Epidemiological investigation and drug resistance analysis of avian pathogenic Escherichia coli (APEC) of Wenchang chickens in Hainan, China.

Type O8 is the most prevalent serotype of APEC isolated from Wenchang chicken embryos (Hainan, China).The isolates were more than 90% resistant to erythromycin, amoxicillin, ampicillin, and tetracycline.19.2% of the isolates were multi-resistant to more than 14 antibiotics.APEC of the same serotype isolated from Hainan Wenchang embryos have close relationships in the evolutionary tree of the core genome.