LCM) is an efficient and precise method for obtaining pure cell populations or specific cells of interest from a given tissue sample. LCM has been applied to animal and human gastroenterology research in analyzing the protein, DNA and RNA from all organs of the gastrointestinal system. There are numerous potential applications for this technology in gastroenterology research including malignancies of the esophagus, stomach, colon, biliary tract and liver. This technology can also be used to study gastrointestinal infections, inflammatory bowel disease, pancreatitis, motility, malabsorption and radiation enteropathy. LCM has multiple advantages when compared to conventional methods of microdissection, and this technology can be exploited to identify precursors to disease, diagnostic biomarkers, and therapeutic interventions.
Laser Microdissection; Laser Capture Microdissection
A total of 19,252 stool specimens from 12,136 patients were examined by direct microscopy and the ethyl acetate-Formalin concentration method during the last 2 years. All liquid specimens and those in which parasite identification was difficult or equivocal were also examined in trichrome-stained preparations. A total of 3,070 intestinal parasites were seen in 2,889 patients. Blastocystis hominis was found in fecal material from 647 patients (17.5%). A total of 132 cases (25.6%) were observed to be in association with other enteric pathogens. B. hominis in large numbers was present as the only parasite or with other commensals in 515 specimens from patients (79.6%). Of these patients, 239 (46.4%) had symptoms, the most common being abdominal pain (87.9%), constipation (32.2%), diarrhea (23.4%), alternating diarrhea and constipation (14.5%), vomiting (12.5%), and fatigue (10.5%). Forty-three (18%) of the patients were treated with metronidazole (0.5 to 1.0 g/day) because of recurrent symptoms and the presence of large numbers of B. hominis cells in repeated stool specimens. After 7 to 10 days of treatment, all patients became asymptomatic with negative stools on follow-up examinations for B. hominis.
Blastocystis is a highly prevalent anaerobic eukaryotic parasite of humans and animals that is associated with various gastrointestinal and extraintestinal disorders. Epidemiological studies have identified different subtypes but no one subtype has been definitively correlated with disease.
Here we report the 18.8 Mb genome sequence of a Blastocystis subtype 7 isolate, which is the smallest stramenopile genome sequenced to date. The genome is highly compact and contains intriguing rearrangements. Comparisons with other available stramenopile genomes (plant pathogenic oomycete and diatom genomes) revealed effector proteins potentially involved in the adaptation to the intestinal environment, which were likely acquired via horizontal gene transfer. Moreover, Blastocystis living in anaerobic conditions harbors mitochondria-like organelles. An incomplete oxidative phosphorylation chain, a partial Krebs cycle, amino acid and fatty acid metabolisms and an iron-sulfur cluster assembly are all predicted to occur in these organelles. Predicted secretory proteins possess putative activities that may alter host physiology, such as proteases, protease-inhibitors, immunophilins and glycosyltransferases. This parasite also possesses the enzymatic machinery to tolerate oxidative bursts resulting from its own metabolism or induced by the host immune system.
This study provides insights into the genome architecture of this unusual stramenopile. It also proposes candidate genes with which to study the physiopathology of this parasite and thus may lead to further investigations into Blastocystis-host interactions.
Children with allergic diseases such as asthma and atopic dermatitis experience increased gastrointestinal symptoms. Further, physiological and histological abnormalities of the gastrointestinal tract in patients with allergic diseases have been reported. It is not certain whether adult patients experience increased gastrointestinal symptoms.
A retrospective, case–control study of 7235 adult (⩾20 years old) primary care patients was conducted. A general practitioner diagnosis of irritable bowel syndrome was used to serve as a marker of lower gastrointestinal symptoms. The prevalence of lower gastrointestinal symptoms was calculated in patients with asthma or allergic rhinitis and compared with that in patients with other chronic diseases (insulin‐dependent diabetes mellitus, osteoarthritis and rheumatoid arthritis) and with the remaining population.
Gastrointestinal symptoms were significantly more common in patients with asthma (9.9%) as compared with patients with chronic diseases (4.9%; odds ratio (OR) 2.13, 95% confidence interval (CI) 1.39 to 2.56; p<0.002) or the remaining non‐asthmatic population (5.5%; OR 1.89, 95% CI 1.39 to 2.56; p<0.001). Gastrointestinal symptoms were also significantly more common in patients with allergic rhinitis (7.9%) as compared with patients with chronic diseases (4.9%; OR 1.66, 95% CI 1.02 to 2.7; p<0.05) and the remaining population (5.5%; OR 1.47, 95% CI 1.04 to 2.1; p<0.02). This phenomenon was independent of age, sex and inhaled asthma therapy in the case of patients with asthma.
Our findings support the hypothesis that lower gastrointestinal symptoms are more common in patients with allergic diseases such as asthma and allergic rhinitis.
Blastocystis is a ubiquitous, globally distributed intestinal protist infecting humans and a wide range of animals. Several studies have shown that Blastocystis is a potentially zoonotic parasite. A 1996 study reported a 70% Blastocystis prevalence in Brisbane pound dogs while another study found that pet dogs/cats of 11 symptomatic Blastocystis infected patients harboured at least one Blastocystis subtype (ST) in common with the patient. These results raised the possibility that dogs might be natural hosts of Blastocystis. In this study, we aimed to investigate this hypothesis by estimating the prevalence of Blastocystis carriage and characterising the diversity of STs in dogs from three different environmental settings and comparing these STs with the range that humans harbour.
Two hundred and forty faecal samples from dogs from three different geographical regions with varying levels of socio-economic development and sanitation, namely i) 80 pet and pound dogs from Brisbane, Australia, ii) 80 semi-domesticated dogs from Dong Village, Cambodia and iii) 80 stray dogs from the densely populated cities of Sikkim, Delhi and Mumbai in India, were screened for Blastocystis using PCR and subtyped based on the “barcode region” of the small subunit ribosomal RNA (SSU rRNA) gene.
The prevalence of Blastocystis in dogs from Brisbane and Cambodia was 2.5% (2/80) and 1.3% (1/80), respectively, in contrast to 24% (19/80) in stray dogs from India. Stray dogs in India carried a diverse range of Blastocystis STs including ST 1, 4, 5 and 6 while the dogs from Brisbane carried only ST1 and one Cambodian dog carried ST2.
The results suggest there is geographical variation in Blastocystis prevalence and STs between dog populations as reported in human studies. In addition, the greater diversity of STs and higher prevalence of Blastocystis in Indian stray dogs compared to pet/pound and community dogs in Australia and Cambodia could reflect close proximity to humans and other animals and exposure to their faeces. It appears that dogs are not natural hosts for Blastocystis but rather are transiently and opportunistically infected with a diversity of STs.
Blastocystis; Dog; Zoonosis; Epidemiology
Blastocystis is a highly controversial protozoan parasite. It has been variably regarded as a commensal and pathogen. Scientists have for decades wondered whether it is truly an enteropathogen and if it is observed in symptomatic patients whether treatment is required because patient recovery and improvement has been noted even without any treatment. Though associated with self-limiting infection, treatment is warranted in many patients due to persistence of symptoms. This particularly holds true for children and adults who are immuno compromised. Several drugs have been used to treat Blastocystis but each one of them has produced widely variable rates of clinical cure and eradication of the parasite from the feces. Based on the studies carried out in vitro and clinical responses obtained in patients, metronidazole appears to be the most effective drug for Blastocystis infection. However, the therapy is complicated due to different dosages and regimens adopted and the unresponsiveness to treatment observed in several sections of the population studied. Recently, the finding of different subsets of Blastocystis exhibiting resistance to metronidazole and associated with variable degrees of symptoms has underscored the importance of typing the subsets of the parasite in order to foretell the clinical response and the need to treat. Till date, the mode of action of the drugs used and the mechanism of resistance is not entirely known and is a topic of speculation. Other drugs with anti Blastocystis activity and used in therapy includes trimethoprim sulfamethoxazole and nitazoxanide. Several other compounds have also been evaluated for the treatment either alone or in combination with the first or second line drugs. A lot of interest has also been generated on the role of probiotics particularly Saccharomyces boularrdii and other natural food compounds on eradication of the parasite. This review provides a comprehensive overview of antimicrobials used to target Blastocystis and discusses the issues pertaining to drug resistance, treatment failure, reinfection, and the current views on treatment modalities.
Blastocystis hominis; metronidazole; nitazoxanide; trimethoprim-sulfamethoxazole
Flavonoids, secondary plant products which could be essential for normal physiology in humans and animals, may be the vitamins of the next century. Flavonoids belong to the polyphenols and possess antioxidative, anti-inflammatory, antimutagenic and anticarcinogenic properties. Among the various flavonoid species, tea flavonoids such as apigenin (from camomile) and epigallocatechin gallate (EGCG from green tea) can be used for the prevention of intestinal neoplasia, especially for adenoma and cancer prevention in the gastrointestinal tract. Numerous experimental studies with molecular and biological end points support the therapeutic efficacy of bioflavonoids. Clinical studies with cohorts and case-control trials suggest that flavonoids are effective in tertiary bioprevention but, as yet, there are no controlled randomized clinical trials. Flavonoids can inhibit inflammatory pathways and could be useful for chronic inflammatory bowel diseases. Flavonoid deficiency syndromes could be therapeutic targets in the future.
Flavonoids; Intestinal neoplasia; Cancer prevention; Apigenin; Epigallocatechin gallate; Inhibition of colon cancer cells
The increasing shortage of donors and the adverse effects of immunosuppression have restricted the impact of solid organ transplantation. Despite the initial promising developments in xenotransplantation, roadblocks still need to be overcome and this form of organ support remains a long way from clinical practice. While hepatocyte transplantation may be effectively correct metabolic defects, it is far less effective in restoring liver function than liver transplantation. Tissue engineering, using extracellular matrix scaffolds with an intact but decellularized vascular network that is repopulated with autologous or allogeneic stem cells and/or adult cells, holds great promise for the treatment of failure of organs within gastrointestinal tract, such as end-stage liver disease, pancreatic insufficiency, bowel failure and type 1 diabetes. Particularly in the liver field, where there is a significant mortality of patients awaiting transplant, human bioengineering may offer a source of readily available organs for transplantation. The use of autologous cells will mitigate the need for long term immunosuppression thus removing a major hurdle in transplantation.
Regenerative medicine; Tissue engineering; Organ transplantation; Cellular transplantation; Xenotransplantation
The present study was aimed to investigate the effects of infusion of different fluids combined with controlled hypotension on gastric intramucosal pH (pHi) and postoperative gastrointestinal function in patients undergoing hepatocarcinoma surgery. Forty-five patients (ASA II) scheduled for surgical resection of hepatocarcinoma undergoing controlled hypotension were randomly assigned to three groups and received infusion of 20 mL/kg Ringer's solution (R group), 6% HAES(H group) or 6% Voluven group (W group). Intragastric PgCO2, pHi, hematocrit and hemoglobin were measured. The significant decrease of pHi and increase of PgCO2 were produced at 1 and 2 h after controlled hypotension in the R group (P < 0.05 or P < 0.01). The time of bowel movement after operation was shorter in the W group than the R group. Meanwhile, we also did not find obvious difference in blood gas indexes among the three groups. The infusion of HAES and Voluven during controlled hypotension could improve gastrointestinal perfusion and accelerate the recovery of postoperative gastrointestinal function.
hemodilution; controlled hypotension; gastric mucosa