Assessment of a Multiplex PCR for the Simultaneous Diagnosis of Intestinal Cryptosporidiosis and Microsporidiosis: Epidemiologic Report from a French Prospective Study.

Microsporidiosis and cryptosporidiosis are associated with chronic diarrhea in immunocompromised patients. The objectives of this study were to: i) assess a multiplex quantitative PCR assay targeting Cryptosporidium spp and the microsporidian Enterocytozoon bieneusi and Encephalitozoon spp, and ii) provide an update on the epidemiology of these pathogens. A prospective study was conducted from January 2017 to January 2019. Performance of the assay was assessed, and all cryptosporidia and microsporidia isolates were genotyped. The sensitivity of the multiplex PCR method reached 1 copy/μL for each targeted pathogen. The sensitivity of co-proantigen testing in the diagnosis of cryptosporidiosis was 73%. The sensitivity of microscopy in the diagnosis of cryptosporidiosis was 64%, and microsporidiosis, 50%. Among the 456 patients included, 14 were positive for Cryptosporidium spp (4 different species); 5, for E. bieneusi; and 2, for Encephalitozoon intestinalis. The overall prevalence of cryptosporidia was 3.1%, and of microsporidia, 1.5%; in kidney transplant recipients (n = 82), corresponding values were 7.3% and 2.4% (6 and 2 patients), respectively. Two cases of E. intestinalis infection were diagnosed in children who had traveled to the tropics. This study is the first to assess a multiplex quantitative PCR method for the simultaneous diagnosis of intestinal microsporidiosis and cryptosporidiosis. The highest prevalences of both pathogens were observed in kidney transplant recipients.