[Contribution of PCR for detection and identification of intestinal microsporidia in HIV-infected patients.]
Résumé
AIM: Intestinal microsporidiosis are among the most frequent opportunistic diseases in immunocompromised subjects. This study aimed to evaluate the contribution of PCR for a better detection and species identification of microsporidia in stool specimens of HIV-infected patients. PATIENTS AND METHODS: Stool samples obtained from 119 HIV-infected Tunisian subjects were screened for intestinal microsporidiosis by light microscopy using Weber's modified Trichrome stain and by a PCR method using universal primers V1/PMP2 which amplified a common fragment of the small subunit rRNA gene of microsporidia. The obtained PCR products were then sequenced using an ABI PRISM 377 DNA sequencer. RESULTS: The results showed a better sensitivity of PCR in the detection of microsporidia with an infection rate of 14.3% significantly higher than that of 6.7% obtained by light microscopy (p=0.03). As previously described, intestinal microsporidiosis was associated with low CD4 cell counts; 23.9% infection rate in patients having CD4 cell count under 200/mm(3) against 5.6% in patients with higher CD4 cell count (p=0.008). The sequencing of 15 out of the 17 positive PCR products has confirmed in all cases the species identified based on the PCR fragment size i.e., 250pb for Enterocytozoon bieneusi (seven cases) and about 270pb for Encephalitozoon intestinalis (nine cases); one case revealed a double infection. CONCLUSION: PCR proved to be more effective than classical Trichrome stain for the diagnosis of intestinal microsporidiosis. Moreover, the ability of PCR to identify the species involved could also be useful for cases management.