Valutazione dell’antibiogramma mediante un sistema inpiastra di isolati di Lactococcus garvieae da trote iridea(Oncorhynchus mykiss) allevate nel Nord Italia

SUMMARY – Lactococcosis due to Lactococcus garvieae is presently the most important bacterial disease in rainbow trout (Oncorhynchus mykiss) reared in Italy. Although good results have been obtained with vaccination, it is often necessary to use pharmaceuticals. Howere unsatisfactory results are often obtained as a result of the increasing resistance of this pathogen to antibiotic therapy. The aim of this work was to antibiogram evaluation by a plate system of some veterinarian chemotherapeutics (Enrofloxacin, Gentamicin, Ceftiofur, Neomycin, Erythromycin, Oxytetracycline, Tetracycline, Amoxicillin, Spectinomycin, Sulphadimetoxin, Sulphamethoxazole + Trimethoprim, Sarafloxacin, Sulphathiazole, Penicillin, Streptomycin, Novobiocin, Tylosine, Clindamycin) against 50 L. garvieae isolates obtained from North Italian trout farms from 1993 to 2004. All isolates were resistant to Sulphonamides, Tylosine and Sarafloxacin, while good results were obtained with Erythromycin and beta lactams (Amoxicillin and Penicillin). Our results offer some indications about the best chemotherapeutics most likely to be efficient feed when a disease outbreak is occurs.