Characterisation of three temperate phages released from the same Lactobacillus paracasei commercial strain

Lysogeny entails more economical and technological risks in probiotic Lactobacillus casei/paracasei bacteria than in other lactic acid bacteria, due to economic value. Lysogeny is widely spread among L. casei/paracasei strains. Siphophages C_L1 and C_L2, isolated from noninfected lysed‐cultures of commercial L. paracasei A, are thermoresistant, have identical host spectrum, latent and burst times, whereas burst sizes are 148 and 85, respectively. Mitomycin C induction of L. paracasei A yielded prophage iA2, whose presence was confirmed on the strain genome and whose restriction patterns differed from phages C_L1 and C_L2. The latter shared several restriction fragments, probably indicating a common origin.