Tropheryma whipplei DNA in bronchoalveolar lavage samples: a case control study

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.

Is PAS Stain Necessary to Exclude Whipple Disease in Duodenal Biopsies?

Objective. Whipple disease, caused by Tropheryma whipplei, is a rare infectious condition primarily presenting with malabsorptive diarrhea. Small bowel biopsies typically reveal foamy macrophages containing periodic acid-Schiff-positive/diastase (PAS/D) resistant T. whipplei bacilli, and PAS(D) staining is occasionally requested by clinicians in duodenal biopsies, which are often histologically unremarkable. The yield of PAS(D) staining in such biopsies has never been reported to our knowledge. Methods. The anatomic pathology database was searched for all specimens of duodenal biopsies stained with PAS(D) from 1993 to 2021. Specimens were categorized by the following histomorphologic features: unremarkable, nonspecific changes, or expansion of the lamina propria by aggregates of foamy histiocytes. Follow-up information was collected, including microbiologic confirmatory testing. Results. There was a total of 193 specimens of duodenal biopsies stained with PAS(D). Biopsies lacking foamy histiocytes on H&E (n = 158) were never PAS-positive. Thirteen biopsies contained PAS-positive histiocytes; 9 out of the 13 PAS-positive specimens were subsequently confirmed to be T. whipplei. Of the 193 specimens, 124 specimens had a clinical request for PAS(D) staining. Only 3 of the 124 (2.4%) specimens showed foamy histiocytes containing PAS-positive granules, all of which were confirmed positive for T. whipplei. Conclusion. PAS(D) staining is unnecessary to exclude Whipple disease in duodenal biopsies without foamy macrophage aggregates, regardless of clinical suspicion. Clinical suspicion-driven biopsies often yield negative results for Whipple disease.

Universal digital high-resolution melting for the detection of pulmonary mold infections

Invasive mold infections (IMIs) are associated with high morbidity, particularly in immunocompromised patients, with mortality rates between 40% and 80%. Early initiation of appropriate antifungal therapy can substantially improve outcomes, yet early diagnosis remains difficult to establish and often requires multidisciplinary teams evaluating clinical and radiological findings plus supportive mycological findings. Universal digital high-resolution melting (U-dHRM) analysis may enable rapid and robust diagnoses of IMI. A universal fungal assay was developed for U-dHRM and used to generate a database of melt curve signatures for 19 clinically relevant fungal pathogens. A machine learning algorithm (ML) was trained to automatically classify these pathogen curves and detect novel melt curves. Performance was assessed on 73 clinical bronchoalveolar lavage samples from patients suspected of IMI. Novel curves were identified by micropipetting U-dHRM reactions and Sanger sequencing amplicons. U-dHRM achieved 97% overall fungal organism identification accuracy and a turnaround time of ~4 hrs. U-dHRM detected pathogenic molds (Aspergillus, Mucorales, Lomentospora, and Fusarium) in 73% of 30 samples classified as IMI, including mixed infections. Specificity was optimized by requiring the number of pathogenic mold curves detected in a sample to be >8 and a sample volume to be 1 mL, which resulted in 100% specificity in 21 at-risk patients without IMI. U-dHRM showed promise as a separate or combination diagnostic approach to standard mycological tests. U-dHRM's speed, ability to simultaneously identify and quantify clinically relevant mold pathogens in polymicrobial samples, and detect emerging opportunistic pathogens may aid treatment decisions, improving patient outcomes.

IMPORTANCE

Improvements in diagnostics for invasive mold infections are urgently needed. This work presents a new molecular detection approach that addresses technical and workflow challenges to provide fast pathogen detection, identification, and quantification that could inform treatment to improve patient outcomes.

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.

Whipple's disease of the respiratory system: A case report

Whipple's disease (WD) is a multiple-system chronic disease caused by Tropheryma whipplei (T. whipplei) infection. The present study describes 3 cases of WD with clinical manifestations of cough, chest pain, headache, dyspnea, sputum, joint pain, abdominal pain, diarrhea and weight loss. Chest computed tomography (CT) showed signs of plaques, nodules and pleural thickening; and bronchoscopic alveolar lavage fluid metagenomic-sequencing indicated that it was T. whipplei. One patient was treated with meropenem as the starting regimen and two patients were treated with ceftriaxone as the starting regimen. Furthermore, two patients were provided with a maintenance regimen of cotrimoxazole and one was given a maintenance regimen of minocycline, which was combined with meropenem and ceftriaxone in order to improve their cough, chest pain, headache and dyspnea symptoms. To the best of our knowledge, there are few reports on WD of the respiratory system caused by T. whipplei, and differential diagnosis is the key to clinical diagnosis. When WD of the respiratory system is difficult to diagnose, metagenomic second-generation sequencing (mNGS) may be a better choice, which can achieve early diagnosis and early treatment. However, its clinical value is still limited; therefore, more research needs to be conducted in the future.

Acute pneumonia due to Tropheryma whipplei diagnosed by metagenomic next-generation sequencing and pathology: A case report

Tropheryma whipplei (TW) is a rod-shaped, gram-positive bacterium that, when chronically infects humans, can lead to multi-system pathologies, including joint pain, abdominal pain with diarrhea and weight loss, myocarditis, pericarditis, and neurologic inflammation. Moreover, acute infections can lead to bronchopulmonary infections, bacteraemia, and acute diarrhea. However, fewer cases of acute pneumonia due to TW have been reported, and this diagnosis is not well founded. Herein, we report a case of acute pneumonia caused by a TW infection. The patient, a middle-aged man, underwent bronchoscopic alveolar lavage, and the metagenomic next-generation sequencing of the lavage fluid suggested TW infection. A lung puncture biopsy tissue specimen was also positive based on periodic acid-Schiff staining. After confirming the diagnosis, the patient was administered ceftriaxone for anti-infection treatment, improving clinical symptoms and lung imaging results. Therefore, in cases where conventional anti-infective treatment is ineffective for patients with acute pneumonia, we should consider the possibility of TW infection, conduct prompt pathogenetic examination, and provide timely treatment after diagnosis to improve overall patient prognosis.

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.

Universal Digital High Resolution Melt for the detection of pulmonary mold infections

Background

Invasive mold infections (IMIs) such as aspergillosis, mucormycosis, fusariosis, and lomentosporiosis are associated with high morbidity and mortality, particularly in immunocompromised patients, with mortality rates as high as 40% to 80%. Outcomes could be substantially improved with early initiation of appropriate antifungal therapy, yet early diagnosis remains difficult to establish and often requires multidisciplinary teams evaluating clinical and radiological findings plus supportive mycological findings. Universal digital high resolution melting analysis (U-dHRM) may enable rapid and robust diagnosis of IMI. This technology aims to accomplish timely pathogen detection at the single genome level by conducting broad-based amplification of microbial barcoding genes in a digital polymerase chain reaction (dPCR) format, followed by high-resolution melting of the DNA amplicons in each digital reaction to generate organism-specific melt curve signatures that are identified by machine learning.

Methods

A universal fungal assay was developed for U-dHRM and used to generate a database of melt curve signatures for 19 clinically relevant fungal pathogens. A machine learning algorithm (ML) was trained to automatically classify these 19 fungal melt curves and detect novel melt curves. Performance was assessed on 73 clinical bronchoalveolar lavage (BAL) samples from patients suspected of IMI. Novel curves were identified by micropipetting U-dHRM reactions and Sanger sequencing amplicons.

Results

U-dHRM achieved an average of 97% fungal organism identification accuracy and a turn-around-time of 4hrs. Pathogenic molds (Aspergillus, Mucorales, Lomentospora and Fusarium) were detected by U-dHRM in 73% of BALF samples suspected of IMI. Mixtures of pathogenic molds were detected in 19%. U-dHRM demonstrated good sensitivity for IMI, as defined by current diagnostic criteria, when clinical findings were also considered.

Conclusions

U-dHRM showed promising performance as a separate or combination diagnostic approach to standard mycological tests. The speed of U-dHRM and its ability to simultaneously identify and quantify clinically relevant mold pathogens in polymicrobial samples as well as detect emerging opportunistic pathogens may provide information that could aid in treatment decisions and improve patient outcomes.

Lung cancer patient with Tropheryma whipplei and Nocardia co-infection

A 34-year-old male presented with lung shadow and was asymptomatic during medical examination. The patient had a prior history of thyroid tumors. Imaging manifestation showed a nodule in the medial segment of the right middle lobe, with partial obstruction of the distal bronchus within the lesion. Ground-glass and inflammatory nodules were observed in the anterior segment of the right upper lobe, as well as chronic inflammatory changes in the lower lobe of the right lung. Lung histopathological examination suggested invasive adenocarcinoma. A morphological examination of the bronchoalveolar lavage fluid revealed the presence of Tropheryma whipplei (TW) and Nocardia. Although TW infection has been reported in cancer patients, co-infection with Nocardia is a unique occurrence in this case. Opportunistic pathogens are common in immunocompromised patients but in this case, the patient was a young adult with normal immunity and an early-stage tumor with TW and Nocardia co-infection. We demonstrated the presence of rare microorganisms through imaging findings, combined with different staining methods of bronchoalveolar lavage fluid and lung tissue sections and evaluation of morphological characteristics. The aim of the present study was to provide early diagnosis and treatment of patients by improving microbial morphological detection.

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.

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 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.

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 coinfection of Mycobacterium tuberculosis and Tropheryma whipplei: a case report

Background

We diagnosed a clinical case of pulmonary infection involving Mycobacterium tuberculosis and Tropheryma whipplei in a patient with acute respiratory distress syndrome. The diagnosis was assisted by metagenomic next-generation sequencing of bronchoalveolar lavage fluid.

Case presentation

A 44-year-old Han Chinese inmate was transferred to the emergency department because of dry cough, chest tightness, and shortness of breath. The patient’s body temperature rose to 39.3 °C following empirical cephalosporin treatment for 1 week. The blood CD4+/CD8+ ratio was 0.7, suggesting immunodeficiency. Routine microbiological tests were performed, and tuberculosis interferon gamma release assays were positive. Mycobacterium tuberculosis polymerase chain reaction was also positive. Chest computed tomography scan revealed miliary nodules and ground-glass opacifications, which were in accordance with tuberculosis. To fully examine the etiology, we performed routine laboratory tests and metagenomic sequencing, the results of which indicated the presence of Mycobacterium tuberculosis and Tropheryma whipplei. We administered anti-tuberculosis regimen in combination with trimethoprim/sulfamethoxazole. The patient recovered, with chest computed tomography scan showing absorption of lesions.

Conclusions

Compared with traditional diagnostic methods such as culture and serology, metagenomic next-generation sequencing has the advantage of detecting a wide array of microorganisms in a single test and therefore can be used for clinical diagnosis of rare pathogens and microbial coinfections. It is particularly useful for immunocompromised patients as they are more prone to infection by opportunistic microorganisms.

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.

Whipple disease: a 15-year retrospective study on 36 patients with positive polymerase chain reaction for Tropheryma whipplei

Our institution has performed microbiological diagnosis of Tropheryma whipplei since 2001, initially with a PCR targeting 16S rRNA before the development of a quantitative PCR in 2012. Here we report the clinical characteristics of a cohort of patients suffering from Whipple disease (WD) and evaluate the impact of these molecular techniques. Patients with a positive PCR for T. whipplei between 2001 and 2016 were retrospectively collected from microbiological databases. Two infectious diseases specialists reviewed their medical records and classified them as definite WD, probable WD or carriage of T. whipplei without disease. A total of 1153 samples were tested for T. whipplei; 76 samples taken from 36 patients were positive. Fifteen were considered as presenting a definite WD, seven as a probable WD and 14 as carriers. Median age was 56.4 years (extremes, 6.6-76.1). Median time from symptoms to diagnosis was 3 years (2.5 months to 13.3 years). About 60% were immunosuppressed. The most frequent clinical presentations were joint pain (16/22), weight loss (15/22) and/or digestive tract disorder (15/22); 41% had neurological manifestations, 32% pulmonary involvement and 32% lymphadenopathies. Bacterial load in faeces or saliva were 88 425 copies/mL (IQR 6175-292 725) in definite and probable WD and 311 copies/mL (IQR 253-2090) in carriers, respectively. We observed a 90% PPV above 32 200 copies/mL in faeces. WD is a chronic multisystemic disease with frequent pulmonary involvement. Underlying immunodeficiency is commonly observed leading to more complex clinical presentation. Positive T. whipplei PCR in both stool and saliva has a high positive predictive value. Moreover, patients with WD present higher bacterial load in faeces with a threshold of >32 200 copies/mL predicting ongoing infection.

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.

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.

Detection of respiratory pathogens in clinical samples using metagenomic shotgun sequencing

PURPOSE

In this pilot study, we used shotgun metagenome sequencing (SMS) strategy on bronchoalveolar lavage (BAL) samples from hospitalized patients with suspected ventilate-associated pneumonia (VAP) in order to explore its potential for improving detection of ventilator-associated-pneumonia (VAP) etiology.

METHODOLOGY

In total, 67BAL samples from patients with VAP were tested with SMS strategy for detection of respiratory pathogens. Results of SMS and routine respiratory culture were compared.

RESULTS

SMS detected all pathogens recovered by cultivation approaches. In addition, putative pathogens other than the organisms recovered by culture were detected by SMS in culture-positive samples. In 40 of 45 (89  %) culture-negative samples, a potential pathogen was detected by SMS.

CONCLUSION

This proof-of-concept study demonstrates that SMS is able to detect bacterial, fungal and viral organisms in BAL, including culture-negative cases.

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.

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.