Comparative genotypic analysis of Candida krusei and Candida parapsilosis isolates from human and animal clinical samples through MLVA and RAPD-PCR profiling.

INTRODUCTION: Candida (C.) parapsilosis and C. krusei are significant fungal pathogens in both human and animal clinical settings. Molecular typing techniques, such as Multiple-Locus Variable Number Tandem Repeat Analysis (MLVA) and Random Amplified Polymorphic DNA Polymerase Chain Reaction (RAPD-PCR), play a crucial role in understanding the genetic diversity and epidemiology of these pathogens. The aim of the present study is to genotype the strains of C. krusei and C. parapsilosis isolated from human and animal clinical samples using MLVA and RAPD-PCR methods.

METHODS: A total of 30 human clinical samples, including 15 C. krusei and 15 C. parapsilosis candidates, were obtained from Imam Khomeini Hospital, and 30 animal samples, including 15 Candida krusei and 15 C. parapsilosis, were collected from veterinarians in dairy farms around Tehran. The study aimed to genotype strains of C. krusei and C. parapsilosis using MLVA and RAPD-PCR methods. Phenotypic confirmation of the Candida species was conducted, and genes related to virulence and antifungal resistance were examined using Multiplex-PCR. The genetic diversity of the strains was assessed using MLVA and RAPD-PCR methods, and dendrograms were constructed for each species.

RESULTS: The samples received from dairy farms or collected from the hospital were confirmed using phenotypic methods. The frequency of genes CDR1, CDR2, and MDR1 in C. krusei human samples were 66/86%, 33/13%, and 0%, respectively; in candidate C. krusei animal samples, they were 66/86%, 66/46%, and 20%; in C. parapsilosis human samples 80%, 40%, and 40%; in C. parapsilosis animal samples 66/86%, 66/66%, and 40%. Genetic relatedness analysis of 30 C. krusei samples was performed using microsatellite typing with the PHYLOViZ, which showed four clusters and four keys in the phylogenetic tree using the UPGMA method. Similarly, the genetic relatedness of 30 candidate C. parapsilosis samples was analyzed, which showed six clusters and six keys in the phylogenetic tree using the UPGMA method. Based on the RAPD-PCR results, all C. krusei samples were divided into six groups at a similarity level of 59%, with a simplicity index of 31/0. Similarly, all C. parapsilosis samples were divided into four groups at a similarity level of 59%, with a simplicity index of 35/0.

CONCLUSION: The RAPD-PCR method has shown limited discriminatory power compared to MLVA for genetic diversity assessment. However, the combination of MLVA and RAPD-PCR techniques provides a comprehensive approach to molecular typing and genetic characterization of C. parapsilosis and C. krusei isolates. This integrated approach offers valuable insights into the genetic diversity, epidemiology, and potential transmission dynamics of these strains, facilitating the development of targeted diagnostic and therapeutic strategies.