Resistant Nalysis And Rational Drug Recommendations Of 34 Calves With Diarrhea Caused By E. Coli.

Calf diarrhea disease is caused by E. coli enterotoxigenic what can lead to severe diarrhea and even death. Tt brought huge economic losses for the dairy industry, but also cause a great threat to human health.Abuse of antibiotics in clinical is worsening and it lead to an increase in drug-resistant strains and broadening of resistance patterns.Many commonly used antibiotics has completely lost the basic effect. Therefore, the investigation and analysis of the country’s calf diarrhea drug resistance of E. coli has an impertant significant for the prevention and control of calf diarrhea.This study includes the E. Coli resistance of drug case and the investigation of related resistance genes.Using Kirby-Bauer disk diffusion method,test the drug resistance and multidrug-analyzed of 34 E. coli diarrhea isolates in calves that isolated from large-scale dairy farm of Chinese northern part to 22 kinds of commonly used antibiotics.The results is, resistance rates of idoxycycline and clindamycin to 34 calf diarrhea E. col up to 100%.Resistance rates above 80 percent have five kinds,respectively, ampicillin, streptomycin, azithromycin,doxycycline, trimethoprim-sulfamethoxazole.Sensitivity rate of nitrofurantoin,cephalosporin plug oxime, polymyxinB is more than 50%.Sensitivity rate of Fosfomycin reached 97.06%,therefore,fosfomycin is most sensitive.In this study, I detect related resistance genes of quinolones, aminoglycosides, β-lactams, tetracycline, chloramphenicol, sulfonamides by PCR method. I tested GyrA, GyrB and ParC gene of quinolones,the positive rates were 70.59%, 67.65%, 61.76%.There are 27 isolates are resiatant to quinolone,the positive rate of which three genes respectively 74.07%, 81.48%, 66.67%.I tested aadA, aadB and Aph(3)-II gene of aminoglycosides,the positive rates were 44.12%、23.53%、61.76%.There are 33 isolates are resiatant to aminoglycosides,the positive rate of which three genes respectively 42.42%、24.24%、72.72%.Of which one was showed no resistance phenotype strains to aminoglycoside but was detected aadA gene. I tested blaTEM gene of β-lactams,the positive rate was 61.76%.I tested floR、cat gene of chloramphenicol,the positive rates were 52.94%、32.35%. Detection rate 34 E. coli also carry two genes is 11.76%.I tested sul2、sul3 gene of sulfa,the positive rates were 52.94%、70.59%.I tested tet(B)、tet(D) gene of tetracycline,the positive rates were 35.29%、26.47%.Based on these test results,the northern part of the dairy calf diarrhea of E. coli in most areashasproducedseriousresistance.andhasdetecteditsassociatedresistancegene.meanwhileexperimentsalsoconfirmedthespreadandproliferationofdrug-resistantgenesleadtoincreasednumberofresistantisolates.theincreasingofmulti-drug-resistantstrainshasbroughtgreatdifficultiestoclinicaltreatment.thisstudyprovidethedrugofclinicalchoiceandhowtouseantibioticsreasonablelyforthenorthernregion.