Probiotic properties of lactic acid bacteria isolated from human milk

Abstract

Aim: The objective of this study was to identify and characterize lactic acid bacteria isolated from human milk, with an emphasis on their probiotic properties. Methods and Results: The strains were tested for their ability to inhibit growth of Enterococcus faecalis, Salmonella enterica subsp. enterica serotype Enteritidis, Listeria monocytogenes, Staphylococcus aureus and Escherichia coli, as well as for susceptibility to antimicrobial agents and for acid pH and bile salt tolerance. Gram-positive and catalase-negative were selected and identified as Enterococcus (83·3%) after sequencing the 16S rDNA gene. All the isolates inhibited growth of Ent. faecalis and S. serotype Enteritidis, 97% inhibited growth of L. monocytogenes and Staph. aureus and 78·8% inhibited growth of E. coli. Most of the isolates were resistant to gentamicin (50%) and vancomycin (47%). Twelve isolates grew when subjected to pH 3·0 and 0·1% bile salts. At lower pH (2·5–2·0), Ent. faecalis F1 and Weissella confusa F8 were more efficient. Conclusion: It was possible to isolate from human milk the lactic acid bacteria with potential for use as probiotics. Significance and Impact of the Study: Lactic acid bacteria isolated of nursing mothers have probiotic properties.