Protozoan parasites in irritable bowel syndrome: A case-control study

The Role of Blastocystis spp. in the Etiology of Gastrointestinal and Autoimmune Diseases

Blastocystis spp. has been linked to gastrointestinal symptoms, yet its pathogenicity remains uncertain. In addition, the roles of virulence factors, pathogenic potential, and host-specific traits associated with symptomatic infections are still not well understood. The growing number of immunocompromised patients has contributed to an increasing prevalence of Blastocystis spp. infections, which may be implicated in the development of various inflammatory diseases, including irritable bowel syndrome (IBS), colorectal cancer, and autoimmune disorders such as Hashimoto's disease and ulcerative colitis. However, the presence of nonspecific symptoms often complicates diagnosis. This study aimed to present current data on the impact of Blastocystis spp. on the development and progression of gastrointestinal and autoimmune diseases, as well as to explore potential treatment options for Blastocystis spp. infections. A literature review was conducted to analyze the role of Blastocystis spp. in the pathogenesis of specific diseases and to investigate potential mechanisms of its interaction with the host organism. Advances in diagnostic techniques, particularly PCR, allow not only for the detection of Blastocystis spp. but also for the identification of specific subtypes, improving treatment precision. Beyond conventional therapies like metronidazole, there is a growing emphasis on alternative treatments, including the use of medicinal plants and probiotics.

Blastocystis hominis; Friend or Foe

Blastocystis hominis (B. hominis) remains the most common parasite identified through stool examination. A clinician will undoubtedly encounter the presence of this parasite numerous times in their career. Thus, it is vital to know if this organism is a 'friend or foe', or in other words, whether it is a commensal or a pathogen. This will help clinicians decide whether to treat or not. This literature review discusses the best available evidence of the association of B. hominis and two diseases- irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Particularly, focus has been paid to the effect of antimicrobial therapy in improving disease activity/symptoms and concluding on the pathogenicity of B. hominis based on in vitro, observational studies, and randomized controlled trials. Most importantly, the review presents a concise set of recommendations for when and how to treat B. hominis in a patient presenting gastrointestinal ailments.

Molecular characterization of Giardia duodenalis, Cryptosporidium spp., and Entamoeba spp. infecting domestic and feral/stray cats in Jordan

This study aimed to carry out a molecular screening for the presence of Giardia, Cryptosporidium, and/or Entamoeba in the feces of pet and stray/feral cats in Jordan. G. duodenalis was found in 27.9% (95% CI, 23.2-32.9) of the 348 sampled cats overall; E. histolytica was found in only 0.6% (95% CI, 0.1-2.1) of the cats, while none of the sampled cats had Cryptosporidium infections. The infection rate of G. duodenalis among indoor cats (32.3%) did not differ significantly from that among outdoor cats (24.1%). There were significantly more infections (p = 0.0004) geographically in the cold semiarid areas (67%) than in the cold desert areas (24%). Multilocus sequence typing analysis of amplicons based on the bg, tpi, and gdh genes revealed that the majority of G. duodenalis infections were zoonotic assemblage B (65.9%; 64 of 97 positive samples); followed by feline-specific assemblage F (18.5%, 18/97); cattle-specific assemblage E (5.2%, 5/97); and then assemblage C that was shared with canids (1.0%; 1/97). Within Giardia isolates, a substitution mutation (A/G) was found at position 297 of the complete protein coding sequence (cds) of tpi-assemblage B, which may represent a new spreading mutation within this gene among the cat population in Jordan. The results of the present study suggest that close human-cat interactions could play a role in zoonotic transmission of Giardia, but further research is needed to determine the possible contribution of cats to the transmission of other protozoa to humans.

Blastocystis spp. and Other Intestinal Parasites in Polish Soldiers Deployed to Lebanon and Iraq

Intestinal parasitic infections are one of the most common infectious diseases worldwide, particularly in developing countries. A distinct group at increased risk of infection is military personnel deployed overseas for extended periods, typically six months at a time. The aim of this study was to determine the prevalence of Blastocystis spp. and other intestinal parasites in Polish military personnel returning from deployments to Lebanon (n = 206) and Iraq (n = 220). In this group of subjects, we found Blastocystis spp. (13.6%), Dientamoeba fragilis (3.3%), Entamoeba coli (0.9%), and Endolimax nana (0.5%). Entamoeba histolytica sensu lato and Chilomastix mesnili infections were detected only in one soldier returning from Lebanon and Iraq, respectively. Blastocystis subtype (ST) 3 was predominant in soldiers returning from Lebanon, followed by ST2 and ST1. ST1 infection was predominant in soldiers returning from Iraq, followed by ST3 and ST2. Our study affirms that, deployment abroad is of no influence of the prevalence of parasitic protozoa. However, it would be worth to monitor parasite infection in military personnel returning from tropical zone even if they have no actual symptoms. In addition, it is very important to determine the subtypes of Blastocystis-this may help to clearly define their pathogenicity, especially considering the scarcity of studies on Blastocystis genotypes in Iraqi and Lebanese residents.

Cryptosporidium and irritable bowel syndrome

Cryptosporidium is an apicomplexan parasite that causes gastrointestinal disease in a wide variety of hosts and is associated with waterborne outbreaks. Nonetheless, the parasite is underdiagnosed. Cryptosporidium has been proposed as an etiological cause of irritable bowel syndrome (IBS) in several studies. However, the exact mechanism of pathogenesis is unknown, and no direct link has been discovered. This review will discuss several parasite-induced modifications, such as immunological, microbiome, and metabolite modifications, as well as their interactions. To summarize, Cryptosporidium causes low inflammation, dysbiosis, and unbalanced metabolism, which leads to a lack of homeostasis in the intestine in a comparable pattern to postinfectious IBS.

Interactions between free-living amoebae and Cryptosporidium parvum: an experimental study

Free-Living Amebae (FLA) and Cryptosporidium oocysts occasionally share the same environment. From 2004 to 2016, Cryptosporidium was responsible for 60% of 905 worldwide waterborne outbreaks caused by protozoan parasites. The aim of this study was to evaluate interactions between C. parvum oocysts and two common FLAs (Acanthamoeba castellanii and Vermamoeba vermiformis) in a water environment. Encystment and survival of FLAs were evaluated by microscopy using trypan blue vital coloration. Oocysts were numerated on microscopy. Interactions were studied over time in conditions both unfavorable and favorable to phagocytosis. Potential phagocytosis was directly evaluated by several microscopic approaches and indirectly by numeration of microorganisms and oocyst infectivity evaluation. Occasional phagocytosis of C. parvum by FLAs was documented. However, oocyst concentrations did not decrease significantly, suggesting resistance of oocysts to phagocytosis. A temporary decrease of oocyst infectivity was observed in the presence of A. castellanii. The effect of these interactions on C. parvum infectivity is particularly interesting. The biofilm condition could favor the persistence or even the proliferation of oocysts over time. This study demonstrated interactions between C. parvum and FLAs. Further knowledge of the mechanisms involved in the decrease of oocyst infectivity in the presence of A. castellanii could facilitate the development of new therapeutic approaches.

The Potential Role of Gut Bacteriome Dysbiosis as a Leading Cause of Periprosthetic Infection: A Comprehensive Literature Review

(1) Background: Periprosthetic joint infections (PJIs) represent a small yet important risk when undertaking a joint arthroplasty; they occur in approximately 1-2% of treatments. These infections create a medical and financial burden for patients and healthcare systems. Despite the introduction of recognized best clinical practices during arthroplasty operations, it is not yet possible to further reduce the risk of infection after surgery. The purpose of this review is to raise awareness of the potential role of gut dysbiosis in the development of PJIs and to highlight the potential of the gut bacteriome as a possible target for preventing them. (2) Methods: We compiled all the available data from five databases, examining the effects of gut dysbiosis in human and murine studies, following PRISMA guidelines, for a total of five reviewed studies. (3) Results: One human and one murine study found the Trojan horse theory applicable. Additionally, inflammatory bowel diseases, gut permeability, and oral antibiotic ingestion all appeared to play a role in promoting gut dysbiosis to cause PJIs, according to the other three studies. (4) Conclusions: Gut dysbiosis is linked to an increased risk of PJI.

Gut Microbiota Shifting in Irritable Bowel Syndrome: The Mysterious Role of Blastocystis sp

Irritable bowel syndrome (IBS) is a chronic disorder, which its causative agent is not completely clear; however, the interaction between microorganisms and gastrointestinal (GI) epithelial cells plays a critical role in the development of IBS and presenting symptoms. During recent decades, many studies have highlighted the high prevalence of Blastocystis sp. in patients with IBS and suggested a probable role for this protist in this disease. Recent studies have documented changes in the gut microbiota composition in patients with IBS regarding the presence of Blastocystis sp., but it is not clear that either disturbance of the gut during GI disorders is a favorable condition for Blastocystis sp. colonization or the presence of this protist may lead to alteration in the gut microbiota in IBS patients. In this review, we comprehensively gather and discuss scientific findings covering the role of Blastocystis sp. in IBS via gut microbiota shifting.

How the gut parasitome affects human health

The human gut microbiome (GM) is a complex ecosystem that includes numerous prokaryotic and eukaryotic inhabitants. The composition of GM can influence an array of host physiological functions including immune development. Accumulating evidence suggest that several members of non-bacterial microbiota, including protozoa and helminths, that were earlier considered as pathogens, could have a commensal or beneficial relationship with the host. Here we examine the most recent data from omics studies on prokaryota-meiofauna-host interaction as well as the impact of gut parasitome on gut bacterial ecology and its role as 'immunological driver' in health and disease to glimpse new therapeutic perspectives.

Review article: Diagnosis and investigation of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction. It is defined by the Rome criteria as the presence of abdominal pain, related to defaecation, associated with a change in stool form and/or frequency. The approach to diagnosis and investigation of suspected IBS varies between clinicians and, due in part to the uncertainty that can surround the diagnosis, many still consider it to be a diagnosis of exclusion. However, exhaustive investigation is both unnecessary and costly, and may also be counterproductive. Instead, physicians should aim to make a positive diagnosis, based on their clinical assessment of symptoms, and limit their use of investigations. The yield of routine blood tests in suspected IBS is low overall, but normal inflammatory markers may be reassuring. All patients should have serological testing for coeliac disease, irrespective of their predominant stool form. Routine testing of stool microbiology or faecal elastase is unnecessary; however, all patients with diarrhoea aged <45 should have a faecal calprotectin or a similar marker measured which, if positive, should lead to colonoscopy to exclude possible inflammatory bowel disease. Colonoscopy should also be undertaken in any patient reporting alarm symptoms suggestive of colorectal cancer, and in those whose presentation raises suspicion for microscopic colitis. Testing for bile acid diarrhoea should be considered for patients with IBS with diarrhoea where available. Hydrogen breath tests for lactose malabsorption or small intestinal bacterial overgrowth have no role in the routine assessment of suspected IBS. Adopting a standardised approach to the diagnosis and investigation of IBS will help to promote high-quality and high-value care for patients overall.

Molecular characterization of Entamoeba, Blastocystis and Cryptosporidium species in stool samples collected from Jordanian patients suffering from gastroenteritis

Little is known about the prevalence of intestinal protozoa in patients suffering from diarrhea in Jordan. The present study aimed to detect and speciate Entamoeba, Blastocystis, and Cryptosporidium species in a total of 159 human patients with diarrhea from November 2014 to October 2016. The overall prevalence for the three parasites was 19.5% (31/159). Entamoeba spp. (Entamoeba. dispar and/or Entamoeba histolytica), Blastocystis hominis, and Cryptosporidium parvum subtype IIaA15G2R1 were detected in 12.6%, 6%, and 0.6 of samples, respectively. This is the first molecular study in Jordan to confirm the diagnosis of Entamoeba species and to discriminate between E. histolytica and E. dispar.

Treatment of human intestinal cryptosporidiosis: A review of published clinical trials

The global burden of diarrhea caused by Cryptosporidium parasite is underestimated. In immunocompromised hosts, chronic and severe presentation of intestinal cryptosporidiosis can result in long-term morbidity and high illness costs. The evidence of effective treatments for cryptosporidiosis has been lacking. We reviewed the published clinical trials to bring forward the feasible therapeutic options of human cryptosporidiosis in various populations and settings according to clinical improvement and parasite clearance rates. A total of 42 studies consisting of the use of nitazoxanide, paromomycin, macrolides, somatostatin analogues, letrazuril, albendazole, rifaximin, miltefosine, clofazimine, and colostrum were included in the review. The trials were mostly conducted in small number of individuals infected with human immunodeficiency virus (HIV), and there is inadequate data of controlled trials to suggest the use of these treatment modalities. Nitazoxanide was reported to be highly efficacious only in immunocompetent hosts and was found to be superior to paromomycin in the same group of patients. Macrolides showed no effective results in both clinical and parasitological improvement. Human bovine colostrum should possibly be administered as one of complementary therapeutic modalities along with other antimicrobials to reach optimal parasite eradication. Other trials of therapeutic modalities were terminated due to futility. Currently, available data is intended to aid the development of strategies for improving access to treatments in different clinical settings, as well as to help guide further studies on treatments of human intestinal cryptosporidiosis.

Enteric Tuft Cells in Host-Parasite Interactions

Enteric tuft cells are chemosensory epithelial cells gaining attention in the field of host-parasite interactions. Expressing a repertoire of chemosensing receptors and mediators, these cells have the potential to detect lumen-dwelling helminth and protozoan parasites and coordinate epithelial, immune, and neuronal cell defenses against them. This review highlights the versatility of enteric tuft cells and sub-types thereof, showcasing nuances of tuft cell responses to different parasites, with a focus on helminths reflecting the current state of the field. The role of enteric tuft cells in irritable bowel syndrome, inflammatory bowel disease and intestinal viral infection is assessed in the context of concomitant infection with parasites. Finally, the review presents pertinent questions germane to understanding the enteric tuft cell and its role in enteric parasitic infections. There is much to be done to fully elucidate the response of this intriguing cell type to parasitic-infection and there is negligible data on the biology of the human enteric tuft cell—a glaring gap in knowledge that must be filled.

Use-case scenarios for an anti-Cryptosporidium therapeutic

Cryptosporidium is a widely distributed enteric parasite that has an increasingly appreciated pathogenic role, particularly in pediatric diarrhea. While cryptosporidiosis has likely affected humanity for millennia, its recent "emergence" is largely the result of discoveries made through major epidemiologic studies in the past decade. There is no vaccine, and the only approved medicine, nitazoxanide, has been shown to have efficacy limitations in several patient groups known to be at elevated risk of disease. In order to help frontline health workers, policymakers, and other stakeholders translate our current understanding of cryptosporidiosis into actionable guidance to address the disease, we sought to assess salient issues relating to clinical management of cryptosporidiosis drawing from a review of the literature and our own field-based practice. This exercise is meant to help inform health system strategies for improving access to current treatments, to highlight recent achievements and outstanding knowledge and clinical practice gaps, and to help guide research activities for new anti-Cryptosporidium therapies.

Parasitic infections in irritable bowel syndrome patients: evidence to propose a possible link, based on a case-control study in the south of Iran

OBJECTIVES

The current study aimed to evaluate the prevalence of parasitic infections and their possible association with irritable bowel syndrome (IBS), through a case-control study. Stool samples were collected from patients with IBS and healthy subjects and were examined microscopically to detect intestinal parasites.

RESULTS

A total of 200 subjects were enrolled in the study including 100 patients with IBS and 100 healthy controls. The patients were selected based on the Rome III criteria. Of the 100 patients with IBS, 65 (65%) were female and 35 (35%) were male, with a mean age of 42.57 (± 4.07) years. Of these, 30 (30%) were infected with at least one intestinal parasite; the most common ones were Blastocystis hominis and Giardia lamblia. Of the control cases, 64 (64%) were female and 36 (36%) were male, with a mean age of 41.82 (± 11.75) years. Of these, 16 (16%) were infected with at least one intestinal parasite; the most common were B. hominis and Endolimax. There was a significant difference between the rate of parasitic infections between the patients with IBS and the control in particular, B. hominis and G. lamblia. The findings of the study support a possible link between parasitic infections and IBS.

Mucosal Tuft Cell Density Is Increased in Diarrhea-Predominant Irritable Bowel Syndrome Colonic Biopsies

Tuft cells are rare chemosensory sentinels found in the gut epithelium. When triggered by helminth infection, tuft cells secrete interleukin-25 (IL-25) basolaterally and subsequently evoke an immune response. Irritable bowel syndrome (IBS) is a common and heterogeneous disorder characterized by bowel dysfunction and visceral pain sensitivity. Dysfunctional gut-brain communication and immune activation contribute to the pathophysiology of this disorder. The study aims were to investigate changes in tuft cell density in non-post-infectious IBS patients. Immunofluorescent labeling of DCLK1-positive tuft cells was carried out in mucosal biopsies from the distal colons of diarrhea and constipation-predominant IBS patients and healthy controls. Tuft cell numbers were also assessed in animal models. Concentrations of interleukin-25 (IL-25) secreted from colonic biopsies and in plasma samples were analyzed using an immunoassay. The density of tuft cells was increased in diarrhea-but not constipation-predominant IBS patient colonic biopsies. Biopsy secretions and plasma concentrations of IL-25 were elevated in diarrhea-but not constipation-predominant IBS participants. Tuft cell hyperplasia was detected in a rat model of IBS but not in mice exposed to chronic stress. Tuft cell hyperplasia is an innate immune response to helminth exposure. However, the patients with diarrhea-predominant IBS have not reported any incidents of enteric infection. Moreover, rats exhibiting IBS-like symptoms displayed increased tuft cell density but were not exposed to helminths. Our findings suggest that factors other than helminth exposure or chronic stress lead to tuft cell hyperplasia in IBS colonic biopsies.

Genetic Diversity and Distribution of Blastocystis Subtype 3 in Human Populations, with Special Reference to a Rural Population in Central Mexico

Blastocystis subtype 3 (ST3) is a parasitic protist found in the digestive tract of symptomatic and asymptomatic humans around the world. While this parasite exhibits a high prevalence in the human population, its true geographic distribution and global genetic diversity are still unknown. This gap in knowledge limits the understanding of the spread mechanisms, epidemiology, and impact that this parasite has on human populations. Herein, we provided new data on the geographical distribution and genetic diversity of Blastocystis ST3 from a rural human population in Mexico. To do so, we collected and targeted the SSU-rDNA region in fecal samples from this population and further compared its genetic diversity and structure with that previously observed in populations of Blastocystis ST3 from other regions of the planet. Our analyses reveled that diversity of Blastocystis ST3 showed a high haplotype diversity and genetic structure to the world level; however, they were low in the Morelos population. The haplotype network revealed a common widespread haplotype from which the others were generated recently. Finally, our results suggested a recent expansion of the diversity of Blastocystis ST3 worldwide.