Recommendation of a method for harmonized antimicrobial susceptibility testing of Avibacterium paragallinarum via broth microdilution and resistance monitoring of field isolates

This study aimed to develop a method for harmonized broth microdilution antimicrobial susceptibility testing (AST) of Avibacterium (Av.) paragallinarum, the causative agent of infectious coryza in chickens. For this, a total of 84 Av. paragallinarum isolates and strains were collected from 15 countries. Overall, the proposed method using CAMHB_CS_NADH for susceptibility testing with 48 h incubation time at 35 degrees Celcius in ambient air was shown to be suitable for Av. paragallinarum. Due to a variety of resistance genes detected, the development of clinical breakpoints is highly recommended.