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Whipple’s Disease Pathogen Found in International Diarrhea Patients

By LabMedica International staff writers
Posted on 11 Mar 2021
Tropheryma whipplei is the causative agent of Whipple’s disease. The organism has also been detected in the feces of healthy or asymptomatic persons and in the feces of patients with diarrhea. Symptoms tend to develop slowly over many years in most people with this disease.

Whipple’s disease is a rare bacterial infection that most often affects the joints and digestive system. Whipple’s disease interferes with normal digestion by impairing the breakdown of foods, and hampering the body's ability to absorb nutrients, such as fats and carbohydrates. Whipple’s disease can also infect other organs, including the brain, heart and eyes.

Image: Micrograph of Whipple’s disease. This duodenal biopsy shows the characteristic feature of Whipple’s disease; foamy macrophages are present in the lamina propria cells (Photo courtesy of Nephron).
Image: Micrograph of Whipple’s disease. This duodenal biopsy shows the characteristic feature of Whipple’s disease; foamy macrophages are present in the lamina propria cells (Photo courtesy of Nephron).

An international team of scientists led by DRK Krankenhaus (Neuwied, Germany) investigate the role of enteric T. whipplei, and examined fecal specimens of patients with diarrhea using conventional methods and PCR to detect enteric pathogens and T. whipplei. The aim was to collect epidemiologic evidence regarding a causative role of T. whipplei in diarrhea. They investigated a total of 590 fecal samples. In South Africa, 97 of 100 targeted samples were usable. In Singapore, 193 of 200 targeted specimens contained sufficient material; of these, 19 were originally submitted for bacterial culture, 77 for rotavirus antigen testing, and 97 for both. In Germany, they tested samples from 300 patients. In South Africa and Singapore, patients were mainly children, both outpatients and inpatients.

The scientists used the LightCycler 480 instruments (Roche Molecular Diagnostics, Pleasanton, CA, USA), with determination of crossing point (Cp) values in positive samples. Multiplex PCR testing for other pathogens was performed using LightMix Modular Gastroenteritis Panel kits (TIB Molbiol, Berlin, Germany), as reported for Escherichia coli.

The investigators reproved that overall, 56 patients had positive test results for T. whipplei in the feces: 17 (17.5%) in South Africa, 29 (15%) in Singapore, and 10 (3.3%) in Germany. In South Africa, T. whipplei was the most common fecal organism, followed by Shigella, rotavirus, and adenovirus. In Singapore, rotavirus was the most frequently detected organism, followed by norovirus, T. whipplei, and Salmonella. In Germany, Clostridioides difficile was the most frequently detected organism, followed by T. whipplei and Blastocystis hominis; viruses were not sought in Germany. The frequency of C. difficile likely reflects the high proportion of elderly inpatients.

Fecal specimens testing positive for T. whipplei averaged 0.91 other pathogens per specimen, in contrast to only 0.46 per specimen in those testing negative for T. whipplei. Similarly, of the fecal specimens testing positive for T. whipplei, 69.6% contained other pathogens, in contrast to only 34.5% of the specimens testing negative for T. whipplei. Specimens containing T. whipplei contained other pathogens about twice as frequently as specimens without T. whipplei. In Singapore, one specimen contained four pathogens: T. whipplei, Blastocystis, astrovirus, and Dientamoeba.

The authors concluded that using diagnostic specimens from microbiology laboratories on three continents, they were able to confirm that T. whipplei can be found frequently in the feces of patients with diarrhea. Across the three locations, the numbers of traditional enteropathogens were significantly increased in specimens also containing T. whipplei, and they found an association between the presence of T. whipplei and Campylobacter. The findings support the hypothesis that enteric T. whipplei may not be causative for diarrhea. but may possibly be a result of different sanitary and climatic conditions.


Related Links:
DRK Krankenhaus
Roche Molecular Diagnostics
TIB Molbiol



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