Pathogens causing diarrhoea among Bangladeshi children with malignancy: Results from two pilot studies

BACKGROUND: Diarrhoea is a frequent symptom in children with cancer, and occurs due to a composite effect of underlying disease and immunosuppression consequent to therapy, malnutrition, and non-infective aetiologies such as mucositis. In a large proportion of cases, the aetiology of diarrhoea remains unknown but is often attributed to multiple pathogens including parasites. AIM: To identify and describe the pathogens causing diarrhoea in Bangladeshi children with cancer. METHODS: Two cross-sectional pilot studies were conducted involving paediatric oncology patients with diarrhoea. Stool samples were collected from children who were hospitalised with or without being treated with chemotherapy during the study period, and had diarrhoea at any stage during their admission. In the first study, stool samples were tested by conventional microbiological methods and by polymerase chain reaction for parasites, and by immunoassays for Clostridium difficile. In the second study, conventional microbiology was conducted for bacteria and parasites including an enzyme-linked immunosorbent assay for Cryptosporidium antigen, and in a subset, immunoassays for Clostridium difficile. RESULTS: In the first study Giardia lamblia was detected in 68.5% of samples, Entamoeba histolytica in 13%, Cryptosporidium in 5.6%, non-toxigenic C. difficile in 22.4%, and other bacteria in 5.2%. In the second study, E. histolytica was detected in 10% of samples, Cryptosporidium in 4.3%, G. lamblia in 1.4%, C. difficile in 5.1%, and other bacteria in 5.7% of samples. CONCLUSION: These pilot data suggest that parasites are important aetiologies of diarrhoea in Bangladeshi children with malignancy. While molecular diagnostic tools detect an array of stool pathogens with greater sensitivity, conventional diagnostic methods are also useful.