Korean J Vet Res.  2012 Sep;52(3):169-176.

Isolation, characterization, and evaluation of Bacillus thuringiensis isolated from cow milk

• Kweon CH
• Choi SY
• Kwon HY
• Kim EH
• Kang HM
• Moon JS
• Jang GC
• Lee HS
• Kang SW
• Kim JM
• Pyo S
• Rhee DK

Abstract

Probiotics colonize the intestines and exert an antibacterial effect on pathogens. Therefore, probiotics could be used as a preventive agent against lethal infections. To isolate probiotic microorganisms, 116 bacterial strains were isolated from healthy cow's milk and were subjected to Gram-stain, morphology and biochemical analyses, Vitek analysis, and 16S rRNA analysis. One of the strains identified as Bacillus (B.) thuringiensis 87 was found to grow very well at pH 4.0~7.0 and to be resistant to high concentrations of bile salts (0.3~0.9% w/v). B. thuringiensis was susceptible to the antibiotics used in the treatment of bovine mastitis, yet it exhibited an antimicrobial effect against Staphylococcus (S.) aureus 305. Moreover, it protected mice from experimental lethal infections of E. coli O55, Salmonella typhimurium 01D, and S. aureus 305 through a significant induction of interferon-gamma, even at four-week post-administration of B. thuringiensis. Although oral administration of B. thuringiensis 87 did not provide significant protection against these lethal challenges, these results suggest that B. thuringiensis 87 could be a feasible candidate as a probiotic strain.

Keyword

Bacillus thuringiensis; interferon-gamma; probiotics

MeSH Terms

Administration, Oral
Animals
Anti-Bacterial Agents
Bacillus
Bacillus thuringiensis
Bile Acids and Salts
Cattle
Colon
Female
Hydrogen-Ion Concentration
Interferon-gamma
Intestines
Mastitis, Bovine
Mice
Milk
Probiotics
Salmonella typhimurium
Sprains and Strains
Staphylococcus
Anti-Bacterial Agents
Bile Acids and Salts
Interferon-gamma