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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Poultry Microbiological Safety and Processing Research Unit » Research » Publications at this Location » Publication #425653
Research Project: Alternatives to Antibiotics and Genomics of Antimicrobial Resistance to Control Foodborne Pathogens in Poultry

Location: Poultry Microbiological Safety and Processing Research Unit

Title: Detection of a hydrogen sulfide-negative Salmonella Typhimurium from cattle feces in a cross-sectional study of cow–calf herds in the Southeastern United States

Author
item BENTUM, KINGSLEY - Tuskegee University
item KUUFIRE, EMMANUEL - Tuskegee University
item NYARKU, REJOICE - Tuskegee University
item WOODS, CHASE - Tuskegee University
item ALE, KHIM - Tuskegee University
item MCKIE, LUIS - Tuskegee University
item MCKENZIE, DAVID - Tuskegee University
item SAMUEL, TEMESGEN - Tuskegee University
item Jackson, Charlene
item ADEISYUN, ABIODUN - University Of The West Indies
item ABEBE, WOUBIT - Tuskegee University

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2025
Publication Date: 7/29/2025
Citation: Bentum, K., Kuufire, E., Nyarku, R., Woods, C., Ale, K., Mckie, L., Mckenzie, D., Samuel, T., Jackson, C.R., Adeisyun, A., Abebe, W. 2025. Detection of a hydrogen sulfide-negative Salmonella Typhimurium from cattle feces in a cross-sectional study of cow–calf herds in the Southeastern United States. Frontiers in Veterinary Science. 12(1619880). https://doi.org/10.3389/fvets.2025.1619880.
DOI: https://doi.org/10.3389/fvets.2025.1619880

Interpretive Summary: Although cattle are notable reservoirs of Salmonella, few studies have reported the isolation of the emerging atypical hydrogen sulfide-negative strain of the pathogen from bovine sources. These atypical strains can cause disease outbreaks yet easily elude detection. This study investigated the antimicrobial resistance profiles and epidemiology of Salmonella among cow-calf herds in Alabama, U.S., while attempting to isolate its emerging hydrogen sulfide-negative variant. From 18 farm operations, 311 fecal samples from cattle were cultured for Salmonella. In summary, 3.5% (11/311) of the animals sampled from 27.8% (5/18) of the farms tested positive for Salmonella. Fifteen isolates from six Salmonella serovars were identified including Thompson, Hadar, Braenderup, Enteritidis, Bareilly, and Typhimurium. Of these, only the S. Hadar isolates were resistant to tetracycline due to the tet(A) gene. The S. Typhimurium isolate was identified as a hydrogen sulfide-negative serovar with mutations in two genes for reducing thiosulfate to hydrogen sulfide. This study is important for food safety and diagnostic laboratories as it shows the presence of hydrogen sulfide-negative Salmonella among food animals and the need for alternative isolation protocols to detect these strains.

Technical Abstract: Cross-sectional surveys are important in identifying emerging and re-emerging pathogens. Although cattle are notable reservoirs of Salmonella, few studies have reported the isolation of the emerging atypical H2S-negative strain of the pathogen from bovine sources. These atypical strains can cause disease outbreaks yet easily elude detection. This study investigates the antimicrobial resistance profiles and epidemiology of Salmonella among cow-calf herds in Alabama, U.S., while attempting to isolate its emerging H2S-negative variant. From 18 farm operations, 311 fecal samples from cattle were cultured for Salmonella, and all isolates recovered were identified using the Salmonella In Silico Typing Resource after whole genome sequencing. Xylose Lysine Deoxycholate agar, Lysine Iron Agar, and Triple Sugar Iron agar were used to confirm H2S production by the isolates, and their antimicrobial susceptibilities were tested against 24 antimicrobial agents. In summary, 3.5% (11/311) of the animals sampled from 27.8% (5/18) of the farms tested positive for Salmonella. Fifteen isolates from six serovars were identified: Salmonella Thompson (5/15), Salmonella Hadar (4/15), Salmonella Braenderup (3/15), Salmonella Enteritidis (1/15), Salmonella Bareilly (1/15), and Salmonella Typhimurium (1/15). Of these, only the Salmonella Hadar isolates were completely resistant. The resistance was against tetracycline, as all four isolates had the tet(A) gene. The Salmonella Typhimurium isolate was identified as an H2S-negative serovar with an A>C missense mutation and a C>T synonymous mutation on the phsC and cysI genes, respectively. This study shows the continuous circulation of H2S-negative Salmonella among food animals and the need to be intentional about their isolation in routine Salmonella detection.