First isolation of Tropheryma whipplei from bronchoalveolar fluid and clinical implications

Tropheryma whipplei pneumonia revealed by Metagenomic next-generation sequencing: Report of two cases

Tropheryma whipplei is the causative agent of Whipple's disease, which is a rare multiorgan systemic disease. We report two cases of Tropheryma whipplei infection, all routine tests were negative and it was finally detected by mNGS. This may help clinicians increase awareness of the diagnosis and treatment of acute severe pneumonia and interstitial pneumonia caused by Tropheryma whipplei.

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.

Clinical, Laboratory, and Imaging Characteristics of Tropheryma Whipplei Detection in Bronchoalveolar Lavage Fluid Using Next-Generation Sequencing: A Case-Control Study

Objective

The aim of this study was to assess the prevalence of Tropheryma whipplei (TW) infection in the population and to investigate the clinical symptoms, as well as the laboratory and imaging characteristics of patients testing positive for TW using next-generation sequencing (NGS).

Methods

A retrospective review was conducted on 1346 bronchoalveolar lavage fluid (BALF) samples collected between January 2021 and September 2023. The case group comprised patients with TW detected using NGS while the control group included 65 randomly chosen Gram-positive bacterial infection patients without TW. Comparative analyses were carried out on the basic demographics, laboratory parameters, and imaging findings between the two groups. Additionally, the case group underwent an in-depth examination of underlying diseases, pathogens, final diagnoses, treatment strategies.

Results

The case group comprised of 51 patients with TW, constituting 3.8% of the total. There was no significant difference in gender and age between the case and control groups (P = 0.84, P = 0.07). Symptoms such as coughing, expectoration, wheezing, fever, and hemoptysis are less commonly detected in the case group with a higher incidence of chest pain when compared to the control group (P >0.05). The case group exhibited decreased albumin levels and increased C-reactive protein and D-dimer levels compared to normal levels. Imaging findings in the case group commonly included nodules, patchy images, and interstitial changes, the most common underlying disease is cardiovascular disease, and the most frequently co-occurring pathogen is the human herpesvirus. Among the case group, 27 patients received a final diagnosis of pneumonia, and 3 patients clinically diagnosed with Whipple's disease demonstrated improvement in both symptoms and imaging after treatment.

Conclusion

NGS revealed a relatively low overall detection rate of TW-positive patients using BALF. TW was more prevalent in middle-aged and elderly male patients characterized by symptoms such as cough, expectoration, shortness of breath, and fever. Chest imaging in these cases typically showed nodules and interstitial changes.

Using Targeted Next-Generation Sequencing to Diagnose Severe Pneumonia Due to Tropheryma Whipplei and Human Metapneumovirus: A Case Report and Literature Review

Background

In addition to the well-known Whipple's disease (WD), Tropheryma Whipplei (TW) can also lead to acute pneumonia. There is no unified consensus on the susceptible population, pathogenesis, clinical manifestations, diagnostic criteria, and treatment options for TW pneumonia.

Clinical Presentation and Intervention

This is an elderly patient with multiple injuries caused by falling from a building, and was transferred to intensive care unit (ICU) for mechanical ventilation and empirical anti-infection treatment due to severe pneumonia, and then the results of targeted next-generation sequencing (tNGS) in patient's bronchoalveolar lavage fluid (BALF) suggested TW and human metapneumovirus (HMPV) infection, and after switching to anti-infective therapy for TW, the patient was successfully extubated and transferred out of the ICU.

Conclusion

This is the first case of using tNGS to diagnose severe pneumonia caused by TW and HMPV. We hope that our study can serve as a reference for the diagnosis and treatment of related cases in the future.

Novel Patterns in High-Resolution Computed Tomography in Whipple Pneumonia

With the use of metagenomic next-generation sequencing, patients diagnosed with Whipple pneumonia are being increasingly correctly diagnosed. We report a series of 3 cases in China that showed a novel pattern of movable infiltrates and upper lung micronodules. After treatment, the 3 patients recovered, and lung infiltrates resolved.

Co-infection of Chlamydia psittaci and Tropheryma whipplei: A case report

BACKGROUND

The co-infection of Chlamydia psittaci (C. psittaci) and Tropheryma whipplei (T. whipplei) is unusual, and the detection of pathogenic microorganisms is particularly important for patients with severe diseases or poor experience in treatment. Early identification of pathogens can significantly improve the prognosis of the patients. Targeted next-generation sequencing (tNGS) is currently widely used in clinical practice for various infectious diseases, including respiratory infections, to achieve early, accurate, and rapid microbial diagnosis.

CASE SUMMARY

We report a case of a 40-year-old female patient with a history of contact with parrots who was diagnosed with C. psittaci and T. whipplei infection through bronchial lavage fluid targeted next generation sequencing. After moxifloxacin treatment, the patient's symptoms improved significantly, and the imaging changes were obviously resolved.

CONCLUSION

Coinfection with C. psittaci and T. whipplei is not common. In this case, timely and accurate identification of both pathogens was achieved using tNGS. Moreover, the efficacy of monotherapy with moxifloxacin was confirmed.

Tropheryma whipplei-induced plastic bronchitis in children: a case report

This article reports a case of a 7-year-old child with severe pneumonia whose chest CT showed pulmonary consolidation, and bronchoscopy revealed plastic bronchitis. The metagenomic Next-Generation Sequencing (NGS) of the pulmonary lavage fluid suggested the infection of Tropheryma whipplei (T whipplei). The patient was treated with bronchial lavage to remove sputum plugs, intravenous azithromycin, and piperacillin-tazobactam and was discharged after eight days of hospitalization without any recurrence during follow-up. This article aims to raise clinical awareness of T whipplei infection and suggests that NGS for rare pathogens should be performed early for unexplained plastic bronchitis.

Experience in the diagnosis and treatment of pneumonia caused by infection with Tropheryma whipplei: A case series

Tropheryma whipplei (TW) is the root cause of Whipple's disease (WD), a rare infectious illness leading to multi-organ impairment. A prominent feature of WD is acute pneumonia, which can be exceedingly challenging to diagnose clinically due to the pathogen's surreptitious nature. However and significantly, with the advent of metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF), it offers clinicians a potent tool at their disposal to detect TW infections. The present study conducted a retrospective analysis of clinical data gleaned from five patients in Hunan Province in China. Findings in this study demonstrated the potential of BALF-mNGS in diagnosing pneumonia caused by TW infection.

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 detection by metagenomic next-generation sequencing in bronchoalveolar lavage fluid: A cross-sectional study

Tropheryma whipplei is the bacterium associated with Whipple’s disease (WD), a chronic systemic infectious disease primarily involving the gastrointestinal tract. T. whipplei can also be detected in different body site of healthy individuals, including saliva and feces. Traditionally, Tropheryma whipplei has a higher prevalence in bronchoalveolar lavage fluid (BALF) of immunocompromised individuals. Few studies have explored the significance of the detection of T. whipplei in BALF. Herein, we retrospectively reviewed 1725 BALF samples which detected for metagenomic next-generation sequencing (mNGS) from March 2019 to April 2022 in Zhuhai, China. Seventy BALs (70/1725, 4.0%) from 70 patients were positive for T. whipplei. Forty-four patients were male with an average age of 50 years. The main symptoms included cough (23/70), expectoration (13/70), weight loss (9/70), and/or dyspnea (8/70), but gastrointestinal symptoms were rare. Chronic liver diseases were the most common comorbidity (n=15, 21.4%), followed by diabetes mellitus (n=13, 18.6%). Only nine patients (12.9%) were immunocompromised. Twenty-four patients (34.3%) were finally diagnosed with reactivation tuberculosis and 15 patients (21.4%) were diagnosed with lung tumors, including 13 primary lung adenocarcinoma and two lung metastases. Fifteen patients (21.4%) had pneumonia. Among the 20 samples, T. whipplei was the sole agent, and Mycobacterium tuberculosis complex was the most common detected other pathogens. Among the non-tuberculosis patients, 31 (31/46, 67.4%) had ground glass nodules or solid nodules on chest CT. Our study indicates that T. whipplei should be considered as a potential contributing factor in some lung diseases. For non-immunocompromised patients, the detection of T. whipplei also needs attention. The mNGS technology improves the detection and attention of rare pathogens. In the future, the infection, colonization, and prognosis of T. whipplei in lung still need to be studied.

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 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.

Case Report: Tropheryma whipplei Hide in an AIDS Patient With Pneumocystis Pneumonia

Introduction: Pneumocystis pneumonia (PCP) is one of the most common opportunistic infections in HIV-infected patients. However, coinfection with Tropheryma whipplei is infrequent in AIDS patients with PCP. Case Presentation: We report a 28-year-old male AIDS patient coinfected with T. whipplei and Pneumocystis jirovecii diagnosed in the bronchoalveolar lavage. After sulfamethoxazole-trimethoprim and meropenem treatment, the patient showed clinical improvement in 2 weeks. Conclusion: Clinicians need to be alert to the occurrence of T. whipplei infection in AIDS patients with PCP and timely diagnosis and antibacterial treatments are essential. This case may help clinicians for timely diagnosis of the coinfection of T. whipplei and P. jirovecii in AIDS patients.

Pulmonary parenchymal involvement caused by Tropheryma whipplei

We report a 26-year-old man with left chest pain for 4 days. His chest CT showed a cavity in the left upper lung. Tuberculosis was suspected first, but metagenomics next generation sequencing (mNGS) in bronchoalveolar lavage fluid only detected Tropheryma whipplei. Tropheryma whipplei is the pathogen of Whipple’s disease. The most frequently involved organs are the eyes, heart, and central nervous system. Pulmonary parenchymal involvement is rare. To our knowledge, this is the first reported case of pulmonary cavity caused by Tropheryma whipplei. Nineteen cases of pulmonary parenchymal involvement were found by literature search. The most common respiratory symptom was cough, followed by dyspnea/breathlessness and chest pain. The most common finding in chest imaging was pulmonary nodules, followed by interstitial changes and patchy infiltration. Our case and literature review highlighted that Tropheryma whipplei infection should be considered in the differential diagnosis of pulmonary cavity, pulmonary nodules, interstitial changes, and patchy infiltration. mNGS is helpful to improve diagnosis rate.

Severe pneumonia in adults caused by Tropheryma whipplei and Candida sp. infection: a 2019 case series

Background

Whipple’s disease is a chronic infectious disease caused by the Gram-positive bacterium Tropheryma whipplei (TW), which not only affects the gastrointestinal tract and causes malabsorption of nutrients, but several other systems, such as the cardiovascular system, central nervous system, the joints, and the vascular system, can also be simultaneously involved. The aim of this report was to be able to alert the clinician to severe pneumonia caused by TW combined with Candida sp.

Case presentation

The case study was conducted on patients in September and November 2019. After routine examination and treatment, the results were not satisfactory. A bronchoalveolar lavage (BAL) using metagenomics next-generation sequencing was conducted on two adults who presented with fever, cough, and progressive dyspnea and who had no history of gastrointestinal symptoms, immunodeficiency diseases, or use of immunosuppressive agents. TW and Candida sp. were detected in in BAL.

Conclusions

This is a report of life-threatening pneumonia caused by TW combined with Candida sp. in a Chinese population.

Comprehensive evaluation of complex polymicrobial specimens using next generation sequencing and standard microbiological culture

Optimal clinical decision-making depends on identification of clinically relevant organisms present in a sample. Standard microbiological culture may fail to identify unusual or fastidious organisms and can misrepresent relative abundance of sample constituents. Culture-independent methods have improved our ability to deconvolute polymicrobial patient samples. We used next-generation 16S rRNA gene sequencing (NGS16S) to determine how often cultivatable organisms in complex polymicrobial samples are not reported by standard culture. Twenty consecutive bronchoalveolar lavage (BAL) samples were plated to standard and additional media; bacteria were identified by NGS16S analysis of DNA extracted directly from samples or from washed culture plates. 96% of organisms identified were cultivable, but only 21% were reported by standard culture, indicating that standard work-up provides an incomplete assessment of microbial constituents. Direct NGS16S correlated well with standard culture, identifying the same predominant organism in 50% of samples. When predominant organisms differed, NGS16S most often detected anaerobes, whose growth is unsupported by standard culture conditions for this specimen. NGS16S identified more organisms per sample and allowed identification of fastidious organisms, while culture was better at capturing organisms when bacterial load was low, and allowed incidental recovery of non-bacterial pathogens. Molecular and culture-based methods together detect more organisms than either method alone.

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.

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.

Atypical bacterial pneumonia in the HIV-infected population

Human immunodeficiency virus (HIV)-infected individuals are more susceptible to respiratory tract infections by other infectious agents (viruses, bacteria, parasites, and fungi) as their disease progresses to acquired immunodeficiency syndrome. Despite effective antiretroviral therapy, bacterial pneumonia (the most frequently occurring HIV-associated pulmonary illness) remains a common cause of morbidity and mortality in the HIV-infected population. Over the last few decades, studies have looked at the role of atypical bacterial pneumonia (i.e. pneumonia that causes an atypical clinical presentation or responds differently to typical therapeutics) in association with HIV infection. Due to the lack of available diagnostic strategies, the lack of consideration, and the declining immunity of the patient, HIV co-infections with atypical bacteria are currently believed to be underreported. Thus, following an extensive database search, this review aimed to highlight the current knowledge and gaps regarding atypical bacterial pneumonia in HIV. The authors discuss the prevalence of Chlamydophila pneumoniae, Mycoplasma pneumoniae, Coxiella burnetii, Legionella species and others in the HIV-infected population as well as their clinical presentation, methods of detection, and treatment. Further studies looking at the role of these microbes in association with HIV are required. Increased knowledge of these atypical bacteria will lead to a more rapid diagnosis of these infections, resulting in an improved quality of life for the HIV-infected population.

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.

Airway dysbiosis: Haemophilus influenzae and Tropheryma in poorly controlled asthma

Asthma is a chronic inflammatory disorder of the airways where bacteria may act as protagonists of chronic inflammation. Little is known about the relation of airway inflammation to the presence of specific bacterial taxa. We sought to describe the sputum microbiome in adults with poorly controlled asthma.DNA was extracted from induced sputum and microbial communities were profiled using 16S rRNA pyrosequencing. Bacterial species were characterised, and the relationship between microbial populations, asthma inflammatory subtypes and other covariates was explored. Real-time PCR was used to identify Tropheryma whipplei and Haemophilus influenzae in sputum.Adults with neutrophilic asthma had reduced bacterial diversity and species richness. Tropheryma was identified and confirmed with real-time PCR in 12 (40%) participants. Haemophilus occurred most often in a group of younger atopic males with an increased proportion of neutrophils. PCR confirmed the presence of H. influenzae in 35 (76%) participants with poorly controlled asthma.There are phenotype-specific alterations to the airway microbiome in asthma. Reduced bacterial diversity combined with a high prevalence of H. influenzae was observed in neutrophilic asthma, whereas eosinophilic asthma had abundant T. whipplei.

Current and past strategies for bacterial culture in clinical microbiology

A pure bacterial culture remains essential for the study of its virulence, its antibiotic susceptibility, and its genome sequence in order to facilitate the understanding and treatment of caused diseases. The first culture conditions empirically varied incubation time, nutrients, atmosphere, and temperature; culture was then gradually abandoned in favor of molecular methods. The rebirth of culture in clinical microbiology was prompted by microbiologists specializing in intracellular bacteria. The shell vial procedure allowed the culture of new species of Rickettsia. The design of axenic media for growing fastidious bacteria such as Tropheryma whipplei and Coxiella burnetii and the ability of amoebal coculture to discover new bacteria constituted major advances. Strong efforts associating optimized culture media, detection methods, and a microaerophilic atmosphere allowed a dramatic decrease of the time of Mycobacterium tuberculosis culture. The use of a new versatile medium allowed an extension of the repertoire of archaea. Finally, to optimize the culture of anaerobes in routine bacteriology laboratories, the addition of antioxidants in culture media under an aerobic atmosphere allowed the growth of strictly anaerobic species. Nevertheless, among usual bacterial pathogens, the development of axenic media for the culture of Treponema pallidum or Mycobacterium leprae remains an important challenge that the patience and innovations of cultivators will enable them to overcome.

Tropheryma whipplei as a commensal bacterium

Tropheryma whipplei is the bacterial agent of the well-known and rare Whipple's disease, mainly observed among Caucasians. This bacterium has recently been involved in other chronic and acute infections. For a long time, the only known source of the bacterium was patients with Whipple's disease; however, thanks to the advent of molecular biology, T. whipplei has now been detected in specimens from healthy individuals, mainly in stool and saliva samples. The prevalence of carriage depends on several factors, such as age, exposure and geographical area, reaching 75% in stool specimens from children less than 4 years old in rural Africa. T. whipplei is a commensal bacterium that only causes Whipple's disease in a subset of individuals, probably those with a still-uncharacterized specific immunological defect.

Looking for Tropheryma whipplei source and reservoir in rural Senegal

Tropheryma whipplei, the bacterium linked to Whipple's disease, is involved in acute infections and asymptomatic carriage. In rural Senegal, the prevalence of T. whipplei is generally high but is not homogeneous throughout households in the same village. We studied environmental samples collected in two Senegalese villages and conducted the survey to investigate the difference between households. Overall, the comparison between five households with very high T. whipplei prevalence and three households without any registered cases showed that the only difference was the presence of toilets in the latter (1/5 versus 3/3; P = 0.01423). Among the 1,002 environmental specimens (including domestic and synanthropic animals and dust sampled in households) tested for T. whipplei DNA, only four specimens were slightly positive. Humans are currently the predominant identified reservoir and source of T. whipplei in these populations. Limited access to toilets and exposure to human feces facilitate the fecal-oral transmission of T. whipplei.