Objective To understand the current drug resistance status and bacterial multilocus sequence typing （MLST） of human and avian Campylobacter jejuni in Jinshan District， Shanghai.

Methods Fecal samples were collected from diarrhea patients in the annuity mountainous area from 2021 to 2022， and poultry and related samples were collected from 2 poultry farms in the Jinshan area for detection of C. jejuni. Minimal inhibitory concentration （MIC） drug sensitivity test was performed on the detected C. jejuni， and some strains were selected for whole genome sequencing and MLST analysis.

Results A total of 823 samples of diarrhea disease were collected， and 32 strains of C. jejuni were detected， with a detection rate of 3.89%. Out of 600 poultry related samples， 62 strains of C. jejuni were detected， with a detection rate of 10.33%. Human multidrug resistance reached 93.75% （30/32）， while avian multidrug resistance reached 100.00%（62/62）. The top four drug resistance rates of human and avian C. jejuni were azithromycin （100.00% from humans and 100.00% from birds）， naphthoic acid （93.75% from humans and 87.10% from birds）， ciprofloxacin （90.63% from humans and 98.39% from birds）， and tetracycline （84.38% from humans and 98.39% from birds）. The relatively low resistance strains of human derived C. were erythromycin， chloramphenicol， and thalithromycin. The relatively low resistance strains of avian C. jejuni were erythromycin， clindamycin， and flufenicol. MLST analysis showed that the selected 16 strains of bacteria were divided into 9 ST types， among which the evolutionary relationship of avian C. jejuni was relatively concentrated， while human C. jejuni was relatively dispersed. It was found that one strain of avian C. jejuni was closely related to two strains of human C. jejuni.

Conclusions C. jejuni infection is severe in patients with diarrhea in this region， with a detection rate second only to salmonella and Vibrio parahaemolyticus. C. jejuni infection in poultry is relatively common， and both are highly resistant. Therefore， monitoring and control should be strengthened. MLST analysis shows new ST types in both avian and human sources of C. jejuni， indicating the emergence of new mutations that require continuous monitoring to avoid the epidemics caused by new strains. The isolated strains with close genetic relationships between avian and human sources reveal the evidence of the spread of C. jejuni from poultry to humans. Therefore it is necessary to strengthen the monitoring of C. jejuni in relevant samples from breeding farms.