A one health perspective on Diutina catenulata: Phenotypic traits, stress sensitivity, and virulence across diverse isolates

Diutina catenulata, formerly Candida catenulata, is found in diverse substrates, including soil, food, animals, and humans. It is recognized as an emerging human pathogen responsible for various diseases, including invasive infections in susceptible hosts, particularly in immunocompromised individuals. This study aimed to assess the phenotypic profiles, in vitro responses to various stressful conditions, and in vivo virulence of D. catenulata isolates from different origins (human, veterinary, and environmental). In vitro antifungal susceptibility to fluconazole, voriconazole, micafungin and amphotericin B was also determined for all isolates. Most D. catenulata isolates exhibited a light blue coloration on CHROMID® Candida agar. Different profiles were observed on the Spider medium, suggesting different behavior among the isolates. All isolates of D. catenulata were highly sensitive to oxidative and osmotic stress as demonstrated by exposure to H₂O₂ and 1.5 M NaCl, respectively whereas no unique pattern was evidenced concerning the response to cell wall stressors or membrane stressors. In addition to acquired azole resistance for some isolates, these findings provide valuable insights into the strain-dependent responses of D. catenulata to various stress factors. Using Galleria mellonella, we highlighted a wide range of virulence profiles among the isolates. Overall, this research demonstrates that the observed responses are strain-dependent rather than sample-source-dependent.