BACTERIOLOGICAL MONITORING OF SALMONELLA-ENTERITIDIS CARRIER BIRDS AFTER DECONTAMINATION USING ENROFLOXACIN, COMPETITIVE-EXCLUSION AND MOVEMENT OF BIRDS

Two hundred and forty, four-week-old laying birds naturally infected w ith Salmonella enteritidis PT33 (Pasteur Institute phage typing system ) were randomly divided twice (before and during the treatments) to ob tain four separately housed groups of 60 birds and to study the effica cy of three decontamination treatments: enrofloxacin either with or wi thout the movement of birds to a clean area, and enrofloxacin combined with movement of birds and a competitive exclusion treatment, The con trol group remained untreated. In each group contamination with S ente ritidis was checked bacteriologically, every week from two months befo re until two months after the treatments began, All the samples taken from all the birds before the treatments began were S enteritidis-posi tive. After the treatments it was not possible to isolate salmonella e ither from the environment or from the faeces of the three treated gro ups. All the birds were humanely sacrificed at 22 weeks of age and sam ples of liver, spleen, ovaries and caeca were analysed for the presenc e of salmonella. The results demonstrated that although antibiotic the rapy, the movement of birds into a clean house and competitive exclusi on, either combined or not, had some efficacy in reducing infection le vels, it was not possible to decontaminate all the birds completely.