Multilocus sequence typing of sequential Candida albicans isolates from patients with persistent or recurrent...

Area of Science:

• Medical Mycology
• Infectious Diseases
• Molecular Epidemiology

Background:

• Invasive candidiasis, particularly candidemia, poses a significant threat in healthcare settings.
• Understanding the genetic diversity and strain dynamics of Candida albicans is crucial for effective treatment and control.
• Multilocus sequence typing (MLST) and ABC typing are valuable molecular tools for analyzing fungal isolates.

Purpose of the Study:

• To investigate whether persistent or recurrent fungemia in patients is caused by the same or different strains of Candida albicans.
• To apply MLST and ABC typing to sequential isolates from patients with persistent or recurrent candidemia.
• To correlate strain types with antifungal susceptibility profiles.

Main Methods:

• Collected sequential Candida albicans isolates from 8 patients with persistent or recurrent candidemia across four Brazilian hospitals.
• Employed Multilocus Sequence Typing (MLST) and ABC typing to characterize the genetic relatedness of isolates.
• Assessed antifungal susceptibility profiles of the recovered strains.

Main Results:

• Except for one patient, sequential isolates from the same patient consistently showed identical MLST diploid sequence types (DSTs), ABC types, and antifungal susceptibility profiles.
• In one patient, seven sequential isolates collected over 10 days revealed three distinct Candida albicans strains.
• The seventh isolate from this patient was a rare Clade 2 strain, not previously observed in the larger cohort.

Conclusions:

• Most persistent or recurrent candidemia cases are attributed to a single Candida albicans strain.
• The simultaneous presence of three distinct C. albicans strains in a single patient with persistent bloodstream infection is a rare and significant finding.
• This study highlights the potential for complex strain dynamics even within a single infectious episode.