Screening of surface properties and antagonistic substances production by lactic acid bacteria isolated from the mammary gland of healthy and mastitic cows

ESPECHE, MARÍA CAROLINA; OTERO, MARÍA CLAUDIA; SESMA, FERNADO; NADER-MACÍAS, MARÍA ELENA

VETERINARY MICROBIOLOGY

Elsevier

Año: 2009 vol. 135 p. 346 - 357

0378-1135

Bovine mastitis is a costly disease in the dairy cattle. The prevention and treatment of mastitis are made by applying antimicrobial products, affecting negatively the milk quality. In the last years, the use of probiotic microorganisms to prevent infections in humans and animals is being strongly studied. A screening of surface properties and antagonistic substances production of lactic acid bacteria (LAB) isolated from mammary gland of healthy and mastitic cows was made to select potentially probiotic strains to prevent mastitis. Somatic cell count (SCC), physico-chemical and microbiological studies were performed. Pre-selected microorganisms were genetically identified. Samples from teat canal and milk (foremilk and stripping) were taken from healthy and mastitic dairy cows. Pre-selected strains were genetically identified. Compared with stripping, foremilk showed lower levels of fat and higher levels of pH, density, number of microorganisms, percentage of strains with mean and high hydrophobicty and mean autoaggregation and number of strains able to produce hydrogen peroxide and bacteriocins. The others parameters analyzed were not statistically significantly. A hundred and two LAB strains were isolated. Most of them had low degree of hydrophobicity and autoaggregation. Probably these are both characteristics from the strains isolated from cows. No correlation between this both properties was found. Antagonistic metabolites were mainly produced by strains isolated from healthy animals. Most of the pre-selected strains were identified as Streptococcus bovis and Weissella paramesenteroides. Three bacteriocins-producers were found and their products partially characterized. The results of this work are the basis for the further design of a specie-specific probiotic product able to prevent bovine mastitis.