<i>In Vitro</i> Characterization of Cell Surface Properties of 14 Vaginal <i>Lactobacillus</i> Strains as Potential Probiotics

Abstract

Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. Human-origin Lactobacillus is a preferable source of probiotic bacteria. This study screened 14 vaginal Lactobacillus strains as probiotic candidates by investigating probiotic-related cell surface characteristics including cell surface hydrophobicity (CSH), Lewis acidity/basicity, autoaggregation, and biofilm formation. Moderate to high CSH and autoaggregation, high basicity and low acidity were prevalent in the 14 tested strains. Biofilm formation varied in a large range among the 14 tested strains. CSH showed a high correlation with Lewis acidity and autoaggregation, while Lewis acidity was highly correlated with autoaggregation and biofilm formation. Four strains were selected as promising probiotic strains. This study was the first one to compare antibiotic sensitivity between biofilm-forming cells and planktonic cells of Lactobacillus species, and found that biofilm-forming cells of a L. fermentum strain had a significantly higher survival rate than planktonic cells in cefotaxime, cefmetazole and tetracycline, but were as sensitive to oxacillin and ampicillin as planktonic cells were.