Differentiation of porcine wild-type lactobacilli strains, with ERIC-PCR and PFGE band patterns included in polyphasic taxonomy

Abstract

Probiotic administration is an alternative to antibiotic supplementation in pig management. However, potential probiotic microorganisms included in foods must be well defined and correctly named, on the basis of a valid taxonomic system. The aim of the present study was to analyze band patterns generated by the polymerase chain reaction (PCR) amplification of enterobacterial repetitive intergenic consensus sequences (ERIC-PCR), obtained from porcine wild-type <i>Lactobacillus</i> strains, as a rapid alternative for genotypic characterization in polyphasic taxonomy. In the present study 36 porcine wild-type <i>Lactobacillus</i> strains were analyzed by polyphasic taxonomy which included API 50 CHL system, ERIC-PCR, and pulsed field gel electrophoresis (PFGE) band analysis, after digestion with <i>XbaI</i> or <i>SpeI</i> restriction enzymes. Polyphasic taxonomy discriminated among 23 strains of <i>Lactobacillus reuteri</i>, 12 strains of <i>Lactobacillus salivarius</i> and one strain of <i>Lactobacillus mucosae</i>. None of the tested methods was able to reliably resolve the three selected species of lactobacilli at a strain level. However, results improved considerably when ERIC-PCR results were combined with phenotypic characterization, and those results were comparable to the taxonomy that included PFGE.