In Vitro Adhesion Of Several LAB Strains And Pathogens To Puppy Intestinal Mucus

Using the soft agar method,antimicrobial activity of E01 and E16 was tested.Both of the two strains were shown to produce inhibition zone against two zoonotic pathogens.The size of the inhibitory zone was between 13mm-16mm.E01 showed the largest zone by inhibiting Escherichia coli ATCC25922.In the other hand, the DNA of E01 and El6 were extracted.The 16S rDNA sequencing was analyzed after the polymerase chain reaction(PCR).By using the BLAST program,results showed E01 was Enterococcus durans(similarity rate 97%) and E16 was Enterococcus lactis(similarity rate 99%).Usingγ-³²P-Adenosine triphosphate([γ-³²p]ATP) to label bacteria,the adhesion rate of four LAB strains,two zoonotic pathogens and one Escherichia coli originated from canine(DE) to immobilized mucus isolated from puppy different intestinal compartments in vitro were examined.All tested strains were found to have different adhesion values in different gut compartments.The adhesion values of E.faecium E01, E.faecium E16 and L.johnsonii JJB3 were significantly higher(P＜0.05) than the other two zoonotic pathogens.The most adhesive strain was E.faecium E01(15.60～25.71%) while the least adhesive strain was E.coli CVCC2060(2.88～5.74%).For study the adhesion mechanism of LAB strains and Escherichia coli,E16 and DE were pretreated with Trypsin or Sodium iodate before the adhesion experiment. Both Trypsin and Sodium iodate treatment reduced the level of adhesion of E16 whereas only Trypsin treatment reduced the adhesion of DE.For study the receptors of LAB strains and Escherichia coli,mucus were pretreated with Trypsin or Sodium iodate before the adhesion experiment.Results showed both Trypsin and Sodium iodate treatment could not reduced the level of adhesion of E16 whereas only Sodium iodate treatment reduced the adhesion of DE.At the same time,we evaluated the ability of two canine originated LAB strains (E.faecium E01 and E.faecium E16) to inhibit,displace and compete with two zoonotic pathogens(E.coli ATCC25922 and E.coli CVCC2060) in order to test the influence of the presence of the other probiotic in the adhesion pathogens to immobilized mucus isolated from puppy jejunum in vitro.It had been seen in the results that two canine originated LAB strains could significantly reduce(P＜0.05) the adhesion of two zoonotic pathogens in inhibition and displacement way.E.faecium E01 and E.faecium E16 have high adhesion ability and may be regarded as potential probiotics.