Genome analysis of two virulent Streptococcus thermophilus phages isolated in Argentina

GUGLIELMOTTI, D.M.; DEVEAU, H.; BINETTI, A.; REINHEIMER, J.; MOINEAU, S.; QUIBERONI, A.

INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY

Elsevier Science - International Union of Microbiological Societies and International Committee on Food Microbiology and Hygiene

Lugar: New York; Año: 2009 vol. 136 p. 101 - 109

0168-1605

Two Streptococcus thermophilus phages (ALQ13.2 and fAbc2) were previously isolated from breakdowns of cheese manufacture in Argentina. Complete nucleotide sequence analysis indicated that both phages contained linear double-stranded DNA: 35,525 bp in length for the pac-type phage ALQ13.2 and 34,882 bp for the cos-type phage fAbc2. Forty-four and forty-eight open reading frames (ORF) were identified for ALQ13.2 and fAbc2, respectively. Comparative genomic analysis showed that these isolates shared many similarities with the eight previously studied cos- and pac- phages infecting different S. thermophilus strains. In particular, part of the fAbc2 genome was highly similar to a region of phage 7201, which was thought to be unique to this latter phage. Protein analysis of the pac- phage ALQ13.2 using SDS polyacrylamide gel electrophoresis (SDS-PAGE) identified three major proteins and seven minor proteins. Parallel structural proteome analysis of fAbc2 revealed seven protein bands, two of which were related to major structural proteins, as expected for a cos-type phage. Similarities to other S. thermophilus phages suggest that the streptococcal phage diversity is not extensive in worldwide dairy factories possibly because related high-performing bacterial strains are used in starter cultures.