| Clostridun Perfringens is a Gram-positive anaerobic bacterium that is widely found in the natural environment and is partially pathogenic and is the cause of many diseases.C.Perfringens can cause diseases such as lamb dysentery and enterotoxemia,which seriously endangers the development of the sheep industry.In recent years,with a large number use of antibiotics in large-scale farms,C.Perfringens' multi-drug resistance has emerged and become a public concern,but there are few studies on the resistance of Clostridium perfringens.In this study,sheep source samples were collected from Shaanxi,Ningxia and Qinghai provinces.The traditional microbiology and molecular biology methods were used to isolate and identify C.Perfringens and toxin genes,and to know the C.Perfringens epidemic toxins in the three provinces.The MIC and related drug resistance of the isolated strains were tested to provide information for the prevention,treatment and drug resistance mechanism of Clostridium perfringens in sheep.The study obtained the following results:1.From the 260 samples collected from Shaanxi,Qinghai and Ningxia,61 strains of C.Perfringens were isolated,including 12 strains in Shaanxi,4 strains in Ningxia and 45 strains in Qinghai.2.The four toxin genes of ?,?,? and ? were detected.The the type A was 43 strain,the positive rate was 78.6%;and the type D was 18 strain,the positive rate was 29.5%,Therefore,it can be speculated that the A and D strains have gradually become epidemic strains of Clostridium perfringens.Among the 61 isolates of Clostridium perfringens,the positive strains of CPE and ?2 toxin were detected as 4 strains and 29 strains,respectively,and the positive rates were 6.5% and 47.5%,respectively.This result showed high detection of ?2 toxin.It can be speculated that it plays an important role in the pathogenesis of Clostridium perfringens.3.For 61 strains of C.perfringens isolates,The drug sensitivity test of 27 commonly used antibacterial drugs was carried out on 61 strains of C.perfringens.The results of drug susceptibility test showed that sulfa resistance was the strongest,and that flavomycin,gentamicin,erythromycin,clinda,Magnesium,and tetracycline have different degrees of drug resistance,while ?-amide,doxycycline,enramycin,nosiheptide,and bacitracin are more sensitive.The strains isolated from Shaanxi were more resistant to erythromycin,gentamicin and clindamycin than Qinghai and Ningxia,while the sulfa-resistant strains of the three isolates were severe.The common resistance genes of 61 strains of C.perfringens isolates were amplified.The detection rate of sulfonamide sul2 gene was 50.81%,and the detection of gentamicin aph(3')-?-F gene was detected.The detection rate was 21.31%,the detection rates of tetracycline resistance genes tetA(P)and tetB(P)were 19.67% and 14.75%,respectively,while the resistance genes of linacamide and macrolide were ermA,ermB and ermC.The detection rate was low,1.63%,4.91%,and 6.55%,respectively;this may be related to drug resistance.Among them,multi-drug resistance genes are also common.There are 13multi-drug resistant strains,and more than 3 drug-resistant genes can be detected.6 strains can detect more than 4 drug-resistant genes,and 3 strains can detect 5 drug-resistant genes.These results show that multi-drug resistance genes have begun to spread in C.perfringens,which shows that the use of standardized antibiotics,strengthening drug resistance mechanisms and new veterinary drugs are urgently needed. |
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