Tropheryma whipplei in children with gastroenteritis

Tropheryma whipplei detected by metagenomic next-generation sequencing in bronchoalveolar lavage fluid

Whipple's disease is a chronic systemic infectious disease that mainly affects the gastrointestinal tract. In some cases, Tropheryma whipplei can cause infection at the implant site or even throughout the body. In this study, we collected alveolar lavage fluid samples from patients with Tropheryma whipplei from 2020 to 2022, and retrospectively analyzed the clinical data of Tropheryma whipplei positive patients. Patient's past history, clinical manifestations, laboratory examinations, chest CT findings, treatment, and prognosis were recorded. 16 BALFs (70/1725, 4.0 %) from 16 patients were positive for Tropheryma whipplei. 8 patients were male with an average age of 50 years. The main clinical symptoms of patients included fever (9/16), cough (7/16), dyspnea (7/16), and expectoration (5/16), but neurological symptoms and arthralgia were rare. Cardiovascular and cerebrovascular diseases were the most common comorbidity (n=8). The main laboratory characteristics of the patient are red blood cell count, hemoglobin, total protein and albumin below normal levels (11/16), and/or creatinine above normal levels(14/16). Most chest computed tomography mainly show focal or patchy heterogeneous infection (n=5) and pleural effusion (n=8). Among the 6 samples, Tropheryma whipplei was the sole agent, and Klebsiella pneumoniae was the most common detected other pathogens. Metagenomic next-generation sequencing technology has improved the detection rate and attention of Tropheryma whipplei. Further research is needed to distinguish whether Tropheryma whipplei present in respiratory samples is a pathogen or an innocent bystander.

Whipple Disease Presenting as Isolated Transverse Myelitis with Permanent Neurological Damage in a Patient with Systemic Lupus Erythematosus: A Case Report of a Difficult Diagnosis with a Literature Review

We describe an atypical case of Whipple disease exclusively involving the spinal cord in an adolescent receiving immunosuppressive therapy for systemic lupus erythematosus. The diagnosis was particularly difficult since lupus and Whipple disease can present similar clinical features and the patient's prolonged contact with sewage was initially not mentioned. A literature review of the clinical, imaging, diagnostic, and therapeutic challenges of Whipple disease is also performed.

Whipple's disease: A rare disease that can be spotted by many doctors

Whipple's disease, an extremely rare, chronic infection caused by Tropheryma whipplei, an actinobacterium ubiquitously present in the environment, is a multisystemic condition that can affect several organs. Therefore, Whipple's disease should always be considered by physicians working across various branches of medicine, including internal medicine, rheumatology, infectious diseases, gastroenterology, haematology, and neurology. Initially, Whipple's disease is challenging to diagnose due to both its rarity and non-specific clinical features, almost indistinguishable from rheumatological conditions. A few years later, the onset of gastrointestinal symptoms increases the specificity of its clinical picture and helps in reaching the correct diagnosis. Diagnosis is typically made by finding PAS-positive macrophages in the lamina propria at duodenal biopsy. PCR for Tropheryma whipplei is nowadays also increasingly available, and represents an undeniable help in diagnosing this condition. However, it may also be misleading as false positives can occur. If not promptly recognized and treated, central nervous system involvement may develop, which can be fatal. The therapeutic gold standard has not yet been fully established, particularly in cases of recurrent disease, neurological involvement, and an immune reconstitution inflammatory syndrome that may arise following the initiation of antibiotic therapy.

Prevalence estimation of Tropheryma whipplei in duodenal biopsy tissues of Koreans

Whipple's disease caused by Tropheryma whipplei is difficult to diagnose because of a broad spectrum of manifestations and non-specific clinical signs. In the current global era, the incidence of duodenal infection/inflammation caused by T. whipplei in Korea may has been underestimated. Here we estimated the prevalence of T. whipplei in duodenal biopsy tissues of Koreans using real-time PCRs (RT-PCRs). A total of 252 duodenal biopsy tissues were collected from Korean patients who underwent esophagogastroduodenoscopy and duodenal biopsy. DNA extracted from the duodenal biopsy tissues was analyzed using three RT-PCRs targeting T. whipplei-specific regions of the 16S-23S rRNA intergenic spacer, hsp65, and Dig15 in parallel. In the samples positive in RT-PCRs, direct sequencing was performed for each RT-PCR target. The prevalence of T. whipplei was estimated based on the RT-PCR and sequencing results. Among the analyzed samples, T. whipplei was not detected. The prevalence of T. whipplei in duodenal biopsy tissues of Koreans was estimated to be less than 0.4%. This is the first study to attempt to detect T. whipplei in duodenal biopsy tissues of Koreans and estimate its prevalence. Our findings infer that while T. whipplei carriers exist in Korea, the incidence of duodenal infection/inflammation caused by T. whipplei is extremely rare.

Is Autologous Fecal Microbiota Transfer after Exclusive Enteral Nutrition in Pediatric Crohn’s Disease Patients Rational and Feasible? Data from a Feasibility Test

Background: Exclusive enteral nutrition (EEN) is a highly effective therapy for remission induction in pediatric Crohn’s disease (CD), but relapse rates after return to a regular diet are high. Autologous fecal microbiota transfer (FMT) using stool collected during EEN-induced clinical remission might represent a novel approach to maintaining the benefits of EEN. Methods: Pediatric CD patients provided fecal material at home, which was shipped at 4 °C to an FMT laboratory for FMT capsule generation and extensive pathogen safety screening. The microbial community composition of samples taken before and after shipment and after encapsulation was characterized using 16S rRNA amplicon sequencing. Results: Seven pediatric patients provided fecal material for nine test runs after at least three weeks of nutritional therapy. FMT capsules were successfully generated in 6/8 deliveries, but stool weight and consistency varied widely. Transport and processing of fecal material into FMT capsules did not fundamentally change microbial composition, but microbial richness was <30 genera in 3/9 samples. Stool safety screening was positive for potential pathogens or drug resistance genes in 8/9 test runs. Conclusions: A high pathogen burden, low-diversity microbiota, and practical deficiencies of EEN-conditioned fecal material might render autologous capsule-FMT an unsuitable approach as maintenance therapy for pediatric CD patients.

Uptake of Tropheryma whipplei by Intestinal Epithelia

Background: Tropheryma whipplei (TW) can cause different pathologies, e.g., Whipple’s disease and transient gastroenteritis. The mechanism by which the bacteria pass the intestinal epithelial barrier, and the mechanism of TW-induced gastroenteritis are currently unknown. Methods: Using ex vivo disease models comprising human duodenal mucosa exposed to TW in Ussing chambers, various intestinal epithelial cell (IEC) cultures exposed to TW and a macrophage/IEC coculture model served to characterize endocytic uptake mechanisms and barrier function. Results: TW exposed ex vivo to human small intestinal mucosae is capable of autonomously entering IECs, thereby invading the mucosa. Using dominant-negative mutants, TW uptake was shown to be dynamin- and caveolin-dependent but independent of clathrin-mediated endocytosis. Complementary inhibitor experiments suggested a role for the activation of the Ras/Rac1 pathway and actin polymerization. TW-invaded IECs underwent apoptosis, thereby causing an epithelial barrier defect, and were subsequently subject to phagocytosis by macrophages. Conclusions: TW enters epithelia via an actin-, dynamin-, caveolin-, and Ras-Rac1-dependent endocytosis mechanism and consecutively causes IEC apoptosis primarily in IECs invaded by multiple TW bacteria. This results in a barrier leak. Moreover, we propose that TW-packed IECs can be subject to phagocytic uptake by macrophages, thereby opening a potential entry point of TW into intestinal macrophages.

Whipple's disease review, prevalence, mortality, and characteristics in the United States: A cross-sectional national inpatient study

Whipple's disease is a rare multiorgan systemic disease caused by Tropheryma whipplei infection that may present with a wide range of signs and symptoms. This study aim to comprehensively review and determine the inpatient prevalence, mortality, risk factors, and reasons for hospitalization of patients with Whipple's disease. ICD-10 codes were used to identify admissions with Whipple's disease during the years 2016 to 2018. Characteristics of admissions with and without Whipple's disease were compared. The most common reasons for hospitalization were identified in admissions with Whipple's disease. The prevalence of Whipple's disease was 4.6 per 1 million hospitalizations during the study period. Whipple's disease admissions were significantly older than other hospitalizations, with a mean age of 60.2 ± 1.6 years compared to 50.0 ± 0.1. Males were more likely to have Whipple's disease and represented approximately two-thirds of hospitalizations. A disproportionate number of admissions occurred in the Midwest. Patients with Whipple's disease were most commonly admitted for gastrointestinal disease, followed by systemic infection, cardiovascular/circulatory disease, musculoskeletal disease, respiratory disease, and neurological disease. High mortality was seen in admissions for central nervous system (CNS) disease. Whipple's disease has heterogeneous presentations for inpatient admissions, and disproportionately affects older males. High hospitalization rates in the Midwest support environmental and occupational disease transmission likely from the soil. Hospitalists should be aware of the various acute, subacute, and chronic presentations of this disease, and that acute presentations may be more common in the inpatient setting.

Tropheryma whipplei, Helicobacter pylori, and Intestinal Protozoal Co-Infections in Italian and Immigrant Populations: A Cross-Sectional Study

Tropheryma whipplei (TW), Helicobacter pylori (HP), and intestinal protozoa (IP) are widespread pathogens with similar routes of transmission and epidemiological risk factors. Epidemiological data on co-infection between TW, HP, and IP are scarce. We aim to more deeply investigate the co-infection rate for these pathogens, evaluating the risk factors and symptoms. Methods: This is a cross-sectional study conducted at the IRCCS Sacro Cuore Don Calabria Hospital in Northern Italy, a referral center for tropical and Whipple’s disease (WD). Stored stool samples from 143 subjects previously tested for TW DNA by real-time PCR were explored for HP and IP DNA detection. The virulence factor cagA was investigated in HP-positive patients. Results: A history of migration was reported significantly more in TW-positive than in negative subjects (34.1% vs. 9.1%, p = 0.001) and in HP-infected than in those non-infected (59.1% vs. 9.1%, p < 0.001). The HP infection rate differed significantly between TW-infected and uninfected groups (31.8% vs. 8.1%, p = 0.001), while no difference was observed for IP infection. Significantly higher TW intestinal colonization was found in HP-infected patients than in non-infected (63.6% vs. 24.8%, p < 0.001). In addition, the proportion of Blastocysts positive finding was also significantly higher in HP-infected than in non-infected (40.9% vs. 17.4%, p = 0.018). Conclusions: The present study is the first to report a high TW and HP co-infection rate. To reduce the risk of morbidity from a chronic infection of either pathogen, clinicians may consider TW-HP molecular screening on the same stool sample for patients with suspected HP disease or WD, particularly in case of travel history.

Tropheryma whipplei in the stool samples of children with acute diarrhea: a study from Tehran, Iran

Background

Recently, Tropheryma whipplei has been suggested as one of the causative agents of diarrhea among children worldwide. Limited data is available on the prevalence of T. whipplei among children with diarrhea in most countries such as Iran. This study was conducted to evaluate the prevalence of T. whipplei in children with acute diarrhea in Iran.

Methods

In this study, the stool samples were collected from 130 children under 10 years old with acute diarrhea from children's hospitals in Tehran city. Genomic DNA was extracted from stool samples and was tested for the presence of DNA of T. whipplei using the SYBR Green Real-time PCR method. Positive T. whipplei samples were finally confirmed by PCR Product sequencing.

Results

The mean age of participants was 32.5 months, and 54.6% of children were female. Using the SYBR Green Real-time PCR, 9.23% (12/130) of samples were positive for T. whipplei, which were confirmed by sequencing. 66.67% of positive cases were males. The duration of diarrhea in infected children with T. whipplei (83.3%) was significantly longer (OR: 5.93, 95% CI 1.24–28.22) compared to children with negative results (45.8%). Other demographic factors and clinical signs had not a statistically significant relationship with T. whipplei infection.

Conclusions

In this study, T. whipplei was detected in stool samples of children with acute diarrhea. The results indicated that T. whipplei could be associated with childhood diarrhea in Iran. The health care system and physicians should be aware of the presence of T. whipplei infection in Iran, especially in childhood diarrhea.

Tropheryma whipplei Detection by Nanopore Sequencing in Patients With Interstitial Lung Disease

Tropheryma whipplei is a bacterium associated with Whipple's disease, which commonly manifests as weight loss, arthralgia, and diarrhea. The most frequently involved organs comprise the heart and eyes, in addition to the central nervous system. Few studies have explored the relationship between T. whipplei and pneumonia. Herein, we report three patients with interstitial lung disease (ILD) of unknown cause, whose bronchoalveolar lavage fluid (BALF) were evaluated via Nanopore sequencing. In our in-house BALF Nanopore platform, human DNA was removed with saponin, to improve the reads ratio of microorganisms/host. T. whipplei was the sole or most abundant pathogen in all the patients, comprising 1,385, 826, and 285 reads. The positive result was confirmed via quantitative polymerase chain reaction (PCR) with two pairs of primers (cycle threshold value: 33.26/36.29; 31.68/32.01; 28.82/28.80) and Sanger sequencing. To our knowledge, this is the first report of T. whipplei detection using Nanopore-based sequencing. The turnaround time was approximately 6-8 h in clinical laboratories, including less than 1 h for analysis. In conclusion, the results of this study confirm that Nanopore sequencing can rapidly detect rare pathogens, to improve clinical diagnosis. In addition, diagnosis of Whipple's disease should be combined other laboratory findings, such as periodic acid-Schiff (PAS) staining, and considered a possibility in middle-aged men presenting with ILD and a clinical history of unexplained arthralgia and/or fever.

Tropheryma whipplei intestinal colonization in immunocompromised children in Iran: a preliminary study

Aim & method: Tropheryma whipplei causes Whipple's disease. Children are reservoirs of this bacterium. The aim of this study was to investigate the presence of T. whipplei in children with immunodeficiency in central Iran from July 2018 to February 2019. Stool samples were tested by SYBR Green and Taq-Man real-time PCR assays. For confirmation, the isolated DNA was sequenced. Results: One hundred and thirty children were enrolled. Acute lymphocytic leukemia was the most reported immunodeficient disease (77%), followed by non-Hodgkin lymphoma and retinoblastoma. Thirteen (10%) children had T. whipplei DNA in the stool; 11.4% of the children under 5 years old were positive. Conclusion: This is the first study showing the circulation of T. whipplei in Iran.

Tropheryma whipplei in Feces of Patients with Diarrhea in 3 Locations on Different Continents

We examined fecal specimens of patients with diarrhea from 3 continents for Tropheryma whipplei and enteropathogens. T. whipplei was most common in South Africa, followed by Singapore and Germany. Its presence was associated with the presence of other pathogens. An independent causative role in diarrhea appears unlikely.

Phenotypic diversity of Tropheryma whipplei clinical isolates

Tropheryma whipplei is a bacterial pathogen responsible for a wide range of infections in humans, covering asymptomatic carriage, acute infections, chronic isolated infections and classic Whipple's disease. Although the bacterium is commonly found in the environment, it very rarely causes disease. Genetic comparison of clinical isolates has revealed that main variations were found in region encoding T. whipplei surface glycoproteins called WiSP. However, no association has been made between the genetic diversity and the clinical manifestations of the infection. In this study we evaluated the phenotypic diversity of 26 clinical isolates from different origins and taken from patient with different infection outcomes. MRC5 and macrophages cells were infected, and bacterial uptake, survival and the pro-and anti-inflammatory potential of the different clinical isolates was assessed. No significant difference of phagocytosis was found between the different isolates; however, we found that bacterial replication was increased for bacteria expressing high molecular weight WiSP. In addition, we found that the expression of the genes coding for IL-1β and TGF-β was significantly higher when MRC5 cells were stimulated with isolates from chronic infections compared to isolates from localized infections while no significant differences were observed in macrophages. Overall, our study revealed that, as previously observed at the genetic level, phenotypic diversity of T. whipplei isolates is associated with the expression of different WiSP, which may result in subtle differences in host responses. Other host factors or genetic predisposition may explain the range of clinical manifestations of T. whipplei infections.

Whipple's disease: diagnosis and predictive factors of relapse

BACKGROUND

Whipple's disease is a very rare disease needing a long-term treatment. The most frequent symptoms are recurrent arthralgia or arthritis, chronic diarrhea, abdominal pain, and weight loss.

OBJECTIVES

In this article, we have highlighted the main clinical features and diagnostic procedures that lead to the diagnosis and comment on the clinical response, treatment, and the factors of relapse.

METHODS

Subjects were recruited from the Internal Medicine and Rheumatologic Departments of an University Hospital from November 1997 to January 2016. Overall, 12 subjects were finally diagnosed.

RESULTS

Mean age was 54.3 years (age range: 30-81), with more male patients (58.3%). Almost all patients had articular symptoms and impaired general condition (91.7%); and a majority had digestive symptoms (75%). Regardless of the symptoms, the most efficient diagnostic tools were the PCR screening on the gastrointestinal biopsies and saliva (83.3 and 72.7% positive results, respectively). More than half of the patients relapsed (55.6%). The relapsing patients were older [63.2 (44-81)] and mostly male with a majority (60%) of digestive symptoms and a delayed diagnosis.

CONCLUSIONS

In current practice, it is highly difficult to diagnose Whipple's disease. In order to decrease the delay between the first symptoms and the diagnosis, effective tools such as saliva and stools PCR should be used because higher delays of diagnosis lead to a higher number of relapses.

New Tools to Test Stool: Managing Travelers' Diarrhea in the Era of Molecular Diagnostics

Travelers' diarrhea affects up to 60% of visitors to tropical and subtropical regions. Although symptoms are generally self-limited, some infections are associated with significant morbidity and occasional mortality. Newer molecular diagnostic techniques allow for highly sensitive, specific, and expeditious testing of a wide range of potential pathogens. Identification of the causative pathogen of travelers' diarrhea allows for targeted therapy and management and a reduction in empiric broad-spectrum coverage.

Whipple's disease and Tropheryma whipplei infections: when to suspect them and how to diagnose and treat them

PURPOSE OF REVIEW

The delay between first clinical signs and diagnosis of Whipple's disease and Tropheryma whipplei infections is more than 6 years, and relapses are frequently observed, resulting in a need for clinicians to be aware of this infection.

RECENT FINDINGS

18 FDG-PET is useful in the diagnosis and the follow-up of patients (particularly in case of neurological involvement). Histological involvement remains the goldstandard for classic Whipple's disease diagnosis. PCR performed on biopsies of fluid is the main tool for the diagnosis of localized chronic infections. PCR performed on urine samples should become an important role of noninvasive diagnostic strategies, while T. whipplei PCR performed on saliva and stool lack specificity. Because of lifetime susceptibility to T. whipplei and in-vitro susceptibility data, a 1-year course of doxycycline and hydroxychloroquine followed by a lifelong treatment by doxycycline is recommended for Whipple's disease, localized endocarditis and encephalitis.

SUMMARY

Clinical involvement of the different T. whipplei infections is well described, as well as the treatment of Whipple's disease, endocarditis and encephalitis. The place of PCR performed on urine remains to be clarified for diagnosis of localized T. whipplei infections and acute infections as well as the optimal treatment for arthritis and acute infections.

Tropheryma whipplei intestinal colonization in Italian and migrant population: a retrospective observational study

AIM

To obtain the first molecular epidemiological survey of Tropheryma whipplei intestinal colonization in Italy. Materials & methods: Retrospective, observational study to assess the prevalence of T. whipplei, the causative agent of Whipple's disease, in stool samples (real-time PCR) of patients attending the Center for Tropical Diseases (Italy) and risk factors associated.

RESULTS

Overall prevalence was 6.9% (85/1240). The younger age group showed a significantly higher rate than older age group (12.7 vs 5.9%, p = 0.002). The prevalence was 4.9% for Italians and 9.3% for migrants (p = 0.003). Among the latter, children less than 10 years had higher prevalence than older ones (17.3 vs 7.3%, p = 0.003). The young age, male gender and Giardia duodenalis and Entamoeba histolytica coinfection were risk factors.

CONCLUSION

Our study confirms an increased risk of acquiring T. whipplei infection during childhood, under poor sanitary conditions.

Detection of Tropheryma whipplei in stool samples by one commercial and two in-house real-time PCR assays

OBJECTIVE

Tropheryma whipplei, the causative agent of Whipple's disease, can also be identified in stool samples of humans without systemic disease. It is much more frequently detected in human stool samples in tropical environments than in industrialized countries. PCR-screening has been applied for point prevalence studies and environmental assessments in tropical settings, but results depend on the applied assay. We compared one commercial qPCR kit with two well-described in-house assays for detection of T. whipplei from stool.

METHODS

Residual materials from nucleic acid extractions of stool samples from two groups with presumably different prevalences and increased likelihood of being colonized or infected by T. whipplei were tested. One group comprised 300 samples from study participants from western Africa (group 1); the second group was of 300 returnees from tropical deployments (group 2). Each sample was assessed with all three qPCR assays. Cycle threshold (C_t ) values were descriptively compared.

RESULTS

Based solely on mathematical modeling, the three PCR assays showed considerably different detection rates of T. whipplei DNA in stool samples (kappa 0.67 (95% confidence interval [0.60, 0.73])). Considering the calculated test characteristics, prevalence of 28.3% for group 1 and 5.0% for group 2 was estimated. Discordant test results were associated with later C_t values. The study did not validate the assays for the detection of T. whipplei in Whipple's disease and for diagnostic purposes since clinical specificity and sensitivity were not investigated.

CONCLUSIONS

In spite of the observed diagnostic uncertainty, PCR-based screening approaches can be used for epidemiological purposes and environmental samples to define the source and reservoir in resource-limited tropical settings if prevalence is calculated using diagnostic accuracy-adjusted methods.

Tropheryma whipplei Increases Expression of Human Leukocyte Antigen-G on Monocytes to Reduce Tumor Necrosis Factor and Promote Bacterial Replication

BACKGROUND & AIMS

Infection with Tropheryma whipplei has a range of effects-some patients can be chronic carriers without developing any symptoms, whereas others can develop systemic Whipple disease, characterized by a lack a protective inflammatory immune response. Alterations in HLA-G function have been associated with several diseases. We investigated the role of HLA-G during T whipplei infection.

METHODS

Sera, total RNA, and genomic DNA were collected from peripheral blood from 22 patients with classic Whipple's disease, 19 patients with localized T whipplei infections, and 21 asymptomatic carriers. Levels of soluble HLA-G in sera were measured by enzyme-linked immuosorbent assay, and expressions of HLA-G and its isoforms were monitored by real-time polymerase chain reaction. HLA-G alleles were identified and compared with a population of voluntary bone marrow donors. Additionally, monocytes from healthy subjects were stimulated with T whipplei, and HLA-G expression was monitored by real-time polymerase chain reaction and flow cytometry. Bacterial replication was assessed by polymerase chain reaction in the presence of HLA-G or inhibitor of tumor necrosis factor (TNF) (etanercept).

RESULTS

HLA-G mRNAs and levels of soluble HLA-G were significantly increased in sera from patients with chronic T whipplei infection compared with sera from asymptomatic carriers and control individuals. No specific HLA-G haplotypes were associated with disease or T whipplei infection. However, T whipplei infection of monocytes induced expression of HLA-G, which was associated with reduced secretion of TNF compared with noninfected monocytes. A neutralizing antibody against HLA-G increased TNF secretion by monocytes in response to T whipplei, and a TNF inhibitor promoted bacteria replication.

CONCLUSIONS

Levels of HLA-G are increased in sera from patients with T whipplei tissue infections, associated with reduced production of TNF by monocytes. This might promote bacteria colonization in patients.

Tropheryma whipplei as a Cause of Epidemic Fever, Senegal, 2010-2012

Findings suggest that the bacterium has role in febrile episodes, is contagious, and has an epidemic character.

The bacterium Tropheryma whipplei, which causes Whipple disease in humans, is commonly detected in the feces of persons in Africa. It is also associated with acute infections. We investigated the role of T. whipplei in febrile patients from 2 rural villages in Senegal. During June 2010–March 2012, we collected whole-blood finger-prick samples from 786 febrile and 385 healthy villagers. T. whipplei was detected in blood specimens from 36 (4.6%) of the 786 febrile patients and in 1 (0.25%) of the 385 apparently healthy persons. Of the 37 T. whipplei cases, 26 (70.2%) were detected in August 2010. Familial cases and a potential new genotype were observed. The patients’ symptoms were mainly headache (68.9%) and cough (36.1%). Our findings suggest that T. whipplei is a cause of epidemic fever in Senegal.

Clinical Manifestations, Treatment, and Diagnosis of Tropheryma whipplei Infections

Whipple's disease is a rare infectious disease that can be fatal if left untreated. The disease is caused by infection with Tropheryma whipplei, a bacterium that may be more common than was initially assumed. Most patients present with nonspecific symptoms, and as routine cultivation of the bacterium is not feasible, it is difficult to diagnose this infection. On the other hand, due to the generic symptoms, infection with this bacterium is actually quite often in the differential diagnosis. The gold standard for diagnosis used to be periodic acid-Schiff (PAS) staining of duodenal biopsy specimens, but PAS staining has a poor specificity and sensitivity. The development of molecular techniques has resulted in more convenient methods for detecting T. whipplei infections, and this has greatly improved the diagnosis of this often missed infection. In addition, the molecular detection of T. whipplei has resulted in an increase in knowledge about its pathogenicity, and this review gives an overview of the new insights in epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of Tropheryma whipplei infections.

Peripheral T-Cell Reactivity to Heat Shock Protein 70 and Its Cofactor GrpE from Tropheryma whipplei Is Reduced in Patients with Classical Whipple's Disease

Classical Whipple's disease (CWD) is characterized by the lack of specific Th1 response toward Tropheryma whipplei in genetically predisposed individuals. The cofactor GrpE of heat shock protein 70 (Hsp70) from T. whipplei was previously identified as a B-cell antigen. We tested the capacity of Hsp70 and GrpE to elicit specific proinflammatory T-cell responses. Peripheral mononuclear cells from CWD patients and healthy donors were stimulated with T. whipplei lysate or recombinant GrpE or Hsp70 before levels of CD40L, CD69, perforin, granzyme B, CD107a, and gamma interferon (IFN-γ) were determined in T cells by flow cytometry. Upon stimulation with total bacterial lysate or recombinant GrpE or Hsp70 of T. whipplei, the proportions of activated effector CD4⁺ T cells, determined as CD40L⁺ IFN-γ⁺, were significantly lower in patients with CWD than in healthy controls; CD8⁺ T cells of untreated CWD patients revealed an enhanced activation toward unspecific stimulation and T. whipplei-specific degranulation, although CD69⁺ IFN-γ⁺ CD8⁺ T cells were reduced upon stimulation with T. whipplei lysate and recombinant T. whipplei-derived proteins. Hsp70 and its cofactor GrpE are immunogenic in healthy individuals, eliciting effective responses against T. whipplei to control bacterial spreading. The lack of specific T-cell responses against these T. whipplei-derived proteins may contribute to the pathogenesis of CWD.

Genotypic analysis of Tropheryma whipplei from patients with Whipple disease in the Americas

Tropheryma whipplei, the agent of Whipple disease, causes a rare bacterial disease that may be fatal if not treated. The classical form of the disease includes diarrhoea, weight loss, arthritis, endocarditis and neurological manifestations. Genotyping studies done in Europe, Africa and Asia showed high genetic diversity with no correlation between genotypes and clinical features, but contributed to a better understanding of the epidemiology of the disease. More than 70 genotypes have been described. No similar assessment of T. whipplei in the USA and the Caribbean has been performed. In this study, we describe genetic analysis of DNA from histopathological samples obtained from 30 patients from the Americas with Whipple disease and compare the genotypes with those previously identified. Complete genotypes were obtained from 18 patients (60%). Only 4 genotypes were previously described, and 14 were newly reported, confirming the diversity of T. whipplei strains.

Acute infections caused by Tropheryma whipplei

Tropheryma whipplei is the causative bacterium of Whipple's disease. Its first culture has led to an enlargement of the field of the caused infections. Here, we comprehensively review acute T. whipplei infections. In a cohort study featuring 4000 children, T. whipplei was significantly more common in patients with diarrhea (4%) than in those without (1.7%). A case–controlled study highlighted 58 patients suffering from pneumonia with the detection of T. whipplei in their bronchoalveolar fluids. Finally, a recent study detected T. whipplei in the blood of 36 febrile patients experiencing pulmonary symptoms in a rural area of Senegal. T. whipplei is definitively an agent of acute gastroenteritis, a cause of nonmalarial fever in Africa, and probably a cause of pulmonary infections.

Whipple's disease

In recent years, it has become apparent that Tropheryma whipplei not only causes a chronic multisystemic infection which is often preceded by arthropathies for many years, well known as 'classical' Whipple's disease, but also clinically becomes manifest with localized organ affections and acute (transient) infections in children. T. whipplei is found ubiquitously in the environment and colonizes in some healthy carriers. In this review, we highlight new aspects of this enigmatic infectious disorder.

Tropheryma whipplei associated with diarrhoea in young children

Tropheryma whipplei was detected in preliminary studies in faeces of young children with diarrhoea and also in faeces of asymptomatic persons, not only in Europe but also in Africa. In this study, the link between this bacterium and the presence of acute diarrhoea was evaluated in a large group of children. From December 2009 to January 2013, rectal swabs collected from 3796 children in the emergency departments of university hospitals in Marseille, France, were analysed: 555 children (245 female and 310 male, from 6 days to 6 years old) with acute diarrhoea defined as at least three loose stools per day for <1 week and 3241 children (1444 female and 1797 male, from 22 days to 6 years old) without diarrhoea. Specific quantitative real-time PCR was performed to detect the presence of T. whipplei and of two enteric pathogens Clostridium difficile and Giardia duodenalis. Tropheryma whipplei was significantly more common in children with diarrhoea (22/555, 4%) than without (56/3241, 1.7%; p 0.001). Neither C. difficile nor G. duodenalis showed this association. For C. difficile, 39 of 531 (7.3%) children with diarrhoea were positive versus 184 of 3119 (5.9%) of children without diarrhoea (p 0.25). For G. duodenalis, 2 of 529 (0.37%) children with diarrhoea were positive versus 5 of 3119 (0.16%) children without diarrhoea (p 0.26). Tropheryma whipplei was found more commonly in autumn. Tropheryma whipplei is significantly associated with diarrhoea in children, suggesting that the bacterium may be a cause of acute diarrhoea.

Tropheryma whipplei infection and Whipple's disease

Recent advances in medical microbiology, epidemiology, cellular biology, and the availability of an expanded set of diagnostic methods such as histopathology, immunohistochemistry, PCR, and bacterial culture have improved our understanding of the clinical range and natural course of Tropheryma whipplei infection and Whipple's disease. Interdisciplinary and transnational research activities have contributed to the clarification of the pathogenesis of the disorder and have enabled controlled trials of different treatment strategies. We summarise the current knowledge and new findings relating to T whipplei infection and Whipple's disease.

High prevalence of asymptomatic carriers of Tropheryma whipplei in different populations from the North of Spain

INTRODUCTION

Tropheryma whipplei is the causative agent of Whipple disease. T. whipplei has also been detected in asymptomatic carriers with a very different prevalence. To date, in Spain, there are no data regarding the prevalence of T. whipplei in a healthy population or in HIV-positive patients, or in chronic fatigue syndrome (CFS). Therefore, the aim of this work was to assess the prevalence of T. whipplei in stools in those populations.

METHODS

Stools from 21 HIV-negative subjects, 65 HIV-infected, and 12 CFS patients were analysed using real time-PCR. HIV-negative and positive subjects were divided into two groups, depending on the presence/absence of metabolic syndrome (MS). Positive samples were sequenced.

RESULTS

The prevalence of T. whipplei was 25.51% in 98 stool samples analysed. Prevalence in HIV-positive patients was significantly higher than in HIV-negative (33.8% vs. 9.09%, p=0.008). Prevalence in the control group with no associated diseases was 20%, whereas no positive samples were observed in HIV-negative patients with MS, or in those diagnosed with CFS. The prevalence observed in HIV-positive patients without MS was 30.35%, and with MS it was 55.5%. The number of positive samples varies depending on the primers used, although no statistically significant differences were observed.

CONCLUSIONS

There is a high prevalence of asymptomatic carriers of T. whipplei among healthy and in HIV-infected people from Spain. The role of T. whipplei in HIV patients with MS is unclear, but the prevalence is higher than in other populations.

Tropheryma whipplei in children with diarrhoea in rural Ghana

Tropheryma whipplei has been hypothesized to be able to cause diarrhoea, but data from young children are scarce. In this hospital-based case-control study 534 stool samples of children aged between 2 months and 15 years from rural Ghana were analysed for the presence of T. whipplei. Overall stool prevalence of T. whipplei was high (27.5%). Although there was no difference in T. whipplei carriage overall between cases and controls, cases aged between 0 and 12 months carried T. whipplei in their stool twice as often as controls without diarrhoea. The results from this study may support the hypothesis that T. whipplei can cause diarrhoea in first-time infection.

Whipple's Disease

Background

Whipple's disease (WD) is rarely the cause of a malabsorption syndrome. The disease is a chronic infection of the intestinal mucosa with the bacterium Tropheryma whipplei, which leads to a lymphostasis with an impaired absorption of the nutrition. Due to its low incidence (1:1,000,000) and the non-specific early symptoms, the disease is often diagnosed only after many years.

Methods

Based on a selective literature review and the clinical experience of the authors, the current knowledge of WD regarding pathogenesis, clinical presentation, diagnosis, and therapy are presented in this paper.

Results

Recent studies suggest that a host-specific dysfunction of the intestinal macrophages is responsible for the chronic infection with T. whipplei. Prior to patients reporting symptoms of a malabsorption syndrome (chronic diarrhea/steatorhea, weight loss), they often suffer from non-specific symptoms (polyarthralgia, fever, fatigue) for many years. Misdiagnoses such as seronegative polyarthritis are frequent. Furthermore, neurological, cardiac, ocular, or dermatological symptoms may occur. The standard method concerning diagnosis is the detection of PAS(periodic acid-Schiff)-positive macrophages in the affected tissues. Immunohistochemical staining and PCR(polymerase chain reaction)-based genetic analysis increase the sensitivity and specificity of conventional detection methods. Endoscopically, the intestinal mucosa appears edematous with lymphangiectasias, enlarged villi, and white-yellowish ring-like structures. The German treatment recommendations include a two-week intravenous induction therapy with ceftriaxone, which is followed by a three-month oral maintenance therapy with trimethoprim/sulfamethoxazole.

Conclusion

WD is rarely responsible for a malabsorption syndrome. However, if WD is not recognized, the disease can be lethal. New diagnostic methods and prospectively approved therapeutic concepts allow an adequate treatment of the patient. Due to the host-specific susceptibility to T. whipplei, a lifelong follow-up is necessary.

Prevalence and risk factor assessment of Tropheryma whipplei in a rural community in Gabon: a community-based cross-sectional study

Tropheryma whipplei is the causative agent of Whipple's disease and has been detected in stools of asymptomatic carriers. Colonization has been associated with precarious hygienic conditions. There is a lack of knowledge about the epidemiology and transmission characteristics on a population level, so the aim of this study was to determine the overall and age-specific prevalence of T. whipplei and to identify risk factors for colonization. This molecular epidemiological survey was designed as a cross-sectional study in a rural community in Central African Gabon and inhabitants of the entire community were invited to participate. Overall prevalence assessed by real-time PCR and sequencing was 19.6% (95% CI 16-23.2%, n=91) in 465 stool samples provided by the study participants. Younger age groups showed a significantly higher prevalence of T. whipplei colonization ranging from 40.0% (95% CI 27.8-52.2) among the 0-4 year olds to 36.4% (95% CI 26.1-46.6) among children aged 5-10 years. Prevalence decreased in older age groups (p<0.001) from 12.6% (95% CI 5.8-19.4%; 11-20 years) to 9.7% (95% CI 5.7-13.6) among those older than 20. Risk factor analysis revealed young age, male sex, and number of people sharing a bed as factors associated with an increased risk for T. whipplei carriage. These results demonstrate that T. whipplei carriage is highly prevalent in this part of Africa. The high prevalence in early life and the analysis of risk factors suggest that transmission may peak during childhood facilitated through close person-to-person contacts.

Clostridium butyricum Strains and Dysbiosis Linked to Necrotizing Enterocolitis in Preterm Neonates

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common and serious gastrointestinal disorder among preterm neonates. We aimed to assess a specific gut microbiota profile associated with NEC.

METHODS

Stool samples and clinical data were collected from 4 geographically independent neonatal intensive care units, over a 48-month period. Thirty stool samples from preterm neonates with NEC (n = 15) and controls (n = 15) were analyzed by 16S ribosomal RNA pyrosequencing and culture-based methods. The results led us to develop a specific quantitative polymerase chain reaction (qPCR) assay for Clostridium butyricum, and we tested stool samples from preterm neonates with NEC (n = 93) and controls (n = 270). We sequenced the whole genome of 16 C. butyricum strains, analyzed their phylogenetic relatedness, tested their culture supernatants for cytotoxic activity, and searched for secreted toxins.

RESULTS

Clostridium butyricum was specifically associated with NEC using molecular and culture-based methods (15/15 vs 2/15; P < .0001) or qPCR (odds ratio, 45.4 [95% confidence interval, 26.2-78.6]; P < .0001). Culture supernatants of C. butyricum strains from preterm neonates with NEC (n = 14) exhibited significant cytotoxic activity (P = .008), and we identified in all a homologue of the β-hemolysin toxin gene shared by Brachyspira hyodysenteriae, the etiologic agent of swine dysentery. The corresponding protein was secreted by a NEC-associated C. butyricum strain.

CONCLUSIONS

NEC was associated with C. butyricum strains and dysbiosis with an oxidized, acid, and poorly diversified gut microbiota. Our findings highlight the plausible toxigenic mechanism involved in the pathogenesis of NEC.

Gastrointestinal diagnosis of classical Whipple disease: clinical, endoscopic, and histopathologic features in 191 patients

Classic Whipple disease (CWD) is a systemic infection caused by Tropheryma whipplei. Different diagnostic tools have been developed over the last decades: periodic acid-Schiff (PAS) staining, T whipplei-specific polymerase chain reaction (PCR), and T whipplei-specific immunohistochemistry (IHC). Despite all these advances, CWD is still difficult to diagnose because of a variety of clinical symptoms and possibly a long time span between first unspecific symptoms and the full-blown clinical picture of the disease. Herein, we report an observational cohort study summarizing epidemiologic data, clinical manifestations, and diagnostic parameters of 191 patients with CWD collected at our institution. Gastrointestinal manifestations are the most characteristic symptoms of CWD affecting 76% of the cohort. Although the small bowel was macroscopically conspicuous in only 27% of cases, 173 (91%) patients presented with characteristic histological changes in small bowel biopsies (in 2 patients, these changes were only seen within the ileum). However, 18 patients displayed normal small bowel histology without typical PAS staining. In 9 of these patients, alternative test were positive from their duodenal specimens (ie, T whipplei-specific PCR and/or IHC). Thus, in 182 patients (95%) a diagnostic hint toward CWD was obtained from small bowel biopsies. Only 9 patients (5%) were diagnosed solely based on positive T whipplei-specific PCR and/or IHC of extraintestinal fluids (eg, cerebrospinal fluid, synovial fluid) or extraintestinal tissue (eg, lymph node, synovial tissue), respectively. Thus, despite efforts to diagnose CWD from alternative specimens, gastroscopy with duodenal biopsy and subsequent histological and molecular-biological examination is the most reliable diagnostic tool for CWD.

Systematic review: Whipple's disease (Tropheryma whipplei infection) and its unmasking by tumour necrosis factor inhibitors

BACKGROUND

The classical form of Whipple's disease (WD), clinically characterised by arthropathy, diarrhoea and weight loss, is rare. Recently, other more frequent forms of Tropheryma whipplei infection have been recognised. The clinical spectrum includes an acute, self-limiting disease in children, localised forms affecting cardiac valves or the central nervous system without intestinal symptoms, and asymptomatic carriage of T. whipplei which is found in around 4% of Europeans. Genomic analysis has shown that T. whipplei represents a host-dependent or opportunistic bacterium. It has been reported that the clinical course of T. whipplei infection may be influenced by medical immunosuppression.

AIM

To identify associations between immunomodulatory treatment and the clinical course of T. whipplei infection.

METHODS

A PubMed literature search was performed and 19 studies reporting on immunosuppression, particularly therapy with tumour necrosis factor inhibitors (TNFI) prior to the diagnosis in 41 patients with Whipple?s disease, were evaluated.

RESULTS

As arthritis may precede the diagnosis of WD by many years, a relevant percentage (up to 50% in some reports) of patients are treated with immunomodulatory drugs or with TNFI. Many publications report on a complicated Whipple?s disease course or T. whipplei endocarditis following medical immunosuppression, particularly after TNFI. Standard diagnostic tests such as periodic acid-Schiff stain used to diagnose Whipple?s disease often fail in patients who are pre-treated by TNFI.

CONCLUSIONS

In cases of doubt, Whipple?s disease should be excluded before therapy with TNFI. The fact that immunosuppressive therapy contributes to the progression of T. whipplei infection expands our pathogenetic view of this clinical entity.

Chronic infections of the small intestine

PURPOSE OF REVIEW

Chronic infections of the small intestine cause significant morbidity and mortality globally. This review focuses on the recent advances in the field of our understanding of selected intestinal infections.

RECENT FINDINGS

Primary and secondary immunodeficiency increase the susceptibility to many chronic intestinal infections. Endoscopy and intestinal biopsies are central to establishing a diagnosis of these conditions. Tuberculosis (TB) remains a major global health challenge. Emerging therapeutic agents to counteract multidrug-resistant strains have shown clinical efficacy, but concerns regarding mortality remain. PCR-based diagnostic TB tests have the potential to reduce diagnostic delays, but remain to be validated for intestinal infections. Adjunctive diagnostic imaging modalities can differentiate infections from Crohn's disease with increasing accuracy. Whipple's disease remains rare, but there have been substantial advances in our understanding of the causative organism Tropheryma whipplei. Extended treatment with broad-spectrum antibiotics is effective in most cases. The narrow therapeutic window and limited armamentarium for treating invasive filamentous fungal infections contribute to their significant morbidity and high rates of mortality.

SUMMARY

The speed and accuracy of diagnosing chronic intestinal infections have improved with recent imaging and laboratory methodologies. Significant research opportunities remain for clinicians and scientists to improve the diagnostic accuracy and clinical outcomes of chronic intestinal infections.

High prevalence of Tropheryma whipplei in Lao kindergarten children

Background

Tropheryma whipplei is a bacterium commonly found in feces of young children in Africa, but with no data from Asia. We estimated the prevalence of T. whipplei carriage in feces of children in Lao PDR (Laos).

Methods/Principal Findings

Using specific quantitative real-time PCR, followed by genotyping for each positive specimen, we estimated the prevalence of T. whipplei in 113 feces from 106 children in Vientiane, the Lao PDR (Laos). T. whipplei was detected in 48% (51/106) of children. Those aged ≤4 years were significantly less frequently positive (17/52, 33%) than older children (34/54, 63%; p< 0.001). Positive samples were genotyped. Eight genotypes were detected including 7 specific to Laos. Genotype 2, previously detected in Europe, was circulating (21% of positive children) in 2 kindergartens (Chompet and Akad). Genotypes 136 and 138 were specific to Chompet (21% and 15.8%, respectively) whereas genotype 139 was specific to Akad (10.55%).

Conclusions/Significance

T. whipplei is a widely distributed bacterium, highly prevalent in feces of healthy children in Laos. Further research is needed to identify the public health significance of this finding.

Tropheryma whipplei is a common bacterium carried in feces of young children. Here, using specific PCR, we estimated the prevalence of T. whipplei in 113 feces from 106 children in Vientiane, the Lao PDR (Laos). T. whipplei was detected in 48% (51/106) of children. Eight genotypes were detected, including 7 specific to Laos. Genotype 2, previously detected in Europe, was circulating (21% of positive children) in 2 kindergartens (Chompet and Akad). Genotypes 136 and 138 were specific to Chompet (21% and 15.8%, respectively), whereas genotype 139 was specific to Akad (10.55%). Long regarded as a rare bacterium, now we can affirm that T. whipplei is a widely distributed bacterium, highly prevalent in feces including those from children in Vientiane.

Role of dendritic cells in the pathogenesis of Whipple's disease

Accumulation of Tropheryma whipplei-stuffed macrophages in the duodenum, impaired T. whipplei-specific Th1 responses, and weak secretion of interleukin-12 (IL-12) are hallmarks of classical Whipple's disease (CWD). This study addresses dendritic cell (DC) functionality during CWD. We documented composition, distribution, and functionality of DC ex vivo or after in vitro maturation by fluorescence-activated cell sorting (FACS) and by immunohistochemistry in situ. A decrease in peripheral DC of untreated CWD patients compared to healthy donors was due to reduced CD11c(high) myeloid DC (M-DC). Decreased maturation markers CD83, CD86, and CCR7, as well as low IL-12 production in response to stimulation, disclosed an immature M-DC phenotype. In vitro-generated monocyte-derived DC from CWD patients showed normal maturation and T cell-stimulatory capacity under proinflammatory conditions but produced less IL-12 and failed to activate T. whipplei-specific Th1 cells. In duodenal and lymphoid tissues, T. whipplei was found within immature DC-SIGN(+) DC. DC and proliferating lymphocytes were reduced in lymph nodes of CWD patients compared to levels in controls. Our results indicate that dysfunctional IL-12 production by DC provides suboptimal conditions for priming of T. whipplei-specific T cells during CWD and that immature DC carrying T. whipplei contribute to the dissemination of the bacterium.

An update on travelers' diarrhea

PURPOSE OF REVIEW

Travelers' diarrhea, affecting millions of travelers every year globally, continues to be a leading cause of morbidity despite advances in vaccination, prevention, and treatment. Complications of travelers' diarrhea often present to gastroenterologists and some patients followed by gastroenterologists are at higher risk of developing travelers' diarrhea. This review will provide an update on recent progress made in the epidemiology, pathogenesis, diagnosis, prevention, and treatment of travelers' diarrhea.

RECENT FINDINGS

Most causes of travelers' diarrhea remain bacterial, but newly recognized pathogens are emerging. Patient-related and travel-related factors affect disease development risk and should guide prophylaxis and treatment. Although specific vaccines are being developed, they have not yet had a major impact on travelers' diarrhea, and understanding their roles and limitations is especially important. Prophylaxis and treatment of populations at risk (children, chronically ill patients, and those on immunosuppressive medications) remain challenging and require a tailored approach.

SUMMARY

Travelers' diarrhea will continue to challenge patients and physicians despite the use of sanitation advice, prophylactic vaccines, and treatment with antibiotics. Effects may extend beyond the time of travel, such as postinfectious complications and exacerbation of preexisting disease. Future research should focus on novel strategies for reducing exposure to pathogens, vaccine development, early detection, and targeted treatments.

Complicated Whipple’s disease and endocarditis following tumor necrosis factor inhibitors

AIM: To test whether treatment with tumor necrosis factor inhibitors (TNFI) is associated with complications of Tropheryma whipplei (T. whipplei) infection.

METHODS: Because unexplained arthritis is often the first Whipple’s disease (WD) symptom, patients may undergo treatment with TNFI before diagnosis. This may influence the course of infection with T. whipplei, which causes WD, because host immune defects contribute to the pathogenesis of WD. A literature search and cross referencing identified 19 reports of TNFI treatment prior to WD diagnosis. This case-control study compared clinical data in patients receiving TNFI therapy (group I, n = 41) with patients not receiving TNFI therapy (group II, n = 61). Patients from large reviews served as controls (group III, n = 1059).

RESULTS: The rate of endocarditis in patient group I was significantly higher than in patient group II (12.2% in group I vs 1.6% in group II, P < 0.05), and group III (12.2% in group I vs 0.16% in group III, P < 0.01). Other, severe systemic or local WD complications such as pericarditis, fever or specific organ manifestations were increased also in group I as compared to the other patient groups. However, diarrhea and weight loss were somewhat less frequent in patient group I. WD is typically diagnosed with duodenal biopsy and periodic acid Schiff (PAS) staining. PAS-stain as standard diagnostic test had a very high percentage of false negative results (diagnostic failure in 63.6% of cases) in group I. Polymerase chain reaction (PCR) for T. whipplei was more accurate than PAS-stainings (diagnostic accuracy, rate of true positive tests 90.9% for PCR vs 36.4% for PAS, P < 0.01).

CONCLUSION: TNFI trigger severe WD complications, particularly endocarditis, and lead to false-negative PAS-tests. In case of TNFI treatment failure, infection with T. whipplei should be considered.

[Drug therapy of infectious diarrhea. Part 2: Chronic diarrhea]

Diarrheal diseases are among the most common diseases worldwide. In this review the current treatment recommendations for acute (Part 1) and chronic (Part 2) infectious diarrhea are summarized and typical enteropathogens are discussed. The second part of the article describes chronic diarrhea, its related pathogens and treatment. In contrast to acute diarrhea which is mainly caused by viral and typical bacterial pathogens, chronic diarrhea has mainly non-infectious origins. Protozoal pathogens, such as Giardia lamblia and Entamoeba histolytica in particular are found and more rarely bacterial pathogens, such as Tropheryma whipplei. Opportunistic pathogens cause diarrhea in immunocompromised patients, such as in HIV patients. In these patients cytomegalovirus (CMV) colitis or infections with Cryptosporidium spp., Cyclospora cayetanensis, Isospora belli or microsporidia have to be considered. Besides targeted specific antimicrobial therapy, anti-retroviral drugs improving the underlying immunosuppression and thus the reconstitution of the adaptive immune response remain a cornerstone of the treatment in HIV-positive patients.