Abstract: In order to investigate the causative agents and pathogenic characteristics of newborn piglets diarrhea outbroke in a large scale pig farm of Hubei province, the study was carried out to isolate and identify Escherichia coli from the feces of diarrheal piglets and the serotype, biochemical test and drug resistance test were conducted. The results showed that 22 strains of E. coli have been isolated from the feces samples. Serological identification results showed that 19 strains were serotyped and belonged to 5 serotypes, including O₄, O₃₈, O₅₅, O₇₆, O₁₁₉, among which the predominant serotypes were O₄, O₅₅, O₁₁₉. Drug resistance analysis showed that all of the strains were multiple drug resistance. The isolates showed the least resistance to 6 kinds of antibiotics, the most resistance to 19 kinds of antibiotics. The drug resistance rate of isolates to 20 antibiotics ranged from 13.6% to 95.5%. The most sensitive antibiotic was fosfomycin and sensitive rate reached to 77.3%. In summary, our results provided the fundamental date of serotype and drug resistance of the E.coli isolates, which provided the scientific data for clinical treatment and prevention and control of diarrhea diseases in this farm.

Key words: newborn piglet, diarrhea, Escherichia coli, serotype identification, drug resistance