Nanoparticles as New Antifungals in the Prevention of Bovine Mycotic Mastitis Caused by Candida spp. and Diutina spp.—In Vitro Studies

Bacterial infections are the primary cause of <i>mastitis</i> in dairy cattle. Fungal <i>mastitis</i> occurs in 1-12% of cases. Antibiotic therapy, the standard treatment for <i>mastitis</i>, has led to antibiotic-resistant bacteria, reducing treatment efficacy and increasing fungal <i>mastitis</i> occurrence. Antibiotics lack biocidal effects on fungi, which often exhibit resistance to antifungal agents. This study evaluated the antifungal properties of nanoparticles (NPs) against <i>Candida albicans</i>, <i>Candida glabrata</i>, <i>Candida parapsilosis</i>, <i>Diutina rugosa</i> var. <i>rugosa</i>, <i>Diutina catenulata</i>, and <i>Diutina rugosa</i>. Tested NPs included gold (AuNPs), silver (AgNPs), copper (CuNPs), iron with hydrophilic carbon coating (FeCNPs) (1.56-25 mg/L), and platinum (PtNPs) (0.625-10 mg/L), along with their complexes. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) at 0.75-25 mg/L for AuNPs, AgNPs, CuNPs, and FeCNPs and 0.313-10 mg/L for PtNPs, as well as fungal sensitivity to standard antifungals, were determined. Each strain showed different sensitivities depending on the NPs used and their concentrations. <i>C. glabrata</i> was the most resistant to nanoparticles, while <i>D. catenulata</i> was the most susceptible. PtNPs and FeCNPs showed no or weak biocidal properties. Some mycotic-resistant strains were sensitive to nanoparticles. This study indicates a high in vitro antifungal potential for the application of nanoparticles, especially AgCuNPs, as a new effective non-antibiotic agent for the prevention and control of mycotic <i>mastitis</i> in dairy cattle.