Synergistic effects of the Lactobacillus acidophilus S-layer and nisin on bacterial growth

MARIANO PRADO ACOSTA; SANDRA M RUZAL; MARIANA C ALLIEVI; MARÍA MERCEDES PALOMINO; CARMEN SÁNCHEZ RIVAS

APPLIED AND ENVIRONMENTAL MICROBIOLOGY

AMER SOC MICROBIOLOGY

Año: 2009 vol. 76 p. 974 - 977

0099-2240

ABSTRACT We have previously described a murein hydrolase activity for the S-layer of Lactobacillus acidophilus ATCC 4356. Here we show that, in combination with nisin, this S-layer acts synergistically to inhibit the growth of pathogenic Gram negative Salmonella enterica and potential pathogenic Gram positive bacteria, Staphylococcus aureus and Bacillus cereus. In addition, bacteriolytic effects were observed for the Gram positive species tested. We postulate that the S-layer enhances the access of nisin into the cell membrane by enabling it to cross the cell wall; while nisin provides the sudden ion-nonspecific dissipation of the proton motive force required to enhance the S-layer murein hydrolase activity.