Identification and antimicrobial resistance of isolated bacteria from trachea of laying hens

Bacterial respiratory problems cause economic losses due to production decreases and the increasing cost of antibiotic treatment. In poultry production, they are the leading cause of death in laying hens. The presence of pathogens implies a distribution in the production units, and their identification by biochemical tests allows the characterization at the species level and its adequate treatment. The present study aimed to identify the bacteria isolated from the trachea of laying hens and determine their antibiotic resistance profile. In an intensive production farm, trachea samples were taken from hens; the bacterial detection was carried out with isolation, colonial and microscopic identification, and biochemical tests; the antimicrobial susceptibility test was also determined. Thirty-two isolates corresponding to five types of bacterial colonies with the morphology of cocci and Gram-positive bacilli (Staphylococcus aureus, Staphylococcus epidermidis and Corynebacterium spp) and Gram-negative coccobacilli (Pasteurella multocida and Gallibacterium anatis) were obtained. S. aureus, S. epidermidis, and Corynebacterium spp showed resistance to glycopeptides (100%), in addition to P. multocida and G. anatis, to ampicillin (beta-lactams) and quinolones (100%). The isolated bacteria showed antibiotic resistance and multi-resistance, with implications for poultry farming and public health.