Abstract: In order to detect the main bacterial pathogens and analyze the drug resistance for providing therapeutical guidance for drug administration,4 stains were isolated from death chickens of a breeding chicken farm in Qinhuangdao area.All 4 isolates were identified by morphological characteristics,biochemical test,immunofluorescent staining,amplification of 16S rRNA genes by PCR,sequence analysis and drug susceptibility test.The results showed that all 4 isolates were gram-negative,bacillus brevis with green fluorescent,and the sequence of 16S rRNA gene of isolates were analyzed and test results showed that specific amplified band was consistent with the expected size.The isolated bacteria were identified to be Pseudomonas aeruginosa.Results of drug susceptibility test indicated that the bacterial isolates were highly sensitive to gentamycin,amikacin,spectinomycin,ceftazidine,ceftriaxone,levofloxacin,enrofloxacin,florfenicol,polymyxin B and fosfomycin,intermidiate sensitive to tetracycline and doxycyclin,resistant to neomycin,cefotaxime,cephalothin,amoxicillin,ampicillin,erythromycin,trimethoprim-sulfamethoxazole and oxygen sulfamethoxazole isoxazole.The results suggested that the resistances of Pseudomonas aeruginosa isolates to commonly used antibiotics were serious.So antibiotics should be reasonably selected based on the result of drug susceptibility test in this farm.

Key words: chicken; Pseudomonas aeruginosa; isolation and identification; drug susceptibility test