Virulence and Resistance of Pseudomonas aeruginosa Isolated from Poultry in Brazil

Pseudomonas aeruginosa is an opportunistic pathogen commonly associated with infections in hospitalized and immunocompromised patients due to its virulence and antimicrobial resistance. In the poultry industry, it has been associated with hatchery mortality. This study aimed to characterize P. aeruginosa isolated from pipped eggs, one-day-old chicks, and broiler carcasses obtained from a slaughterhouse in São Paulo state, Brazil. Nineteen strains of P. aeruginosa were selected and their virulence genes were amplified via PCR. Clonality analysis was performed using BOX-PCR, and three strains were selected for whole-genome sequencing (WGS). All isolates carried aprA, plcH, plcN, lasA, lasB, lasI, lasR, rhlAB, and phzH. The exoA gene was detected in 73.7% of strains, while algD was present in 21.1%. The exoY and exoT genes were present in 94.7% of strains (18/19), whereas exoS was present in 47.4% (9/19). None of the isolates harbored the exoU gene. BOX-PCR and phylogenetic analyses revealed diverse clonal patterns. The sequenced strains were classified as O3 ST116, O2 ST1649, and O3 ST1744. The presence of virulence and antimicrobial resistance determinants in poultry-associated strains underscores the need for surveillance, as these isolates may represent a source for transmission of P. aeruginosa to humans. Our findings highlight the importance of monitoring P. aeruginosa within poultry production and emphasize the value of genomic approaches to understand its diversity, evolution, and public health risks.