[Microsporidia in pediatric patients with leukemia or limphoma].

INTRODUCTION: Microsporidia are intracellular micro-organisms, characterized by mature spores with chitin walls and by one extrusive polar tube through which they pour their sporoplasm to the host cells. In immunocompromised patients, Enterocytozoon bieneusi and Encephalitozoon intestinalis produce diarrhea and systemic dissemination. In Mexico there is not information about microsporidia in children with cancer.

OBJECTIVE: The aim of this pilot study was to investigate the presence of microsporidia species in pediatric patients with leukemia or lymphoma.

MATERIAL AND METHODS: We obtained fecal samples from thirteen patients. The samples were processed to detect microsporidia by both modified Ziehl-Neelsen and clacofluor white stains, DNA was isolated to amplify rRNA specific sequences, to identify E. bieneusi, E. intestinalis, E. cuniculi and E. hellem by DNA polymerase chain reaction (PCR). Other parasites and pathogenic bacteria were also tested.

RESULTS: Based on morphologic traits 7/13 samples were found positives to microsporidia and 6/10 by PCR. Was identified E. bieneusi in three patients with leukemia and one with lymphoma, another two children with leukemia were infected with E. intestinalis. Almost all children were high-risk patients and in phase of re-induction, consolidation or with many chemotherapy treatments. All the patients with microspiridia did not present diarrhea at the moment of the sampling; however, in two children with diarrhea it was found Cyclospora cayetanensis. Also we obtained feces from five patients' mothers and microsporidia spores were identified by stain in all of them and by PCR it was diagnosed the species in three of them.

CONCLUSION: It was demonstrated that the feces of patients with leukemia or lymphoma had microsporidia, therefore is necessary to know the prevalence of these microorganisms and to analyze their impact in evolution of cancer patients.