Recently recognised microbial enteropathies and HIV infection

The Prevalence of Cyclospora cayetanensis and Cryptosporidium spp. in Turkish patients infected with HIV-1

Opportunistic infections such as cryptosporidiosis and cyclosporiasis are commonly encountered in patients with acquired immunodeficiency syndrome (AIDS). We investigated the existence of opportunistic protozoans that significantly affect the quality of life in HIV-1 infected patients using conventional and molecular methods. The study group comprised 115 HIV-1 positive patients. In the identification of Cyclospora cayetanensis and Cryptosporidium, the formol-ether precipitation method was used and smears were evaluated in optical microscope by staining modified Ziehl-Neelsen (ZN). The primers and probes used for PCR were Heat shock protein 70 for C. cayetanensis and the oocysts wall protein for Cryptosporidium spp.. Cyclospora and Cryptosporidium spp. oocysts were detected in one and two patients, respectively, by staining, whereas we detected C. cayetanensis in three patients out of 115 (2.6%) by PCR, and Cryptosporidium spp. in a further three patients (2.6%). C. cayetensis was detected in patients with CD4 counts of 64 cells/μm, 182 cells/μm and 287 cells/μm, respectively. Cryptosporidium spp. was detected in patients with CD4 counts of 176 cells/μm, 241 cells/μm and 669 cells/μm. As conclusion, PCR method is faster and more sensitive than microscopic methods and to screen intestinal pathogens routinely in patients infected with HIV should not be neglected in developing countries like Turkey.

Eradication of cryptosporidium from a defunctionalized colon limb by refeeding stoma effluent

Over the last 40 years, cryptosporidium has increasingly been recognized as a cause of acute self-limiting diarrhea in normal hosts. In the immunocompromised patient, cryptosporidium may cause severe illness with prolonged diarrhea and malabsorption. Pharmacologic therapy of cryptosporidium relies on adequate delivery of drug metabolites to the colon. Here we describe a patient who developed toxic megacolon during induction therapy for leukemia, requiring ileostomy formation to proceed with leukemia treatment. Although the megacolon resolved promptly, the resulting isolation of the colon from the fecal stream prevented luminal delivery of active metabolites of anti-protozoal drugs, resulting in persistent cryptosporidiosis. Refeeding of the ileostomy output into the colon effectively eradicated cryptosporidium from the colon and permitted closure of the ileostomy.

Natural and experimental infection of immunocompromised rhesus macaques (Macaca mulatta) with the microsporidian Enterocytozoon bieneusi genotype D

Microsporidia are obligate intracellular parasites that cause opportunistic infections in AIDS and other immunocompromised patients. Eight simian immunodeficiency virus (SIV)-infected rhesus macaque monkeys (Macaca mulatta) were inoculated orally with Enterocytozoon bieneusi spores isolated from intestinal lavage fluid of an AIDS patient (genotype D) to study the natural history of this infection. Four monkeys were already naturally infected with E. bieneusi (also genotype D), and were included to determine if a second inoculum affected the course of illness. Spore shedding was detected in feces of all eight monkeys within the first week of experimental infection. Five monkeys died within 3.5 months of experimental E. bieneusi inoculation. Three of these five monkeys began the study with CD4+CD29+ T cell levels well below 20% of total T lymphocytes. Deaths were due to a variety of AIDS-related manifestations. Microsporidia did not appear to directly contribute to mortality but may have contributed to morbidity. At necropsy, microsporidia were found in bile and tissue sections of the gallbladder but not in the gut, kidneys, or liver. The percent CD4+CD29+ levels of the last three monkeys remained near the level observed at the time of inoculation. These monkeys lived more than 2 years after the end of the study and continued to shed spores. This study corroborates previous reports that E. bieneusi can be reliably transmitted to SIV-infected rhesus monkeys but indicates that the use of SIV-infected monkeys for the study of microsporidiosis is complicated by the confounding effect of other opportunistic or AIDS-related infections.

Infections gastro-intestinales chez le patient immunocompromis

Le tractus gastro-intestinal est fréquemment le siège de manifestations infectieuses chez les patients immunocompromis.

Les symptômes les plus fréquemment rencontrés sont l'odynophagie, la dysphagie et les diarrhées.

Ces affections sont plus souvent observées chez les patients HIV.

Ces affections gastro-intestinales sont de différents types: soit liées au virus HIV lui-même (entérite liée au HIV, œsophagite ulcérée idiopathique), soit liées à des germes également responsables d'infections chez les patients immunocompétents (Salmonellose, shigellose, …), soit des infections opportunistes (CMV, Mucormycose,Cryptosporidium, Mycobactéries,Isospora belli, …).

La prévalence, la pathogenèse, les manifestations cliniques, les aspects macroscopique et microscopique sont discutés pour chaque entité.

Chemotherapy for patients with multiple parasitic infections

Multiple parasitic infections have become increasingly recognized as a result of improvements in laboratory diagnosis and a growing population of immunocompromised individuals. This review examines the principles of chemotherapy in groupings of multiple infections which are of particular clinical significance.

Diarrhoea: a significant worldwide problem

Diarrhoea is a problem, not only of the developing world, but also of the Western world. However, the economic implications of diarrhoeal diseases are particularly evident in the poorer countries. The most common worldwide cause of diarrhoea is intestinal infection and infants, pre-school children, the elderly, and those with congenital or acquired immunodeficiency run a high risk of contracting such infections. Diarrhoeal disease can be classified into three major clinical syndromes: acute watery diarrhoea, bloody diarrhoea, and persistent diarrhoea. A number of different micro-organisms can cause infectious diarrhoea, depending on the clinical setting. The development of oral rehydration solution has provided a simple approach to rehydration and maintenance of hydration in patients with acute watery diarrhoea, and has been implemented worldwide under the auspices of the World Health Organization. However, rehydration does not treat the diarrhoea itself, which will persist until the infection resolves. Since the drugs currently used for the treatment of diarrhoea, such as the opiate agents and antibiotics, have limitations, the search continues for a drug that acts predominantly on secretory pathways without affecting gastrointestinal motility. Novel therapeutic approaches include 5-HT(2) and 5-HT(3) receptor antagonists, calcium-calmodulin antagonists, and sigma-receptor agonists. Another approach has concentrated on the antisecretory role of the neurotransmitter, enkephalin, and has resulted in the development of the enkephalinase inhibitor, racecadotril. This drug has true antisecretory activity, and has demonstrated good efficacy and tolerability in clinical trials.

Fractionation of sporogonial stages of the microsporidian Encephalitozoon cuniculi by Percoll gradients

Microsporidia are obligate intracellular parasites that are increasingly recognized as a cause of opportunistic infections in immunocompromised individuals. Encephalitozoon cuniculi has been identified in humans with AIDS and infects a wide range of mammalian hosts. Little is known about the metabolic processes that regulate growth and replication of microsporidia. Examination of the individual stages of development will facilitate such studies and reveal possible targets for drug therapy. The purpose of this study was to fractionate and purify stages of the microsporidian life cycle. Encephalitozoon cuniculi were cultured in RK-13 cells. The tissue supernatants containing multiple parasite stages, empty microsporidial husks and host cell debris were collected, washed, and subjected to differential centrifugation in 80% stock isotonic Percoll. Transmission electron microscopy and SDS-polyacrylamide gel electrophoresis were used to compare the content and purity of each fraction. Mature spores formed a band at a density of approximately 1.138 g/ml. Sporoblasts were found at densities between 1.102 g/ml and 1.119 g/ml. A mixture of sporonts, sporoblasts, microsporidial husks, and cell debris remained at the top of the gradient and additional centrifugation in 30% and 50% Percoll resulted in separation of these stages. These results represent the first step toward fractionating stages of microsporidia infecting humans.