Abstract
The aim of the study was to evaluate the susceptibility of algae of the genus Prototheca to antifungal and antibacterial antibiotics. The study involved 27 isolates of Prototheca zopfii obtained from milk of mastitis-affected cows kept in a detached cowshed in the North-Eastern part of Poland. Analysis of P. zopfii susceptibility has demonstrated low effectiveness of both antifungal and antibacterial antibiotics. All algae isolated from milk were resistant to clotrimazole, fluconazole, econazole, flucytosine, cefoperazone, cephalexin, enrofloxacin, lincomycin, and oxytetracycline (100% of resistant isolates), as well as miconazole (92.6% of resistant isolates). Nystatin, ketoconazole, and amphotericin B showed the highest activity amongst the antifungal antibiotics (88.9% and 0.0%, 51.9% and 22.2%, 0.0% and 48.1% of susceptible and intermediate susceptible isolates, respectively). In the group of antibacterial antibiotics, the high activity against P. zopfii was observed only in the case of gentamicin, kanamycin (96.3% and 92.6% of susceptible isolates, respectively), and polymyxin B (59.3% of susceptible and 33.3% of intermediate susceptible isolates).