Virulence potential of Enterococcus gallinarum strains isolated from selected Nigerian traditional fermented foods

Abstract

Five Enterococcus isolates from some Nigerian traditional fermented foods were identified as Enterococcus gallinarum by using phenotypic and genotypic tests. Safety properties such as antibiotic susceptibility, virulence gene detection, haemolysin, gelatinase and bacteriocin production were determined using standard methods. There was no resistance to clinically relevant antibiotics. Virulence gene for collagen binding antigen and aggregation substance were detected in 60% of the E. gallinarum strains; while surface adhesin was detected in 20%, but none of the strains had cytolysin activator and gelatinase. Phenotype characterizations of the E. gallinarum isolates indicated that none of the isolates produced haemolysin and gelatinase. Enterococcus gallinarum C103 and U82 had no antimicrobial activity against all the selected bacteria pathogens while E. gallinarum W184, T71 and W21 were active against some of the indicator bacteria pathogens. Only E. gallinarum T71 and W21 showed broad spectra of antimicrobial activity. Combination of virulence factors did not appear in these food isolates. Therefore, these strains particularly the two strains with high spectra of antimicrobial activity could be exploited as functional starters in foods.

Keywords

• virulence genes
• haemolysin
• gelatinase
• antibiotic susceptibility and antimicrobial activity