Genetic relatedness of Candida albicans bloodstream infection clinical isolates in Malaysia

ABSTRACT

Aims: The aim of this study was to investigate the genetic relatedness of the most prevalent Candida bloodstream infection (BSI) species in in a Malaysian population via Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) fingerprinting. Methodology and results: The genomic DNA of 43 Candida BSI blood culture samples obtained from Universiti Malaya Medical Centre (UMMC) was isolated, after which species identification was carried out using PCR with ITS-1 and ITS-4 pan-fungal primers in conjunction with CHROMagar™ Candida. The predominant Candida species in the BSI samples is Candida albicans (14 out of 43 isolates). RAPD-PCR on these 14 C. albicans clinical isolates was performed using PST as the arbitrary primer. Data analysis using MEGA found an overall non-relatedness of these 14 clinical isolates [average similarity coefficient (SAB) value 0.733±0.172]. Following in-depth analysis, five of the 14 isolates were observed to be identical (SAB values of 1.00 each), four isolates had SAB values of 0.80-0.99, indicating that they are highly similar, but are non-identical, while five isolates are unrelated (SAB lower than 0.80). This suggests that microevolution might have occurred and that these clinical isolates may possibly belong to different strains. Conclusion, significance and impact of study: A fair degree of genetic heterogeneity was found among the 14 C. albicans isolates from UMMC. To our knowledge, this is the first report on the genetic profiles of C. albicans bloodstream infection isolates from Malaysia, warranting further studies in the possible evolutionary trends within this Candida species in Malaysia. Keywords: Randomly Amplified Polymorphic DNA PCR (RAPD-PCR), Candida albicans, Candida bloodstream infections, Genetic relatedness, DNA fingerprinting