Digoxigenin-labeled probe for rapid identification of nisinogenic Lactococcus lactis strains

From the nisZ gene sequence, a non-radioactive digoxigenin-labeled DNA prob e, was tested for detection of nisin-producing strains using polymerase cha in reaction amplification. The digoxigenin-labeled DNA probe clearly discri minated between nisin-producing and non-producing strains with a high degre e of sensitivity and specificity. By agarose gel electrophoresis, 1.4 ng of nisin DNA was detected using the digoxigenin-labeled DNA probe compared wi th 11 ng using direct polymerase chain reaction amplification. A colony hyb ridization method using digoxigenin-labeled DNA to selectively detect nisin ogenic bacteria showed that the nis-probe was specific and did not react wi th any other non-bacteriocinogenic and non-nisinogenic strains. (C) 1999 Fe deration of European Microbiological Societies. Published by Elsevier Scien ce B.V. All rights reserved.