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Updated: Dec 12, 2025

Using the Overlay Assay to Qualitatively Measure Bacterial Production of and Sensitivity to Pneumococcal Bacteriocins
Published on: September 30, 2014
Extensive bacteriocin gene shuffling in the Streptococcus bovis/Streptococcus equinus complex reveals gallocin D with
Daragh Hill1,2,3, Paula M O'Connor2,3, Eric Altermann4,5
1School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
Abstract:
Streptococcus gallolyticus LL009 produces gallocin D, a narrow spectrum two component bacteriocin with potent activity against vancomycin-resistant enterococci. Gallocin D is distinct from gallocin A, a separate two component bacteriocin produced by S. gallolyticus. Although the gene clusters encoding gallocin A and gallocin D have a high degree of gene synteny, the structural genes are highly variable and appear to have undergone gene shuffling with other streptococcal species. Gallocin D was analysed in laboratory-based experiments. The mature peptides are 3,343 ± 1 Da and 3,019 ± 1 Da and could be readily synthesized and display activity against a vancomycin resistant Enterococcus strain EC300 with a MIC value of 1.56 µM. Importantly, these bacteriocins could contribute to the ability of S. gallolyticus to colonize the colon where they have been associated with colorectal cancer.
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