Detection of Microsporidia, cryptosporidia and Giardia in swimming pools: a one-year prospective study.

In order to estimate the rate of microsporidia, cryptosporidia and giardia contamination of swimming pools, sequential samples of water were collected during a one-year period in six different swimming pools in Paris, France. Fourty-eight samples were submitted to filtrations. Eluates were examined for microsporidia using polymerase chain reaction (PCR) and for cryptosporidia and giardia using immunofluorescence staining. One of 48 specimens was positive for microsporidia. Using DNA sequence analysis, unknown microsporidia species were identified, which were close to an insect microsporidia Endoreticulatus schubergi. One sample was positive for cryptosporidia and none were positive for giardia. This study shows a low level of swimming pool water contamination by microsporidia, cryptosporidia or giardia, demonstrating the efficacy of cleaning filtration and disinfection procedures used in French swimming pools.

Search for Enterocytozoon bieneusi infection in wild monkeys in Cameroon.

Faecal samples collected from 42 wild monkeys in Cameroon were examined for microsporidia by light microscopy (using Weber trichrome and Uvitex 2B stains) and by PCR (using Enterocytozoon bieneusi specific primers). None of the 42 samples was positive, suggesting that wild monkeys do not represent a major reservoir for microsporidia in Central Africa.

Evidence of different Enterocytozoon bieneusi genotypes in patients with and without human immunodeficiency virus infection.

We classified 100 Enterocytozoon bieneusi isolates into five genotypes by a PCR-restriction fragment length polymorphism method. Type I strains were encountered only in human immunodeficiency virus (HIV)-infected patients, whereas type II strains were more frequently found in non-HIV-infected patients (75 versus 10%, respectively; P < 10(-4)), suggesting differences in the epidemiology of E. bieneusi among these patients.

[Microsporidiosis]. / Les microsporidies.

OPPORTUNISTIC PARASITES: Microsporidia are primitive eukaryotic parasites widespread in a large range of animal species. These opportunistic parasites can cause infections in humans, mainly in immunocompromised patients. PATHOGENIC SPECIES: Four microsporidian species are important in human pathology, Enterocytozoon bieneusi, Encephalitozoon intestinalis, Encephalitozoon cuniculi and Encephalitozoon hellem. LABORATORY DIAGNOSIS: A difficult task, laboratory diagnosis is based on direct microscope visualization of the parasite. Special stains not used in routine practice are required for identifying spores. TREATMENT: Species differentiation, achieved with the polymerase chain reaction technique, is necessary to select the appropriate treatment. Treatment of the most common microsporidiosis (caused by Enterocytozoon bieneusi) with fumagillin is currently under assessment in an ANRS clinical trial.

Detection of microsporidia in surface water: a one-year follow-up study.

In order to estimate the rate and seasonal variation of Enterocytozoon bieneusi contamination of surface water, sequential samples of water from the River Seine in France were collected during a 1-year period. Each sample (300-600 l) was submitted to sequential filtrations, and the filters were then examined for microsporidia using light microscopy and nested polymerase chain reaction (PCR) for E. bieneusi. Amplified products were hybridized with a E. bieneusi-specific probe. Twenty-five samples of water were analyzed during 1 year. Microscopic examination of stained filters proved unreliable for the identification of spores. Using nested PCR, 16 of 25 specimens were positive (64%). Unexpectedly, E. bieneusi was identified in only one sample by specific hybridization underlining the lack of specificity of ours primers. Nevertheless, using DNA sequence analysis, unknown microsporidia species were identified in eight cases, which had highest scores of homology with Vittaforma corneae or Pleistophora sp. This study shows a low rate of water contamination by E. bieneusi suggesting that the risk of waterborne transmission to humans is limited.

Genetic homology among thirteen Encephalitozoon intestinalis isolates obtained from human immunodeficiency virus-infected patients with intestinal microsporidiosis.

The ribosomal DNA internal transcribed spacer sequences of 13 unrelated Encephalitozoon intestinalis isolates obtained from human immunodeficiency virus (HIV)-infected patients with intestinal microsporidiosis were analyzed by gene amplification and DNA sequencing. Among these isolates, we found only one genetic lineage which suggests that E. intestinalis may have a clonal distribution in HIV-infected patients.

Disseminated infection due to Encephalitozoon cuniculi in a patient with AIDS: case report and review.

OBJECTIVE AND METHODS: Infections due to microsporidia are increasingly recognized as opportunistic infections in patients with AIDS. We describe here a case of disseminated infection due to Encephalitozoon cuniculi and review the literature on this microsporidial infection. RESULTS: All 12 patients reported in the literature had AIDS and nine presented with disseminated infection involving the kidneys, sinuses, lungs, brain and conjunctiva. Asymptomatic infection was seen in three patients. Microsporidia were detected by light microscopy examination of urine samples in all the cases. Species identification was performed by various genotypic methods or transmission electron microscopy. Eight of 12 patients who received albendazole therapy experienced clinical improvement with documented clearance of spores in five of these eight patients. Two patients relapsed. CONCLUSIONS: E. cuniculi infection should be considered in severely immunocompromised HIV-infected patients with multi-organ involvement and fever, especially when renal failure is present. Microsporidial spores are usually seen in urine samples and in the involved organ. Albendazole therapy seems to be effective.

Intestinal microsporidiosis occurring in two renal transplant recipients treated with mycophenolate mofetil.

BACKGROUND: Intestinal microsporidiosis is a major cause of chronic diarrhea and malabsorption in patients with human immunodeficiency virus. Its occurrence in transplant recipients has exceptionally been reported to date. METHODS: We report what we believe are the first two cases of intestinal microsporidiosis in renal transplant recipients. The patients were treated with mycophenolate mofetil. RESULTS: The clinical presentation was chronic diarrhea with massive weight loss. Stool analysis revealed microsporidian spores, identified as Enterocytozoon bieneusi spores by polymerase chain reaction. The onset of this opportunistic infection in these two patients is believed to be secondary to an increase in immunosuppression after azathioprine replacement by mycophenolate mofetil. The withdrawal of mycophenolate mofetil led to clinical recovery. CONCLUSION: The incidence of microsporidiosis will probably increase in transplant recipients treated with powerful immunosuppressants. Therefore, we recommend a systematic search for microsporidian spores in stool specimens in cases of unexplained diarrhea in these patients.

Risk factors for intestinal microsporidiosis in patients with human immunodeficiency virus infection: a case-control study.

A prospective unmatched case-control study was conducted to determine risk factors for intestinal microsporidiosis in persons infected with human immunodeficiency virus (HIV) who had < or = 200 CD4 cells/mm3. In multivariate analysis, case-patients (n = 30) were more likely than were control-subjects (n = 56) to have < or = 100 CD4 cells/mm3 (odds ratio [OR], 6.5; 95% confidence interval [CI], 1-42), to report male homosexual preference (OR, 7.6; 95% CI, 1-59.5), and to report swimming in a pool in the previous 12 months (OR, 9.2; 95% CI, 2.1-38.9). In summary, intestinal microsporidiosis in persons with HIV infection and < or = 200/mm3 CD4 cells is associated with male homosexuality and swimming in pools, suggesting fecal-oral transmission, including sexual and waterborne routes.

Determination of types of Enterocytozoon bieneusi strains isolated from patients with intestinal microsporidiosis.

To determine the types of Enterocytozoon bieneusi strains associated with intestinal microsporidiosis, we developed a rapid and efficient approach for typing parasites obtained from stool specimens by PCR-restriction fragment length polymorphism (PCR-RFLP). Typing was based on DNA polymorphism of the ribosomal DNA internal transcribed spacer (ITS) region of E. bieneusi. RFLPs generated with two restriction enzymes (NlaIII and Fnu4HI) in PCR-amplified ITS products were used to classify strains into different lineages. This approach was successfully used to differentiate 78 strains that had been obtained from the stools of 65 patients with intestinal microsporidiosis. Among the 78 strains, we found four genetically unrelated lineages, showing the genetic diversity of E. bieneusi. Type I strains of E. bieneusi were found in a majority of the samples, accounting for 51 (78%) of the 65 microsporidiosis cases. In contrast, type II, III, and IV strains were found in only 8 (12%), 3 (5%), and 3 (5%) cases, respectively. All strains of E. bieneusi we have tested so far fall into one of four different lineages, and this study shows that human intestinal microsporidiosis is most often associated with type I strains. PCR-RFLP analysis of the ITS region of E. bieneusi should be useful for epidemiological studies.

Diagnosis of infections caused by Enterocytozoon bieneusi and Encephalitozoon intestinalis using polymerase chain reaction in stool specimens.

OBJECTIVE: To study the usefulness of polymerase chain reaction (PCR) for the species identification of microsporidia in stool specimens obtained from HIV-infected patients with Enterocytozoon bieneusi or Encephalitozoon intestinalis infections. SETTING: Infectious disease clinic in a university hospital. PATIENTS: Thirty-seven stool specimens from 29 HIV-infected patients with microsporidiosis were tested. The diagnosis of microsporidian infection was made by light microscopy of stool specimens and species identification was made by transmission electron microscopy of duodenal biopsies. Sixty-one stool specimens from 45 HIV-infected patients without microsporidiosis served as controls. METHODS: PCR was performed using DNA extracted from stools with two primers sets, one specific for E. bieneusi and one specific for E. intestinalis. RESULTS: A 1265 base-pair fragment of the small subunit ribosomal RNA (rrs) gene could be amplified from all 31 stool specimens infected with E. bieneusi. In addition, a 930 base-pair fragment of the rrs gene could be amplified from all six stool specimens infected with E. intestinalis. The 61 control stools were negative with both primers. CONCLUSIONS: These results suggest that a PCR based assay using species-specific primers sets can be used successfully for microsporidian species differentiation from stool specimens, thus obviating the need for invasive biopsy procedures.

Detection and species identification of intestinal microsporidia by polymerase chain reaction in duodenal biopsies from human immunodeficiency virus-infected patients.

Polymerase chain reaction (PCR) was used for the detection of microsporidian DNA in duodenal biopsies obtained from 28 human immunodeficiency virus (HIV)-infected patients with intestinal microsporidiosis. Duodenal biopsies from 23 HIV-infected patients without microsporidiosis served as controls. A generic primer set for human microsporidia was used at first for the PCR. Amplified products were detected in 26 (93%) of 28 biopsies from patients with intestinal microsporidiosis. All control biopsies were negative. Microsporidia species were identified using Southern blot hybridization with specific probes for Enterocytozoon bieneusi and Encephalitozoon intestinalis. This technique confirmed the transmission electron microscopy-based species identification. Similar results were obtained using PCR with species-specific primer sets for E. bieneusi and E. intestinalis. PCR testing of intestinal biopsy specimens can be used successfully for rapid detection and species differentiation of intestinal microsporidia and thus could be a valuable alternative to transmission electron microscopy.