Argentinean Lactococcus lactis bacteriophages: genetic characterization and adsorption studies.

AIMS

Characterization of four virulent Lactococcus lactis phages (CHD, QF9, QF12 and QP4) isolated from whey samples obtained from Argentinean cheese plants.

METHODS AND RESULTS

Phages were characterized by means of electron microscopy, host range and DNA studies. The influence of Ca(2+), physiological cell state, pH and temperature on cell adsorption was also investigated. The double-stranded DNA genomes of these lactococcal phages showed distinctive restriction patterns. Using a multiplex PCR, phage QP4 was classified as a member of the P335 polythetic species while the three others belong to the 936 group. Ca(2+) was not needed for phage adsorption but indispensable to complete cell lysis by phage QF9. The lactococci phages adsorbed normally between pH 5 and pH 8, and from 0 degrees C to 40 degrees C, with the exception of phage QF12 which had an adsorption rate significantly lower at pH 8 and 0 degrees C.

CONCLUSIONS

Lactococcal phages from Argentina belong to the same predominant groups of phages found in other countries and they have the same general characteristics.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work is the first study to characterize Argentinean L. lactis bacteriophages.