Isolation of Drug-Resistant <i>Gallibacterium anatis</i> from Calves with Unresponsive Bronchopneumonia, Belgium
Laura Van Driessche, Kevin Vanneste, Bert Bogaerts, Sigrid C. J. De Keersmaecker, Nancy H. C. Roosens, Freddy Haesebrouck, Lieze De Cremer, Piet Deprez, Bart Pardon, Filip Boyen
Abstract
Gallibacterium anatis is an opportunistic pathogen, previously associated with deaths in poultry, domestic birds, and occasionally humans. We obtained G. anatis isolates from bronchoalveolar lavage samples of 10 calves with bronchopneumonia unresponsive to antimicrobial therapy. Collected isolates were multidrug-resistant to extensively drug-resistant, exhibiting resistance against 5–7 classes of antimicrobial drugs. Whole-genome sequencing revealed 24 different antimicrobial-resistance determinants, including genes not previously described in the Gallibacterium genus or even the Pasteurellaceae family, such as aad A23, bla CARB-8 , tet (Y), and qnr D1. Some resistance genes were closely linked in resistance gene cassettes with either transposases in close proximity or situated on putative mobile elements or predicted plasmids. Single-nucleotide polymorphism genotyping revealed large genetic variation between the G. anatis isolates, including isolates retrieved from the same farm. G. anatis might play a hitherto unrecognized role as a respiratory pathogen and resistance gene reservoir in cattle and has unknown zoonotic potential.