Campylobacteriosis is at present the most frequent zoonosis in humans and the main source is poultry meat
contaminated by Campylobacter jejuni. An alternative and effective approach to antibiotic administration to
livestock to reduce bacterial contamination is the use of probiotics, which can help to improve the natural
defence of animals against pathogenic bacteria. In this study 55 lactic acid bacteria and bifidobacteria were
screened for desirable properties for their application as probiotics against Campylobacter in poultry. All
bacteria were examined for their antimicrobial activity against three C. jejuni strains. Strains exhibiting the
highest anti-Campylobacter activity were examined for their survival in the gastro intestinal tract (low pH
and presence of bile salts) and food/feed processing conditions (high temperature, high NaCl concentration
and starvation) and basic safety aspects such as antibiotic susceptibility and hemolytic activity were studied.
On the basis of these activities, two strains, namely Lactobacillus plantarum PCS 20 and Bifidobacterium
longum PCB 133, were chosen for an in vivo trial in poultry. They were separately administered to healthy
chickens in order to evaluate their capability of colonizing the GI tract of poultry and to estimate their effect
on C. jejuni population. The results evidenced that L. plantarum PCS 20 was not present in poultry feces at
detectable concentration, whereas B. longum PCB 133 significantly increased after two weeks of daily
administration and its amount was still high after a wash-out period of 6 days. In the same period, C. jejuni
concentration in poultry feces was significantly reduced in chickens administered with B. longum PCB 133.
Therefore, B. longum PCB 133, possessing interesting probiotic properties and a marked anti-Campylobacter
activity both in vitro and in vivo, is an excellent candidate for being