P461 Cryptococcosis screening and isolates characterization in asymptomatic people living with HIV in Kinshasa, DRC

Background: Cryptococcal meningitis (CM) is a life-threatening invasive mycosis affecting people living with HIV (PLHIV) and has a high prevalence and case fatality rate in sub-Saharan Africa. While most PLHIV presenting CM are symptomatic, the asymptomatic ones are diagnosed following routine screening tests indicated for all advanced PLHIV (CD4 <200/μl). We, therefore, hypothesized that asymptomatic CM patients would be infected with different Cryptococcus spp. strains than those in symptomatic CM patients (referring to the parallel study conducted in the same clinics). This study describes the prevalence of serum and meningeal cryptococcosis in asymptomatic PLHIV presenting a CD4 count of <200 cells/μl in the screening context. We then characterized and determined the antifungal susceptibility of Cryptococcus spp. strains isolated from these patients. Methods: We performed cross-sectional screening for serum cryptococcal antigen (CrAg) in ambulant PLHIV with <200 CD4/μL in three clinics in Kinshasa (DRC). Lumbar puncture was indicated in positive patients to exclude a meningeal location for therapeutic purposes. The resulting cerebrospinal fluid (CSF) was then analyzed for CrAg and Cryptococcus spp. was isolated and characterized by MALDI TOF MS, serotyping PCR, ITS sequencing, and multilocus sequence typing (MLST). In addition, the EUCAST E.Def.7.3.2 microdilution procedure was followed to determine the susceptibility of strains to antifungal agents. Results: A total of 47 PLHIV out of 262 included were tested positive for serum CrAg (19%, 95% CI: 14.2–24.3) from which 46.8% (22/47) had a high antigenic titer (≥1/160). The prevalence of asymptomatic CM was then estimated at 50% in CrAg serum-positive patients who consented to lumbar puncture (19/38). Although the female proportion included in the study was higher than that of men, serum CrAg was more positive in men (21.4%, 18/84 men included) than in women (18.0%, 29/161 women included). While the mean CD4 count of CrAg serum-positive patients were significantly lower than that of negative patients (P <.05), the median viral load between the two patient groups was approximately similar (P >.05). Only four CSF samples were positive in culture for Cryptococcus spp. and were all characterized as Cryptococcus neoformans/serotype A. At this stage, two isolates have been analyzed using the ISHAM MLST scheme and two different sequence type (ST) profiles were identified, namely: ST93 and ST63. While ST93 is the main Cryptococcus neoformans profile described in Congolese (DRC) PLHIV with CM, ST63 has not yet been identified in the DRC before. Of note, epidemiological and clinical specificities of ST63 have so far been poorly characterized in the literature. Susceptibility testing against the major antifungals and the MLST typing of the two remaining strains are still ongoing. Conclusions: The prevalence of cryptococcosis should not be neglected among asymptomatic PLHIV in the DRC, to meaning that screening and preventive treatment measures should be integrated into the national policy for HIV management and related diseases. For the rest of the analyses still in progress, conclusions can only be drawn once they have been fully finalized.