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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Publications at this Location » Publication #422526
Research Project: Elucidating the Factors that Determine the Ecology of Human Pathogens in Foods

Location: Produce Safety and Microbiology Research

Title: Mobile genetic elements drive the evolution and multidrug resistance of Salmonella Infantis along the United States poultry production line

Author
item Zhang, Yujie
item Chu, Mackenna
item SAMALA, SANGHVI - Hispanic Association Of Colleges & Universities (HACU)
item Salvador, Alexandra
item Liao, Yen-Te
item Wu, Vivian

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/5/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: N/A

Technical Abstract: Salmonella is the primary enteric pathogen related to foodborne illnesses worldwide, posing significant public health concerns. Amongst over 2000 Salmonella serotypes, Salmonella Infantis (S. Infantis) ranks among the top Salmonella serotypes implicated in foodborne outbreaks, with thousands of reported cases annually in the United States. Moreover, the incidence of S. Infantis infections has spread rapidly worldwide, where more than 50% of isolated S. Infantis strains have developed antibiotic resistance. Previous studies have shown that antibiotic resistance genes (ARGs), particularly those carried on by plasmids, contribute to the persistence and spread of multiple-drug resistant (MDR) Salmonella strains in various environments. However, the information regarding the multidrug resistance and spread of S. Infantis is scarce. Hence, the objectives of this study were to characterize antibiotic-resistant S. Infantis isolated from the poultry production line in the United States and to examine the correlation between mobile genetic elements and bacterial resistome evolution. A total of 9 S. Infantis strains were isolated from poultry production lines in 2022, including comminuted chicken, raw intact/nonintact chicken, and chicken carcass. These strains were further subject to antimicrobial susceptibility tests and whole genome sequencing (WGS). The complete bacterial genome showed that all isolates had a dsDNA chromosome with a GC content of 52.3% and an average genome size of 4,730 kb, belonging to sequence type 32. Additionally, most strains showed phenotypic resistance to four or more antibiotics, except for S. Infantis 4897. The genomic characterization of S. Infantis isolates revealed that each strain contained one IncFIB mega-plasmid with lengths from 289 to 327 kb. Five or more ARGs were detected in each strain, of which most ARGs were located in the mega-plasmids and bordered by diverse mobile genetic elements, including transposons, integrons, and prophages. Moreover, the majority of WGS-derived ARG profiles had concordant phenotypic traits. Overall, our study demonstrates the genomic features and antimicrobial resistance profiles of S. Infantis strains from the poultry production lines in the United States, indicating the potential of mobile genetic elements-driven S. Infantis resistome development.