Combating Infectious Disease with Probiotics 

25/06/07 Scientists at University College Cork have discovered that probiotic bacteria can protect against bacterial infection. The work was carried out in the Alimentary Pharmabiotic Centre (APC) in UCC, published recently in the prestigious scientific journal, the Proceedings of the National Academy of Sciences. In fact, an image based on the work of the group was also chosen to illustrate the cover of the journal, a significant achievement for the UCC-based team.

The APC, funded by Science Foundation Ireland, was set up investigate the beneficial roles of the bacteria found in the gastro-intestine of healthy humans. The research group examined a range of beneficial bacteria and found one specific probiotic bacterium (Lactobacillus salivarius UCC118) which was able to kill Listeria monocytogenes, an often lethal pathogen in pregnant women. The probiotic kills the pathogen by producing an antibiotic-like compound called a bacteriocin. Tests showed that Lactobacillus salivarius offered significant protection against Listeria infection but that a strain of non-bacteriocin producing Lactobacillus generated by the researchers did not. The results of the UCC work clearly demonstrate a role for bacteriocins in protecting the host against potentially lethal infections. The study is the first to clearly demonstrate a mechanism by which probiotic bacteria may act to help improve the health of consumers.

The results may prove to be very significant, in that Listeria monocytogenes is particularly dangerous during pregnancy, and in a number of other high risk groups, but is too rare to warrant vaccination or preventative antibiotic therapy. A probiotic taken during pregnancy could well provide protection against Listeria infection in a form which would be acceptable to expectant mothers.

The study was primarily conducted by Sinead Corr as part of her research towards her PhD, but also involved key contributions from other APC scientists Yin Li and Christian Riedel. The research was supervised by APC Principal Investigators Colin Hill, Cormac Gahan and Paul O’Toole from the Department of Microbiology and the School of Pharmacy, UCC.