Cryptosporidium gastroenteritis in Egyptian children with acute lymphoblastic leukemia: magnitude of the problem.

PURPOSE: Cryptosporidium species is considered to be an important cause of significant morbidity in immunocompromised individuals. A prospective case-control study of sporadic diarrhea due to Cryptosporidium infection was conducted on children with acute lymphoblastic leukemia (ALL). METHODS: Forty children with ALL on maintenance chemotherapy according to the Berlin-Frankfurt-Munster (BFM-90) protocol and 45 sex- and age-matched controls were studied. The ALL group included 25 patients with acute diarrhea and 15 without diarrhea, and the control group included 30 children with acute diarrhea and 15 without. Collected stool specimens were examined using modified Ziehl-Neelsen (MZN) and modified trichrome stains. Serum Cryptosporidium Parvum immunoglobulin G (IgG) antibodies were detected by enzyme-linked immunosorbent assay. RESULTS: Cryptosporidium oocysts, pathogenic Gram-negative organisms, Giardia lamblia, and Entamoeba histolytica were identified in the stool samples (fecal specimens) of six (24%), eight (32%), four (16%), and two (8%), respectively, of the 25 patients with ALL and actute diarrhea and in one (3%), two (6.5%), six (20%), and five (16.5%), respectively, of the 30 control patients with diarrhea. Serum IgG antibodies were positive in four of the six ALL patients and in one of the control group patients with Cryptosporidium diarrhea who tested positive for oocysts in the stool. Diarrhea duration and severity were greater in ALL patients with stool-positive Cryptosporidium oocysts than in those with non-Cryptosporidium-positive diarrhea (p < 0.000). CONCLUSIONS: Cryptosporidium infection should be considered in children with ALL presenting with prolonged or severe watery diarrhea during chemotherapy, especially those treated with methotrexate and 6-mercaptopurine. Since Cryptosporidium is not routinely tested for in stool examination, a MZN stain is recommended.

Diagnosis of Toxoplasma gondii infection after allogeneic stem cell transplant can be difficult and requires intensive scrutiny.

Infectious complications remain a major problem after allogeneic hematopoietic stem cell transplant (HSCT). Specifically Toxoplasma gondii infection is a life-threatening condition in immunocompromised patients. In order to highlight the difficulties in obtaining an early and definitive diagnosis, we report three cases of toxoplasmosis after HSCT for hematologic malignancies: two cases of T. gondii retinochoroiditis, and one case of encephalitis. All patients had unrelated donors and received antithymocyte globulin; none had received trimethoprim/sulfamethoxazole prophylaxis. Toxoplasmosis occurred early post-transplant and diagnosis was obtained by real-time PCR. In one case, the correct diagnosis could only be established by PCR analysis of a retinal biopsy specimen. Rapid diagnosis--by invasive approaches--and an immediate onset of antiparasite treatment are crucial to avoid disseminated and often lethal Toxoplasma infections in the post-transplant period. Post-transplant prevention strategies and treatment to control advanced infection in this setting are discussed.

A preliminary study of the prevalence of intestinal parasites in immunocompromised patients with and without gastrointestinal manifestations.

The objective of the present study was to determine the prevalence of the intestinal parasites most commonly found in immunocompromised patients. A group of 111 individuals with acute lymphoid leukaemia (ALL), chronic myeloid leukaemia (CML), human immunodeficiency virus (HIV) and other immunocompromised conditions (principally haematological disorders) was selected. A battery of tests was performed on each individual to identify the presence of parasites (three stool specimens with saline solution and Lugol both directly and by concentration, culture and special staining). No significant differences were found among the frequencies of the different parasites with the several types of immunocompromised conditions. The overall frequencies of potentially pathogenic and opportunistic parasites were 32.4% (36/111) and 9% (10/111) respectively, the most frequently encountered among the latter being Cryptosporidium sp., Microsporidia spp. and Strongyloides stercoralis.

Failure of systemic empirical treatment with amphotericin B to prevent candidemia in neutropenic patients with cancer.

We undertook a retrospective review of all patients with hematologic malignancies in whom candidemia developed during chemotherapy-induced neutropenia in 1989 and 1990. Candidemia developed in 11 patients; five were receiving therapeutic doses of amphotericin B at the time of infection. Disseminated infection occurred in 2 of 5 patients with breakthrough infection and 3 of 6 patients with candidemia before receipt of amphotericin B. Among patients with breakthrough candidemia there was a trend toward more-prolonged neutropenia prior to infection (P = .069), but otherwise they were indistinguishable from other candidemic patients with regard to risk factors for candidemia. Amphotericin B-susceptible Candida albicans was isolated from two patients and Candida krusei from three patients with breakthrough infection. All patients were treated with amphotericin B; all breakthrough infections responded to treatment. Neutropenic patients with breakthrough candidemia were clinically similar to those whose candidemia preceded amphotericin B therapy, and there was no increase in morbidity and mortality among individuals with breakthrough infection.