Cryptococcosis—a systematic review to inform the World Health Organization Fungal Priority Pathogens List

Abstract

Cryptococcosis causes a high burden of disease worldwide. This systematic review summarizes the literature on Cryptococcus neoformans and C. gattii infections to inform the World Health Organization’s first Fungal Priority Pathogen List. PubMed and Web of Science were used to identify studies reporting on annual incidence, mortality, morbidity, antifungal resistance, preventability, and distribution/emergence in the past 10 years. Mortality rates due to C. neoformans were 41%–61%. Complications included acute renal impairment, raised intracranial pressure needing shunts, and blindness. There was moderate evidence of reduced susceptibility (MIC range 16–32 mg/l) of C. neoformans to fluconazole, itraconazole, ketoconazole, voriconazole, and amphotericin B. Cryptococcus gattii infections comprised 11%–33% of all cases of invasive cryptococcosis globally. The mortality rates were 10%–23% for central nervous system (CNS) and pulmonary infections, and ∼43% for bloodstream infections. Complications described included neurological sequelae (17%–27% in C. gattii infections) and immune reconstitution inflammatory syndrome. MICs were generally low for amphotericin B (MICs: 0.25–0.5 mg/l), 5-flucytosine (MIC range: 0.5–2 mg/l), itraconazole, posaconazole, and voriconazole (MIC range: 0.06–0.5 mg/l). There is a need for increased surveillance of disease phenotype and outcome, long-term disability, and drug susceptibility to inform robust estimates of disease burden.