Multilocus Sequence Typing of Clinical Isolates of Cryptococcus from India

Area of Science:

• Mycology
• Infectious Diseases
• Molecular Epidemiology

Background:

• Cryptococcosis, a serious infection, is caused by Cryptococcus neoformans and Cryptococcus gattii species complex.
• Understanding the genetic diversity of these fungal pathogens is crucial for public health.
• Molecular epidemiology aids in tracking pathogen evolution and spread.

Purpose of the Study:

• To determine the molecular epidemiology of 208 clinical Cryptococcus isolates from India.
• To characterize the genetic profiles of Cryptococcus neoformans and Cryptococcus gattii species complex in India.
• To compare the genetic diversity of Indian isolates with global data.

Main Methods:

• Multilocus sequence typing (MLST) was performed on 208 clinical isolates.
• The ISHAM MLST consensus scheme for C. neoformans/C. gattii species complex was utilized.
• Phylogenetic analysis was conducted to assess genetic diversity.

Main Results:

• Ten Sequence Types (STs) were identified: 7 for C. neoformans and 3 for C. gattii.
• C. neoformans isolates were predominantly VNI type, with STs 31 and 93 being most common.
• C. gattii isolates included ST58 and ST215 (VGI) and ST69 (VGIV).
• Indian isolates exhibited lower genetic diversity compared to global MLST database data.
• No significant associations were found between prevalent STs and HIV status, geographic origin, or Minimum Inhibitory Concentration (MIC).

Conclusions:

• The molecular epidemiology of Cryptococcus in India is characterized by limited genetic diversity, particularly for C. neoformans.
• The predominant C. neoformans genotype in India is VNI.
• Further research is needed to understand the implications of this genetic profile on cryptococcosis in the Indian subcontinent.