Characterization Of Pathogenic Escherichia Coli Isolates From Gooses In Yancheng

Colibacillosis in gooses is an important infectious disease, which can causeserious economic loss in goose keeping. The purpose of this study was to investigate thepresence of Escherichia coli isolated from geese and dead embryonated eggs in 10counties of Yancheng. The epidemiologic survey, analysis and drug susceptibility ofgoose E. coli isolates in Yancheng will provide useful information for general preventionand control of this disease.Two hundreds ninety three isolates were obtained from 304 samples of geese withtypical signs and lesions of colibacillosis and 356 samples of dead embryonated eggsuseing Maconkey agar plates. The results of Gram staining, microscopic examination andbiochemistry test indicated that 256 strains of isolates were E. coli, and the isolating ratewas 87.4%. The 21 serogroups of 197 isolates were identified by plate agglutination test,and O₁, O₁₀₇, O₁₄₁, O₉, O₇₈, O₇, and O₃₆ were the major serogroups, which accounted for142 isolates. We found that 85 isolates (43.1% of all isolates) belonged to the first 3serogroups. These results indicated that serogroups O₁, O₁₀₇ and O₁₄₁ were prevalent andthe distribution of serogroups may be diverse in this area.In pathogenicity test, 51 isolates selected from 21serogroups were pathogenic to1-day-old geese. Among isolates from prevalent serotgroups, 77.8% of isolates showedhigh pathogenicity to 1-day-old geese, while 16.7% and 5.5% of isolates showed middle and low pathogenicity to 1-day-old geeses. There was no significant difference inpathogenicity, although the isolates were from 10 different counties and distributed in 21serogroups. The result suggested that there was no relationship between pathogenicityand regions or serogroups.To guide the clinical medication, the susceptibility to common antibiotics of 95isolates from goose was determined. 69-81% of isolates was sensitive to Enrofloxacin,ciprofloxacin and Kanamyein. 29-45% of isolates was sensitive to Furaxone, Florfenicol,Gentamycin, Oxybicycline and Ceftiofur. All of the isolates have the lowestsusceptibility to Streptomycin, Trimethoprim, Ampicillin, Doxycycline and Penicillin. Inorder to prevent and control avian colibacillosis, selection of sensitive antimicrobialswith susceptibility test was recommended.