Cryptococcus tetragattii as a major cause of cryptococcal meningitis among HIV-infected individuals in Harare, Zimbabwe

Abstract

Objectives: HIV-associated cryptococcal meningitis is commonly caused by Cryptococcus neoformans, whilst infections with Cryptococcus gattii sensu lato are historically rare. Despite available studies, little is known about the occurrence of C. gattii sensu lato infections among HIV-infected individuals in Zimbabwe.

Methods: In a prospective cohort, we investigated the prevalence of C. gattii sensu lato meningitis among HIV-infected patients (n = 74) in Harare, Zimbabwe.

Results: Of the 66/74 isolates confirmed by molecular characterization, 16.7% (11/66) were found to be C. gattii sensu lato and 83.3% (55/66) C. neoformans sensu stricto. From one patient two phenotypically different C. gattii sensu lato colonies were cultured. The majority (n = 9/12; 75%) of the C. gattii sensu lato isolates were Cryptococcus tetragattii (AFLP7/VGIV), which has been an infrequently reported pathogen. In-hospital mortality associated with C. gattii sensu lato was 36.4%.

Conclusions: Our data suggests that C. tetragattii (AFLP7/VGIV) is a more common cause of disease than C. gattii sensu stricto (genotype AFLP4/VGI) among patients with HIV-associated cryptococcal meningitis in Harare, Zimbabwe and possibly underreported in sub-Saharan Africa.

Keywords: AFLP genotyping; Cryptococcal meningitis; Cryptococcus gattii; Cryptococcus neoformans; Cryptococcus tetragattii; HIV infections; Multilocus sequence typing; Mycological biotyping.