Specific Bifidobacterium strains isolated from elderly subjects inhibit growth of Staphylococcus aureus

• Published in: International journal of food microbiology Vol. 117; no. 1; pp. 125 - 128
• Main Authors: Lahtinen, Sampo J., Jalonen, Lotta, Ouwehand, Arthur C., Salminen, Seppo J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 10.06.2007; Elsevier
• Subjects: Aged, 80 and over; antibacterial properties; Antibiosis - physiology; Antimicrobial activity; bacterial contamination; Bifidobacteria; Bifidobacterium; Bifidobacterium - physiology; Bifidobacterium lactis; Biological and medical sciences; Bioluminescence; cell free system; Colony Count, Microbial; elderly; Escherichia coli; Escherichia coli K12; Escherichia coli K12 - growth & development; Food industries; Food microbiology; food pathogens; Fundamental and applied biological sciences. Psychology; Gastrointestinal Tract - microbiology; heat stability; Humans; hydrogen peroxide; Hydrogen Peroxide - metabolism; Inhibition; Intestinal microbiota of the elderly; intestinal microorganisms; lactic acid bacteria; Lactobacillus reuteri; Luminescence; organic acids and salts; probiotics; Salmonella enterica; Salmonella enterica subsp. enterica serovar Typhimurium; Salmonella Typhimurium; Salmonella typhimurium - growth & development; serotypes; Staphylococcus aureus; Staphylococcus aureus - growth & development; Staphylococcus aureus subsp. aureus; Antimicrobial activity; Bioluminescence; Inhibition; Bifidobacteria; Intestinal microbiota of the elderly; Staphylococcus aureus; Bifidobacterium; Actinomycetaceae; Growth; Microflora; Antimicrobial agent; Strain; Actinomycetales; Bacteria; Micrococcales; Actinomycetes; Micrococcaceae
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2007.02.023

Cell-free, pH-controlled supernatants of thirty-eight Bifidobacterium strains isolated from healthy elderly subjects were subjected to antimicrobial activity assay. Bioluminescent indicator strains Staphylococcus aureus RN4220, Escherichia coli K-12, and Salmonella enterica serovar Typhimurium ATCC 14028 were used as targets of antimicrobial activity. The effect of nutrient depletion on the inhibition was eliminated with spent-culture controls. Three out of thirty-eight Bifidobacterium strains were capable of inhibiting the growth of S. aureus. The inhibition was equal to 23.2 ± 19.1% to 50.4 ± 26.7% of the inhibition caused by 50 IU/ml nisin. Reuterin-producing positive strain Lactobacillus reuteri SD2112 was capable of 86.0 ± 24.6% inhibition, but Bifidobacterium lactis Bb-12, a known probiotic strain, showed no inhibition. None of the strains was capable of inhibiting the growth of E. coli or S. enterica. The observed inhibition by bifidobacteria was related to hydrogen peroxide formation and possible production of heat-stable proteinaceous compounds. The results suggest that production of antimicrobial substances other than organic acids is not common among Bifidobacterium strains typical of elderly subjects. However, specific strains were identified which showed considerable inhibitory activity against S. aureus.