Comparison of lactococcal bacteriophage isolated in the United States and Argentina.

Bacteriophage of Lactococcus lactis ssp. lactis and ssp. cremoris, isolated in the United States and Argentina, were compared with respect to host range, adsorption, latent period, burst size and immunological cross-reactivity. Only 1 out of 13 U.S. culture isolates was sensitive to Argentinian phage. Argentinian L. lactis ssp. lactis C2 mutants were resistant to 13 U.S. phage isolates (4 prolate and 9 isometric). While Argentinian phage Stl-3 multiplied on U.S. culture isolate 59-1, low adsorption (38%) and insignificant burst size and latent period data were evident. Antisera prepared against U.S. phage D59-1 (prolate) and F4-1 (isometric) neutralized the lytic activities of all Argentinian prolate phage although the F4-1 antiserum was less effective. The data suggest homology especially between U.S. phage D59-1 and the Argentinian phage.