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1.  Comparison of Methods for Detection of Blastocystis Infection in Routinely Submitted Stool Samples, and also in IBS/IBD Patients in Ankara, Turkey 
PLoS ONE  2010;5(11):e15484.
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.
PMCID: PMC2987810  PMID: 21124983
2.  Parasites in Mexican patients with irritable bowel syndrome: a case-control study 
Parasites & Vectors  2010;3:96.
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.
PMCID: PMC2964652  PMID: 20942938
3.  Prevalence and Clinical Features of Blastocystis hominis Infection among Patients in Sebha, Libya 
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.
PMCID: PMC3086416  PMID: 21654943
Blastocystis; Seasonal variation; Culture; Diarrhoea
4.  Oh my aching gut: irritable bowel syndrome, Blastocystis, and asymptomatic infection 
Parasites & Vectors  2008;1:40.
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.
PMCID: PMC2627840  PMID: 18937874
5.  Incidence and risk factors of Blastocystis infection in an orphanage in Bangkok, Thailand 
Parasites & Vectors  2012;5:37.
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.
PMCID: PMC3299613  PMID: 22330427
6.  Diagnostic value of the Manning criteria in irritable bowel syndrome. 
Gut  1990;31(1):77-81.
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.
PMCID: PMC1378344  PMID: 2318433
7.  Development and Evaluation of a Real-Time PCR Assay for Detection and Quantification of Blastocystis Parasites in Human Stool Samples: Prospective Study of Patients with Hematological Malignancies▿ 
Journal of Clinical Microbiology  2011;49(3):975-983.
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.
PMCID: PMC3067686  PMID: 21177897
8.  Blastocystis ratti Induces Contact-Independent Apoptosis, F-Actin Rearrangement, and Barrier Function Disruption in IEC-6 Cells  
Infection and Immunity  2006;74(7):4114-4123.
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.
PMCID: PMC1489721  PMID: 16790785
9.  Blastocystis ratti Contains Cysteine Proteases That Mediate Interleukin-8 Response from Human Intestinal Epithelial Cells in an NF-κB-Dependent Manner▿  
Eukaryotic Cell  2007;7(3):435-443.
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.
PMCID: PMC2268520  PMID: 18156286
10.  Prevalence, predictors and clinical significance of Blastocystis sp. in Sebha, Libya 
Parasites & Vectors  2013;6:86.
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.
PMCID: PMC3626707  PMID: 23566585
Blastocystis; Gastrointestinal symptoms; Sebha; Libya
11.  A Metronidazole-Resistant Isolate of Blastocystis spp. Is Susceptible to Nitric Oxide and Downregulates Intestinal Epithelial Inducible Nitric Oxide Synthase by a Novel Parasite Survival Mechanism ▿  
Infection and Immunity  2011;79(12):5019-5026.
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.
PMCID: PMC3232666  PMID: 21930763
12.  Blastocystis: Consensus of treatment and controversies 
Tropical Parasitology  2013;3(1):35-39.
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.
PMCID: PMC3745668  PMID: 23961439
Blastocystis hominis; metronidazole; nitazoxanide; trimethoprim-sulfamethoxazole
13.  Diagnosis and subtype analysis of Blastocystis sp. in 442 patients in a hospital setting in the Netherlands 
BMC Infectious Diseases  2013;13:389.
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.
PMCID: PMC3765316  PMID: 23972160
Blastocystis; Diagnosis; Microscopy; PCR; Molecular epidemiology
14.  Association of symptoms with gastrointestinal microbiota in irritable bowel syndrome 
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.
PMCID: PMC2945484  PMID: 20857523
Irritable bowel syndrome; Self-reported symptoms; Gastrointestinal microbiota; Quantitative real-time polymerase chain reaction
15.  Gastrointestinal and Psychological Mediators of Health-Related Quality of Life in IBS and IBD: A Structural Equation Modeling Analysis 
The American journal of gastroenterology  2011;107(3):10.1038/ajg.2011.377.
Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) are chronic gastrointestinal (GI) syndromes in which both GI and psychological symptoms have been shown to negatively impact health-related quality of life (HRQOL). The objective of this study was to use structural equation modeling (SEM) to characterize the interrelationships among HRQOL, GI, and psychological symptoms to improve our understanding of the illness processes in both conditions.
Study participants included 564 Rome positive IBS patients and 126 IBD patients diagnosed via endoscopic and / or tissue confirmation. All patients completed questionnaires to assess bowel symptoms, psychological symptoms (SCL-90R), and HRQOL (SF-36). SEM with its two components of confirmatory analyses and structural modeling were applied to determine the relationships between GI and psychological symptoms and HRQOL within the IBS and IBD groups.
For both IBD and IBS, psychological distress was found to have a stronger direct effect on HRQOL(−0.51 and −0.48 for IBS and IBD, respectively) than GI symptoms (−0.25 and −0.28). The impact of GI symptoms on psychological distress was stronger in IBD compared with IBS (0.43 vs. 0.22; P <0.05). The indirect effect of GI symptoms on HRQOL operating through psychological distress was significantly higher in IBD than IBS (−0.21 vs. −0.11; P <0.05).
Psychological distress is less dependent on GI symptom severity in IBS compared with IBD even though the degree that psychological distress impacts HRQOL is similar. The findings emphasize the importance of addressing psychological symptoms in both syndromes.
PMCID: PMC3855477  PMID: 22085819
16.  Increased prevalence of gastrointestinal symptoms in patients with allergic disease 
Postgraduate Medical Journal  2007;83(977):182-186.
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.
PMCID: PMC2599996  PMID: 17344573
17.  Practice guidance on the management of acute and chronic gastrointestinal problems arising as a result of treatment for cancer 
Gut  2011;61(2):179-192.
The number of patients with chronic gastrointestinal (GI) symptoms after cancer therapies which have a moderate or severe impact on quality of life is similar to the number diagnosed with inflammatory bowel disease annually. However, in contrast to patients with inflammatory bowel disease, most of these patients are not referred for gastroenterological assessment. Clinicians who do see these patients are often unaware of the benefits of targeted investigation (which differ from those required to exclude recurrent cancer), the range of available treatments and how the pathological processes underlying side effects of cancer treatment differ from those in benign GI disorders. This paper aims to help clinicians become aware of the problem and suggests ways in which the panoply of syndromes can be managed.
A multidisciplinary literature review was performed to develop guidance to facilitate clinical management of GI side effects of cancer treatments.
Different pathological processes within the GI tract may produce identical symptoms. Optimal management requires appropriate investigations and coordinated multidisciplinary working. Lactose intolerance, small bowel bacterial overgrowth and bile acid malabsorption frequently develop during or after chemotherapy. Toxin-negative Clostridium difficile and cytomegalovirus infection may be fulminant in immunosuppressed patients and require rapid diagnosis and treatment. Hepatic side effects include reactivation of viral hepatitis, sinusoidal obstruction syndrome, steatosis and steatohepatitis. Anticancer biological agents have multiple interactions with conventional drugs. Colonoscopy is contraindicated in neutropenic enterocolitis but endoscopy may be life-saving in other patients with GI bleeding. After cancer treatment, simple questions can identify patients who need referral for specialist management of GI symptoms. Other troublesome pelvic problems (eg, urinary, sexual, nutritional) are frequent and may also require specialist input. The largest group of patients affected by chronic GI symptoms are those who have been treated with pelvic radiotherapy. Their complex symptoms, often caused by more than one diagnosis, need systematic investigation by gastroenterologists when empirical treatments fail. All endoscopic and surgical interventions after radiotherapy are potentially hazardous as radiotherapy may induce significant local ischaemia. The best current evidence for effective treatment of radiation-induced GI bleeding is with sucralfate enemas and hyperbaric oxygen therapy.
All cancer units must develop simple methods to identify the many patients who need help and establish routine referral pathways to specialist gastroenterologists where patients can receive safe and effective treatment. Early contact with oncologists and/or specialist surgeons with input from the patient's family and friends often helps the gastroenterologist to refine management strategies. Increased training in the late effects of cancer treatment is required.
PMCID: PMC3245898  PMID: 22057051
Cancer; gastrointestinal; late effects; side effects; toxicity; guidelines; management; symptoms; chemotherapy; radiotherapy; surgery; biological agents; symptoms; physiology; nausea; vomiting; diarrhoea; steatorrhoea; mucus; pain; bleeding; weight loss; stricture
18.  Endoscopic Experience Improves Interobserver Agreement in the Grading of Esophagitis by Los Angeles Classification: Conventional Endoscopy and Optimal Band Image System 
Gut and Liver  2013;8(2):154-159.
Interobserver variation by experience was documented for the diagnosis of esophagitis using the Los Angeles classification. The aim of this study was to evaluate whether interobserver agreement can be improved by higher levels of endoscopic experience in the diagnosis of erosive esophagitis.
Endoscopic images of 51 patients with gastroesophageal reflux disease (GERD) symptoms were obtained with conventional endoscopy and optimal band imaging (OBI). Endoscopists were divided into an expert group (16 gastroenterologic endoscopic specialists guaranteed by the Korean Society of Gastrointestinal Endoscopy) and a trainee group (individuals with fellowships, first year of specialty training in gastroenterology). All endoscopists had no or minimal experience with OBI. GERD was diagnosed using the Los Angeles classification with or without OBI.
The mean weighted paired κ statistics for interobserver agreement in grading erosive esophagitis by conventional endoscopy in the expert group was better than that in the trainee group (0.51 vs 0.42, p<0.05). The mean weighted paired k statistics in the expert group and in the trainee group based on conventional endoscopy with OBI did not differ (0.42, 0.42).
Interobserver agreement in the expert group using conventional endoscopy was better than that in the trainee group. Endoscopic experience can improve the interobserver agreement in the grading of esophagitis using the Los Angeles classification.
PMCID: PMC3964265  PMID: 24672656
Gastroesophageal reflux; Agreement; Experience
19.  Clinical significance of Blastocystis hominis. 
Journal of Clinical Microbiology  1989;27(11):2407-2409.
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.
PMCID: PMC267045  PMID: 2808664
20.  Genome sequence of the stramenopile Blastocystis, a human anaerobic parasite 
Genome Biology  2011;12(3):R29.
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.
PMCID: PMC3129679  PMID: 21439036
21.  Acceptability, effectiveness, and cost-effectiveness of internet-based exposure treatment for irritable bowel syndrome in a clinical sample: a randomized controlled trial 
BMC Gastroenterology  2011;11:110.
Internet-based cognitive behavior therapy (ICBT) has shown promising effects in the treatment of irritable bowel syndrome (IBS). However, to date no study has used a design where participants have been sampled solely from a clinical population. We aimed to investigate the acceptability, effectiveness, and cost-effectiveness of ICBT for IBS using a consecutively recruited sample from a gastroenterological clinic.
Sixty-one patients were randomized to 10 weeks of ICBT (n = 30) or a waiting list control (n = 31). The ICBT was guided by an online therapist and emphasized acceptance of symptoms through exposure and mindfulness training. Severity of IBS symptoms was measured with the Gastrointestinal symptom rating scale - IBS version (GSRS-IBS). Patients in both groups were assessed at pre- and post-treatment while only the ICBT group was assessed 12 months after treatment completion. Health economic data were also gathered at all assessment points and analyzed using bootstrap sampling.
Fifty of 61 patients (82%) completed the post-treatment assessment and 20 of 30 patients (67%) in the ICBT group were assessed at 12-month follow-up. The ICBT group demonstrated significantly (p < .001) larger improvements on the IBS-related outcome scales than the waiting list group. The between group effect size on GSRS-IBS was Cohen's d = 0.77 (95% CI: 0.19-1.34). Similar effects were noted on measures of quality of life and IBS-related fear and avoidance behaviors. Improvements in the ICBT group were maintained at 12-month follow-up. The ICBT condition was found to be more cost-effective than the waiting list, with an 87% chance of leading to reduced societal costs combined with clinical effectiveness. The cost-effectiveness was sustained over the 12-month period.
ICBT proved to be a cost-effective treatment when delivered to a sample recruited from a gastroenterological clinic. However, many of the included patients dropped out of the study and the overall treatment effects were smaller than previous studies with referred and self-referred samples. ICBT may therefore be acceptable and effective for only a subset of clinical patients. Study dropout seemed to be associated with severe symptoms and large impairment. Objective and empirically validated criteria to select which patients to offer ICBT should be developed.
Trial Registration NCT00844961
PMCID: PMC3206465  PMID: 21992655
22.  Human leukocyte antigen DQ2/8 prevalence in non-celiac patients with gastrointestinal diseases 
AIM: To investigate the prevalence of human leukocyte antigen (HLA) DQ2/8 alleles in Southern Italians with liver and gastrointestinal (GI) diseases outside of celiac disease.
METHODS: HLA DQ2/8 status was assessed in 443 patients from three ambulatory gastroenterology clinics in Southern Italy (University of Federico II, Naples, Loreto Crispi Hospital, Ruggi D’Aragona Hospital, Salerno). Patients were grouped based on disease status [pre-post transplant liver disease, esophageal/gastric organic and functional diseases, irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD)] and DQ2/8 alleles, which correspond to a celiac disease genetic risk gradient. Subject allele frequencies were compared to healthy Italian controls.
RESULTS: One hundred and ninety-six out of four hundred and forty-three (44.2%) subjects, median age 56 years and 42.6% female, were DQ2/8 positive. When stratifying by disease we found that 86/188 (45.7%) patients with liver disease were HLA DQ2/8 positive, 39/73 (53.4%) with functional upper GI diseases and 19/41 (46.3%) with organic upper GI diseases were positive. Furthermore, 38/105 (36.2%) patients with IBS and 14/36 (38.9%) with IBD were HLA DQ2/8 positive (P = 0.21). Compared to healthy controls those with functional upper GI diseases disorders had a 1.8 times higher odds of DQ2/8 positivity. Those with liver disease had 1.3 times the odds, albeit not statistically significant, of DQ2/8 positivity. Both those with IBS and IBD had a lower odds of DQ2/8 positivity compared to healthy controls.
CONCLUSION: The proportion of individuals HLA DQ2/8 positive is higher in those with liver/upper functional GI disease and lower in IBS/IBD as compared to general population estimates.
PMCID: PMC3646141  PMID: 23674852
Human leukocyte antigen DQ2/8; Gastro-intestinal and liver disease; Celiac disease
23.  Cushing's disease presenting with gastrointestinal perforation: a case report 
Gastrointestinal perforation is a complication associated with steroid therapy or hypercortisolism, but it is rarely observed in patients with Cushing's disease in clinical practice, and only one case has been reported as a presenting symptom. Herein, we report a rare case of Cushing's disease in which a patient presented with gastrointestinal perforation as a symptom. A 79-year-old man complained of discomfort in the lower abdomen for 6 months. Based on the endocrinological and gastroenterological examinations, he was diagnosed with Cushing's disease with a perforation of the descending colon. After consultation with a gastroenterological surgeon, it was decided that colonic perforation could be conservatively observed without any oral intake and treated with parenteral administration of antibiotics because of the mild systemic inflammation and lack of abdominal guarding. Despite the marked elevated levels of serum cortisol, oral medication was not an option because of colonic perforation. Therefore, the patient was submitted to endonasal adenomectomy to normalize the levels of serum cortisol. Subsequently, a colostomy was successfully performed. Despite its rarity, physicians should be aware that gastrointestinal perforation may be associated with hypercortisolism, especially in elderly patients, and immediate diagnosis and treatment of this life-threatening condition are essential. If a perforation can be conservatively observed, endonasal adenomectomy prior to laparotomy is an alternative treatment option for hypercortisolism.
Learning points
Thus far, only one case of gastrointestinal perforation as a presenting clinical symptom of Cushing's disease has been reported.Physicians should be aware that gastrointestinal perforation might be associated with hypercortisolism in elderly patients because elevated levels of serum cortisol may mask the clinical signs of perforation. Because of this masking effect, the diagnosis of the perforation also tends to be delayed.Although parenteral administration of etomidate is a standard treatment option for decreasing the elevated levels of serum cortisol, endonasal adenomectomy prior to laparotomy is an alternative treatment option if etomidate therapy is unavailable.
PMCID: PMC3922247  PMID: 24616779
24.  New techniques in the tissue diagnosis of gastrointestinal neuromuscular diseases 
Gastrointestinal neuromuscular diseases are a clinically heterogeneous group of disorders of children and adults in which symptoms are presumed or proven to arise as a result of neuromuscular (including interstitial cell of Cajal) dysfunction. Common to most of these diseases are symptoms of impaired motor activity which manifest as slowed or obstructed transit with or without evidence of transient or persistent radiological visceral dilatation. A variety of histopathological techniques and allied investigations are being increasingly applied to tissue biopsies from such patients. This review outlines some of the more recent advances in this field, particularly in the most contentious area of small bowel disease manifesting as intestinal pseudo-obstruction.
PMCID: PMC2653311  PMID: 19132769
Enteric myopathy; Enteric neuropathy; Interstitial cells of Cajal; Intestinal pseudo-obstruction; Visceral pain
25.  Blastocystis: Genetic diversity and molecular methods for diagnosis and epidemiology 
Tropical Parasitology  2013;3(1):26-34.
Blastocystis, an unusual anaerobic, single-celled stramenopile, is a remarkably successful intestinal parasite of a vast array of host species including humans. Fecal Deoxyribonucleic acid (DNA) analysis by nucleic-acid based methods in particular has led to significant advances in Blastocystis diagnostics and research over the past few years enabling accurate identification of carriers and molecular characterization by high discriminatory power. Moreover, Blastocystis comprises a multitude of subtypes (STs) (arguably species) many of which have been identified only recently and molecular epidemiological studies have revealed a significant difference in the distribution of STs across host species and geographical regions. Having a cosmopolitan distribution, the parasite is a common laboratory finding in the stools of individuals with and without intestinal symptoms across the entire globe and while the parasite remains extremely difficult to eradicate and isolate in culture, appropriate molecular tools are now available to resolve important questions such as whether the clinical outcome of colonization is linked to ST and whether Blastocystis is transmitted zoonotically. This review summarizes some of the recent advances in the molecular diagnosis of Blastocystis and gives an introduction to Blastocystis STs, including a recommendation of subtyping methodology based on recent data and method comparisons. A few suggestions for future directions and research areas are given in the light of relevant technological advances and the availability of mitochondrial and nuclear genomes.
PMCID: PMC3745667  PMID: 23961438
Blastocystis; deoxyribonucleic acid; diagnosis; epidemiology; polymerase chain reaction

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