Study On Isolation, Identification, Drug Sensitive Test And Control Efficiency In Vivo Of Escherichia Coli In Tai'an Area

In order to control colibacillosis effectively, we take pathogen isolation and identification about the submitted suspected colibacillosis cases. We take comparison tests about the single drugs and compound drugs acting on isolated bacteria as well as tests about drugs resistance to observe the speed and extent of drugs resistance after repeated contacting with some drugs in vitro, and provide theoretical basis for taking medicine in veterinary clinical. This experiment has ten typical colibacillosis cases isolated from chickens which have typical pericarditis in Taian. Then we take series-experiments on pathogenic characteristic. Make Bacterial direct smear, Gram stain microscopy shows that Gram-negative, showing short, straight rod-shaped.The isolates formed brick-red sporulation on the MacConkey agar, round elevated, smooth and humid, the edge of a small colony neat. In eosin methylene blue agar ,it forms purplish black, metallic luster of small colonies. Series of biochemical test results fully in line with biochemical characteristics of E. coli, initially prove that the isolated bacteria are E. coli. The drug sensitive test results show that the isolated colibacillosis are sensitive to Neomycin﹑Florfenicol﹑Azithromycin﹑Cefotaxime(Cephalosporin piperazine shu)﹑Fosfomycin sodium, and have a better effect on compound drugs,especially combination of neomycin would greatly reduce costs and achieve good economic.The results have provided scientific basis for choosing drugs that cure E.coli clinically in this region.But if we take these drugs for continous subculture of 8 times, then they will turn high sensitivity and middle sensitivity to low sensitivity.It is suggested that susceptibility tests can come into being the bacterial strains that bearing medicine easily.If we do not deal with the resistant strains improperly,it will make a significant potential threat to the health of livestock and poultry production industry and the human health and safety . To verify the consistent about the effects in vivo and in vitro, we choose part of sensitivity drugs and make them act on artificial-infection chickens,and give a proper assessment about the relevance between vivo experiments and vitro experiments to instruct veterinary clinical medicine better. The results show that the oral treatments about Flofeniclo and cefotaxime have a significant effect on curing artificial infection of E.coli,consistent with the result of susceptibility tests in vitro .Ciprofloxacine has a low sensitivity in vivo experiment which shows that it is suitable for oral use. Amikacin in vitro and in vivo susceptibility test results are inconsistent,although in vitro susceptibility test for high sensitivity,oral alone is not the desired effect.In summary, the susceptibility tests can be an important basis about curing colibacillosis in clinical treatment, but we can't give a blind dosage without selection.