Survey of the prevalence of Salmonella species on laying hen farms in Kosovo

A survey on the prevalence of Salmonella (S) species was carried out on 39 layer farms in Kosovo between April and September 2012. In total 367 samples, comprising feces, dust, eggs, and internal organs from dead birds, were investigated using bacteriological culture methods. Additionally, data on the location of the farm, the total number of birds on the farm, age of birds, and laying performance were collected. Salmonella were isolated from 38 samples obtained from 19 (49%) farms. The most common serovar identified was Salmonella enteritidis, found on 18 farms. The most common S. enteritidis phage type was PT29 followed by PT6, PT7, PT21, PT13a, PT8, PT14b, and PT4. One S. enteritidis isolate was not typable. Six farms had more than one phage type. Furthermore, serovar S. Bovismorbificans also was found in samples from 3 farms. Flock size or production stage was not associated with the probability of isolating Salmonella. The only flock factor found to be significantly associated was percent hen/day production: It was 2.8 times more likely to isolate Salmonella from flocks with production above 80% hen/day production compared to flocks producing at a lower level. Analysis of antimicrobial resistance patterns of 30 isolates revealed that all isolates were sensitive to gentamicin, ampicillin, sulphamethoxazole trimethoprim, and oxytetracycline, and 29 (97%) were sensitive to ciprofloxacin. All isolates showed intermediate resistance or were resistant to minocycline and cloxacillin. Twenty-six isolates (86%) had intermediate resistance to amoxicillin and 27 isolates (90%) were fully resistant to streptomycin. The present survey revealed a high prevalence of Salmonella enteritidis in layer flocks in Kosovo, indicating that table eggs have to be suspected as an important source of human salmone-llosis.