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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Egg and Poultry Production Safety Research Unit » Research » Publications at this Location » Publication #416172
Research Project: Reduction of Foodborne Pathogens and Antimicrobial Resistance in Poultry Production Environments

Location: Egg and Poultry Production Safety Research Unit

Title: Survival of Antimicrobial Resistant Salmonella Heidelberg Inoculated into Microcosms of Fresh Wood Shavings for Broiler Litter

Author
item Oladeinde, Adelumola - Ade
item COOK, KIMBERLY - US Department Of Agriculture (USDA)
item DIARRA, MOUSSA - Agri Food - Canada
item REHMAN, ATTIQ - Agri Food - Canada
item CARRILO, CATHERINE - Canadian Food Inspection Agency
item WOYDA, REED - Colorado State University
item WIERSMA, CRYSTAL - Colorado State University
item ABDO, ZAID - Colorado State University
item JOHNSON, JASMINE - University Of Georgia
item BOSCH, ANNA - University Of Georgia
item Rothrock, Michael

Submitted to: Canadian Journal of Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Salmonella remains the leading cause of food-borne illnesses linked to chicken consumption. To grow billions of broiler chickens every year, poultry farmers use bedding materials such as wood shavings. Chickens depend on the bedding material for several social activities including coprophagy. Therefore, the bedding chickens are raised on can be a major route of exposure to pathogens. In this study, we showed that Salmonella can persist in pine wood shavings for up to 21 days after inoculation and demonstrated that Salmonella strains that were resistant to third generation cephalosporins were likely to be detected for longer periods than antibiotic susceptible strains. Our results will inform farmers on why it is important to ensure that pine wine wood shavings intended to be used as broiler bedding has low water activity (<0.8).

Technical Abstract: Pine wood shavings (PWS) is the most common bedding material used around the world to raise broiler chickens. In this study we applied an in-depth genomic characterization of Salmonella enterica serovar Heidelberg (S. Heidelberg) strains having different antimicrobial resistance profiles inoculated into fresh PWS as litter. The three strains used for inoculating PWS microcosms were previously isolated from broiler feces (SH-AAFC carries mobilizable blaCMY-2), broiler carcass (SH-ARS is pan susceptible) and chicken thigh (SH-FSIS carries mobilize multidrug resistance genes) and differed from one another by 46 - 94 single nucleotide variants. The SH-ARS isolate was pan susceptible to several antibiotics evaluated. We determined the abundance of Salmonella at days 0, 1, 7, 14 and 21 and performed antibiotic susceptibility testing and whole genome sequencing on seventy-seven S. Heidelberg isolates. After 21 days of incubation, Salmonella abundance decreased by 4.4 Log10 CFU/g while the water activity was the only litter physicochemical variable that correlated with Salmonella abundance. Salmonella with high minimum inhibitory concentrations (MICs) values of ampicillin (= 8 µg/ml) survived longer in PWS compared to Salmonella with high MIC values of gentamicin (= 8 µg/ml). Clonal SH-AAFC was the most prevalent strain in the microcosms (62.3%), followed by the strain SH-ARS (32.4%). Only 4/77 (5.2%) isolates were clones of SH-FSIS. We identified genotype changes that were correlated with S. Heidelberg strains that persisted longer in PWS. Together, these results suggests that genetic determinants of Salmonella play an integral role in the persistence of antimicrobial resistant strains even in absence of environmental selection for resistance.