EQUINE SALMONELLOSIS IN A DUTCH VETERINARY TEACHING HOSPITAL

During 1990 and 1991, 380 faecal samples were collected from horses wi th diarrhoea. Sixty-nine (18 per cent) of the samples yielded a positi ve culture for Salmonella species, and salmonellae were cultured direc tly from 37 (54 per cent) of these cases. In 32 (46 per cent) of the c ases the salmonellae were found after culturing the organism in an enr ichment medium. Salmonella typhimurium was isolated from 43 samples, S hadar from three samples, S arizona from two, S enteritidis from two, S virchow from one, S blockley from one and S bareilly from one sampl e. In 1990, S typhimurium phage type 200 was the predominant phage typ e, whereas in 1991 phage types 510, 656 and 658 were encountered most often. The antibiotic susceptibility of 53 of the 69 isolates was asse ssed and 28 of them were resistant to more than three antimicrobial ag ents. Resistance to streptomycin and the tetracyclines was common, but most of the isolates were sensitive to gentamicin and nitrofurantoin.