Bovine mastitis caused by Prototheca zopfii: first isolation in Chile

Abstract

The genus Prototheca includes unicellular achlorophyllous microalgae widely distributed in the environment, some of which could be pathogenic for human and animals. However, there is no previous report regarding these pathogenic microalgae causing infections in man or animals in Chile. Two-hundred milk samples collected from 150 dairy cows with clinical mastitis were inoculated onto PIM modified medium. Prototheca spp was isolated on two consecutive occasions from one cow sampled two months apart. Direct microscopic examination of wet smears made from milk samples revealed typical Prototheca cells. Biochemical tests based on carbon source assimilation identified the organism as Prototheca zopfii. This finding represents the first isolation of this environmental alga from bovine mastitis in Chile. This could be of great importance for mastitis control programs in dairy herds as Prototheca is an uncommon mastitis pathogen that does not respond to conventional antibiotic treatment.