METHODS AND KITS TO DETERMINE THE SENSITIVITY OF STRAINS OF LACTOCOCCUS LACTIS BACTERIA TO PHAGE INFECTION

摘要

A kit useful for determining the phage susceptibility of one or more strains of Lactococcus lactis by means of multiplex polymerase chain reaction (PCR) is described. The kit comprises: (a) a first primer pair adapted to generate a first amplicon correlating to a region of the cwps operon that is unique to L. lactis strains MG1363 and SK11; (b) a second primer pair adapted to generate a second amplicon correlating to a region of the cwps operon that is unique to L. lactis strains IL1403 and KF147; (c) a third primer pair adapted to generate a third amplicon correlating to a region of the cwps operon that is uniqueto L. lactis strains UC509.9 and CV56; and (d) optionally, a control primer pair adapted to amplify a sequence conserved in L.lactis. The methods and kits of the invention may be employed to type strains of L. lactis into phage-sensitivity groups, and sub-type the phage-sensitivity groups according to phage sensitivity. The invention also described methods for formulation of mixed defined starter cultures using strains from different phage sensitivity groups.