Novel fluconazole-resistant zoonotic yeast isolated from mastitis

A hospital-based cross-sectional study was conducted during 2018-2019 to decipher the prevalence of yeast mastitis. The results indicated a 19.68% prevalence of clinical mastitis in bovines. Among them, 5.51% of samples revealed yeasts constituting 1.09% overall prevalence. Candida albicans was recorded as a significant fungal agent involved in clinical bovine mastitis. We record the association of Kodamaea ohmeri in clinical bovine mastitis. On proteomic and molecular confirmation, K. ohmeri isolates were re-identified from phenotypically identified Candida isolates associated with bovine mastitis. After conventional identification, the yeast isolates were re-identified by MALDI-TOF MS-based proteomic approaches. The D1/D2 domains of 26S-rRNA gene and 5.8S-internal transcribed spacer (ITS) rDNA regions based molecular phylogenetic analysis identified the isolates as K. ohmeri. The isolates were resistant to fluconazole. This study reports the first systemic study of K. ohmeri isolates recovered from bovine clinical mastitis, utilizing conventional, automated, proteomic, and genomic approaches followed by antifungal susceptibility. The findings suggest K. ohmeri as a potent opportunistic emerging pathogen of veterinary and public health concern, need for accurate identification of fungal agents from mycotic mastitis, and use of validated antifungal susceptibility assay because of developing resistance to antimycotic agents. Our findings suggest judicious use of fluconazole and alternative antifungal agents may be considered in case of an outbreak.