Abstract: To understand drug resistance of Escherichia coli （E.coli） isolated from the production chains of main animal food，using trace dilution method recommended by clinical and laboratory standards institute CLSI broth，350 strains E.coli isolated from the production chains of pork，eggs and chickens were examined for sensitiveness against 10 kinds of antimicrobial agents （combination）. The results showed that 350 strains E.coli were mostly resistant to tetracycline （82.0%），followed by resistance to trimethoprim/sulfamethoxazole （75.4%），and the gentamycin drug resistant rate （26.9%）was the lowest. Despite the different origins of E.coli for the vast majority of these drugs were basically consistent， the resistance rate of the strains from different segments of animal food production chain was different.76.2% （267 strains） of the isolates were multi-drug resistant strains，the most of which were the eight kinds of drug-resistant strains （17.7%）. The whole test strains had 108 kinds of drug spectra， the spectra of E.coli isolated from the production chains of pork，eggs and chickens were 40，46 and 55，respectively，whereas the advantage drug resistance spectra were not obvious. The main drug resistance spectra included NAL-CIP-AMP-AMC-CEF-SPT-GEN-SXT-TET （21/350）， TET （20/350）， NAL-CIP-AMP-AMC-CEF-SPT-SXT-TET（16/350）， NAL-CIP-AMP-CEF-FLO-SPT-SXT-TET（16/350） and SPT-SXT-TET（15/350）. The results suggested the drug resistance of E.coli from the production chain of main animal food was serious，so it was necessary to strengthen the continuous monitoring and control.

Key words: Escherichia coli; animal food; production chain; drug resistance; drug-resistant spectra