Isolation and phenotypic characterization of Lactobacillus casei/paracasei bacteriophage resistant mutants

CAPRA, M. L.; MERCANTI, D.; ROSSETTI, L.; REINHEIMER, J.; QUIBERONI, A.

JOURNAL OF APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: London; Año: 2011 vol. 111 p. 371 - 381

1364-5072

Aims: To isolate and characterize bacterial strains derived from Lactobacillus casei and Lactobacillus paracasei strains and resistant to phage MLC-A. Methods and Results: Two out of nine assayed strains rendered resistant mutants with recovery efficiencies of 83% (Lact. paracasei ATCC 27092) and 100% (Lact. casei ATCC 27139). DNA similarity coefficients (RAPD-PCR) confirmed that no significant genetic changes occurred while obtaining resistant mutants. Neither parent nor mutant strains spontaneously released phages. Phage resistant mutants were tested against phages PL-1, J-1, A2 and MLC-A8. Lact. casei ATCC 27092 mutants showed, overall, lower phage resistance than Lact. paracasei ATCC 27092 ones, but still higher than the parent strain. Lact. paracasei ATCC 27092 mutants moderately adsorbed phage MLC A, only in calcium presence, though their parent strain successfully did it with or without calcium. Adsorption rates for Lact. casei ATCC 27139 and its mutants were highly influenced by calcium. Again, phage adsorption was higher on the original strain. Conclusions: Several isolates derived from two Lact. casei and Lact. paracasei strains showed resistance to phage MLC-A but also to other Lact. casei and Lact. paracasei phages. Significance and Impact of Study: This study highlights isolation of spontaneous bacteriophage resistant mutants from Lact. casei and Lact. paracasei as a good choice for use in industrial rotation schemes.