Screening for cryptococcal antigenemia and meningeal cryptococcosis, genetic characterization of Cryptococcus neoformans in asymptomatic patients with advanced HIV disease in Kinshasa, Democratic Republic of Congo

Abstract

Abstract We evaluated the prevalence of serum and meningeal cryptococcosis in asymptomatic outpatients with advanced HIV disease (CD4 < 200 cells/mm3) in a cross-sectional screening context in Kinshasa clinics (DRC). Lumbar puncture (LP) was performed in patients with positive serum cryptococcal antigen (CrAg) test, and Cryptococcus spp. isolated from cerebrospinal fluid (CSF) were identified by MALDI-TOF-MS, and characterized using serotyping-PCR, ITS-sequencing and multilocus sequence typing (MLST). The genetic profiles obtained were then compared with those of isolates previously described in symptomatic patients in the same clinics. Forty-seven patients with advanced HIV disease out of 262 included were positive for serum CrAg (18%, 95% CI: 14.2–24.3). The prevalence of asymptomatic cryptococcal meningitis (CM) was then measured at 50% among patients with positive serum CrAg test who consented to LP (19/38). Only four CSF samples were culture positive and all were characterized as Cryptococcus neoformans, molecular type VNI and belonging to two different sequence types (ST): ST93 (3/4) and ST63 (1/4). While ST93 is also the main genomic profile described in advanced HIV disease patients with symptomatic CM in Kinshasa clinics, ST63 has not yet been identified in DRC before. It is likely that future studies involving a large number of strains will be necessary before any definitive conclusions can be drawn on the involved strains in asymptomatic patients.

Keywords

• Cryptococcal antigen screening
• People living with HIV
• Cryptococcosis
• Molecular characterization
• Antifungal susceptibility testing
• DRC