Cystoisospora belli infection in an AIDS patient in China: Need for cautious interpretation of mNGS.

Cystoisospora belli (C. belli) is an opportunistic coccidian parasite. This case is the first reported C. belli infection associated with AIDS in China. C. belli infection of this case was diagnosed with the presence of oocysts using direct wet mount and Ziehl-Neelsen acid-fast stain method, and confirmed by polymerase chain reaction (PCR) and Sanger sequencing, ruling out the result of metagenomic next-generation sequencing (mNGS). This case demonstrates that C. belli infection in AIDS could be a potential risk factor for persistent diarrhea, and should not be neglected in non-endemic area and emphaise the necessity of accurate mNGS databases.