Clade Distinction and Tracking of Clonal Spread by Fourier-Transform Infrared Spectroscopy in Multicenter Candida (Candidozyma) auris Outbreak.

BACKGROUND

Candida (Candidozyma) auris has distinct genetic clades. Clade distinction is relevant for infection control and epidemiological purposes. State-of-the-art typing methodologies for clade distinction are based on genomic approaches, such as short tandem repeat (STR) analysis and whole-genome sequencing (WGS). However, they are time-consuming and expensive. Fourier transform infrared spectroscopy (FT-IR) is an alternative tool for strain typing based on their unique biochemical spectral profiles.

OBJECTIVES

To apply FT-IR to differentiate C. auris clades and evaluate epidemiological relationships based on biochemical data among isolates from a multicenter C. auris outbreak in the state of Pernambuco, northeastern Brazil.

METHODS

Sixty-nine C. auris strains from clades I, II, III, and IV were analysed. Fifty-nine were clade IV strains obtained from three outbreaks that took place in Pernambuco state, northeastern Brazil. An adjusted FT-IR spectroscopy protocol was applied to obtain carbohydrates and lipid fingerprints. Short Tandem Repeat (STR) analysis was used in order to validate the spectroscopy approach.

RESULTS

The adjusted preparation protocol for FT-IR analysis improved the spectral quality by 31.42% compared to standard protocol. FT-IR allowed us to discriminate C. auris clades I to IV. Moreover, important similarities were observed in C. auris clade IV strains obtained from two of the three hospitals, based on polysaccharides (1300-800 cm-1) plus lipids (3000-2800 cm-1 and 1500-1400 cm-1) spectra. STR confirmed the similarity results obtained by FT-IR, clustering the strains from two different hospitals.

CONCLUSIONS

The IR Biotyper is fast, easy-to-use, and a promising alternative for moderate-to-high-complexity laboratories to differentiate C. auris clades. Furthermore, this technique has the potential for isolate-level source tracking, which could be valuable for monitoring transmission routes in clinical settings.