Molecular Insights and Phylogenetic Analysis of Acinetobacter baumannii Carrying Carbapenem Resistance Genes in Broiler Chickens: An Emerging Threat to Human Health

Abstract

Acinetobacter baumannii remains a significant nosocomial infectious agent, with its ability to acquire antimicrobial resistance posing a global public health concern. Over time, substantial knowledge has been amassed regarding A. baumannii in human clinical cases. Recently, research has shifted to non-human A. baumannii. Therefore, the current work aimed to investigate the occurrence of A. baumannii carrying carbapenem resistance genes in broiler chickens via molecular detection and its public health significance. Two hundred cloacal swabs were collected from broiler chickens and grouped into 40 pools. DNA extraction was conducted on these pools, followed by molecular detection of the A. baumannii blaOXA-51-like gene. Among the 40 pools, 31 (77.5%) tested positive for the blaOXA-51-like gene and were further screened for additional carbapenemase genes, including blaOXA-58, blaOXA-23, and blaOXA-24. The blaOXA-58 gene was identified in eight pools (25.8%), whereas blaOXA-23 and blaOXA-24 were not detected. Subsequently, partial DNA sequencing was performed on two PCR amplicons of the A. baumannii blaOXA-51-like gene derived from broiler chickens, followed by a phylogenetic analysis. The analysis revealed genetic similarity between the A. baumannii sequences obtained in this work and those retrieved from humans, birds, animals, and environmental sources. In conclusion, the occurrence of A. baumannii harboring genes coding for carbapenem resistance in broiler chickens highlights a potential new path of transmission, which may require further investigation to better understand the dynamics of transmission and to guide effective strategies for preventing and controlling A. baumannii infections.