Mucoid bovine mastitis isolates of Streptococcus uberis - difficulties in identification

Highly mucoid Streptococcus uberis were isolated on blood agar from five milk samples originating from two dairy cow farms. All the isolates were CAMP test and esculin hydrolysis negative. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) following prior extraction with 70% formic acid was used for identification to the species level. Given that it is plausible that such strains could be isolated in the future from dairy cows by laboratories in Serbia and the Balkans, we consider this case report to be a useful instruction for veterinary bacteriology laboratories.