The Prevalence And Plasmid Correlation Studies About Pig Source ESBLs-producing ETEC In Jiangxi Province

Recently, it is popular to produce Extended Spectrum Beta-Lactamases(ESBLs) in Escherichia coli from swine and makes bacterial multidrug resistance, which makes the prevention and control to the drug resistant E. coli challenging. Enterotoxigenic E. coli(ETEC) is one of the most common pathogenic E. coli in swine. The study on popularity of ESBLs in swine ETEC and the drug resistance mediated by it is significant for Jiangxi,the major pig producing province in China.In this study, 146 strains of E. coli isolated from rectal swab of diarrhea piglets in Jiangxi industrialized pig farms were used as tested materials. Firstly, ETEC and producing ESBLs ETEC were respectively identified by the method of PCR and double-disk test, and determined by drug sensitive test. Results were as follows:(1)detection rate of ETEC was 65.07%(95/146), producing ESBLs ETEC was 20.55%(30/146);(2) the drug resistance rate of ETEC to lincomycin, tetracycline, trimethoprim,cefalexin and amoxicillin all exceed 90%, which were 100.00%、94.74%、94.74%、91.58%and 90.53% respectively. ETEC was sensitive to imipenem, cefoxitin, ceftazidime,cefepime and aztreonam;(3) The drug resistance rate of producing ESBLs ETEC toβ-lactam antibiotics was significantly higher than non-ESBLs ETEC in general and was similar to non-β-lactam antibiotics. Secondly, ESBLs classification, plasmid classification and bacteria evolution grouping of producing ESBLs ETEC were studied by the method of PCR. Results were as follows:(1) TEM, CTX-M, SHV and OXA ESBLs were all checked out and their detection rate were 70.00%, 63.33%, 16.67% and 13.33%, respectively;(2)there were 8 different types of plasmid replicons checked out, including FIB, I1, HI2, FIA,Y, FIC, FrepB and N. FrepB, FIB and II were the most frequent type plasmid in producing ESBLs ETEC, which occupied 66.67%, 60.00% and 46.67% respectively. The detection rate of different plasmid replicons of non-producing ESBLs ETEC was about 33.33 to53.33% other than the 13.33% of N and I1;(3)Bacterial evolution grouping study found that most of producing ESBLs ETEC(46.67%, 14/30) was group A ETEC; there were no significant difference in detection rate of groups to non-producing ESBLs ETEC. Finally,translated ESBLs positive plasmid to Top10 cell, thereby performing drug sensitive test for transformant. Study found that a total of 19 strains of transformant were obtained, the transformants kept all or part of the drug resistance of the original strain.The study tamped the basic research of producing ESBLs ETEC from swine,enriched the study data of producing ESBLs ETEC in Jiangxi, layed a theory foundation of further study on producing ESBLs ETEC drug resistant mechanism and drug resistant repair.