Presence of Antibiotic Resistant Enterococci in Rinses of Milking Equipment after Sanitation Process

Enterococci are common milk contaminants, and microbial contamination of milk by this group of microorganisms can occur from a variety of sources. Significance of enterococci can be assessed by many separated points of view, otherwise a lot of research has focused on the potential role of food enterococci as reservoirs and/or vehicles of antibiotic resistance. The aim of this investigation was to evaluate the occurence of enterococci in rinses of milking equipment (n = 38) on two farms using automatic sanitation system. Our results showed, that alkaline disinfectant (on chlorine basis) was effective towards enterococci because apart from 2 samples, their presence in rinses has not been determined. Average number of enterococci survived the aplication of acid disinfectant reached the value 5.00.101 CFU.ml-1. Together, 60 strains were randomly isolated and identified from the grown colonies of genus Enterococcus, and E. faecalis was the predominat species (69.6 %). In rinses, also E. faecium, E. mundtii and undefined enterococci were found. Among antibiotic resistant isolates, 83.9 % of isolates were sensitive to erytromycin (15mcg/disk) and resistant to vancomycin (30 mcg/disk) were 20 % of isolates.