ABSTRACT
Eight hundred and forty-eight strains of Staphylococcus aureus and coliforms isolated from milk samples taken from cows with clinical or subclinical mastitis were tested for their sensitivity to a range of antibiotics, comparing strains isolated in 1984, 1985, 1986 and 1987. The only increase in the proportion of resistant strains occurred with coliforms resistant to ampicillin and neomycin.
Subject(s)
Anti-Bacterial Agents/pharmacology , Enterobacteriaceae Infections/veterinary , Mastitis, Bovine/microbiology , Staphylococcal Infections/veterinary , Animals , Cattle , Enterobacteriaceae/drug effects , Enterobacteriaceae/isolation & purification , Enterobacteriaceae Infections/microbiology , Female , Microbial Sensitivity Tests , Milk/microbiology , Staphylococcal Infections/microbiology , Staphylococcus aureus/drug effects , Staphylococcus aureus/isolation & purificationABSTRACT
Six hundred and seventeen isolates of Staphylococcus aureus from subclinical clinical mastitis cases in 63 dairy herds in Northern Ireland were typed using a set of 25 phages. Ninety-four per cent of the isolates were typable, with nine phages, predominantly from groups I and III, being responsible for almost all of the lysis. Although 68 phage patterns were found, six of them typed 47.2% of the isolates. One strain accounted for 14.7% of the isolates, but the largest number of strains (44) was restricted to individual farms. The epidemiological significance of these findings for on-farm mastitis control is discussed.
