Isolation And Some Biological Characteristics Identification Of Escherichia Coli Caused Calves Encephalitis

Intestinal pathogenic E. coli(Ex PEC) is one of the main pathogens cause encephalitis and septicemia in infants, but livestock related encephalitis caused by bacteria of mass pathology have not been reported. December 2013, a large-scale dairy farm in Xinjiang Shihezi a week or so calves have occurred with the death of the main symptoms of encephalitis, 13 calves had died, the dairy cause greater economic losses, as identify and determine the cause of the encephalitis dairy calves major pathogen, epidemiology, clinical examination, and on the basis of anatomy, brain tissue and liver tissue collected dead calves were isolated and identified pathogen. Using diseased smear staining, culture characteristics, biochemical tests, O antigen serotypes measured pili PCR testing, susceptibility testing, animal testing, and brain infection histopatholo-gical observation. Results are as follows:1.A dead calf cerebrospinal fluid isolates were gram-negative bacteria, rounded at both ends of the short rod, cultural characteristics and biochemical identification results in full compliance with the biological characteristics of E. coli;2.Isolates of E. coli β hemolysis was carrying K99-STa gene, enterotoxigenic E. coli feature, O serotype O161, is a rare serotype;3.Isolates to ampicillin, gentamicin, amoxicillin, ciprofloxacin, norfloxacin, enrofloxacin, kanamycin, chloramphenicol, tetracycline, streptomycin, cotrimoxazole, cephalothin resistant to amikacin, cefazolin and neomycin sensitive, indicating that multi-drug resistant isolates have;4.Inoculate rabbits and mice four isolates, three days after the death of infected rabbits, mice died within 24 hours of infection, by the isolation and culture of bacteria recovered from the death of brain tissue of mice after inoculation of bacteria biochemical identification identified as E. coli indicating a strong pathogenic isolates, can invade brain tissue with intestinal infection characteristics;5.by paraffin histological observations, independent of morbidity and mortality in the calves and rabbits experimentally infected brain tissue vascular congestion, neuronal cell vacuolar degeneration and necrosis, degeneration and necrosis within the meninges have a lot of neutrophil infiltration, presents non encephalitis encephalitis changes coli isolates showed calves and rabbits can cause brain damage;Pathogen detection results show that dairy calves encephalitis caused by the death of the Department to have a portable K99-STa hemolysin virulence factors, O serotype O161 E. coli infection. Parenteral suspected pathogenic E. coli. Results-oriented diagnosis disease etiology provide basis for further research to explore the biological characteristics of encephalitis caused by animal E. coli test provides valuable information.