| Tureperella pyogenes (T. pyogenes) is a well known opportunistic pathogen causing a variety of suppurative infections, including metritis, mastitis, liver abscessation, pneumonia, arthritis and endocarditis in sheep, cow and swine. Antibiotic resistance in T. pyogenes has been reported in many studies, and causing an increasing concern recently. Many mechanisms contribute to antibiotic resistance in T. pyogenes, such as the transposon, plasmids and other mobile genetic elements, the mobile genetic elements play an important role in antibiotic resistance, there have been reports focusing on Chinese traditional herbs decrease or inhibit antibiotic resistance in bacteria by influence on the mobile genetic elements. This study aimed to study the correlation between antibiotic resistance in T. pyogenes and the transposon, at the same time the influence of Luteolin on the transposon in T. pyogenes, to illustrate the role of transposon in T. pyogenes antibiotic resistance, which will be beneficial in developing Luteolin as an innovative antimicrobial agent.The PCR method was used to detect transposon gene, including IS26, tnp513, tnpA, tnpU, tn1721 and merA, among 34 isolates, and analyzed the correlation between drug resistance and transposon in T. pyogenes.The results indicated that three kinds of transposons(tnpA、IS26 and tnp513) were deceted in the isolates, the decection rate is 41.18%,61.76% and 17.65%, respectively. There was no detection of transposon tnpU, tn1721 and merA among these isolates. The detection rate of transposon increases as the antibiotic-resistant phenotype increase. All the isolates were resistant against the sulfanilamides and polypeptide, which indicated there was a significant correlation between drug-resistance and Transposon tnpA, while Transposon IS26 and tnp513 had no significant correlation with drug resistance phenotype in these isolates.Then, we detected the minimum inhibiting concentrations (MICs) of erythromycin and tylosin among isolates carrying Transposon tnpA treated by various concentrations and times of Luteolin; at the same time, the expression of tnpA (by real time PCR) and antibacterial activity were measured when treated at sub-inhibiting concentration. The results indicated that Luteolin showed significant antimicrobial activity against isolates carrying tnpA, and when combined with erythromycin and tylosin, a synergistic effect was observed; the MICs against T. pyogenes became 1/4-1/16 and 1/2-1/64, respectively when treated with Luteolin for 30h and 36h respectively, the isolates became more sensitive to erythromycin and tylosin. The nucleotide sequence got no mutation after treated by Luteolin, but the expression of tnpA mRNA decreased in all isolates. The MICs decreased as the expression of tnpA mRNA decreased, which indicated that Luteolin may decrease the antibiotic resistance in T. pyogenes mediated by decreasing the expression of tnpA mRNA.The study focused on the antibiotic resistance in T. pyogenes, and analyzed the correlation between antibiotic resistance in T. pyogenes and transposons, which will be useful in illustrating the mechanism of antibiotic resistance in T. pyogenes, meanwhile the influence of Luteolin on tnpA was measured, and this study will provide an insight to develop Luteolin as the innovative antimicrobial agent. |
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