Growth enhancement of Salmonella by tungstate treatment

Authors: Anderson, Robin; DOMINGUEZ, DELILA - Texas State University; SHAW, MEGAN - St Edward'S University; Johnson, Casey; AMAT, SAMAT - North Dakota State University; Kotzur, Jacquline; DREWERY, MERRITT - Texas State University; BAYNHAM, PATRICIA - St Edward'S University; Genovese, Kenneth; Crippen, Tawni; Arsenault, Ryan

Submitted to: Pathogens
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/27/2026
Publication Date: 4/29/2026
Citation: Robin C. Anderson, Delila D. Dominguez, Megan R. Shaw, Casey N. Johnson, Samat Amat, Jackie M. Kotzur, Merritt L. Drewery, Patricia J. Baynham, Ken J. Genovese, Tawni L. Crippen, Ryan J. Arsenault. 2026. Growth enhancement of Salmonella by tungstate treatment. Pathogens. 15(5): Article 478. https://doi.org/10.3390/pathogens15050478.
DOI: https://doi.org/10.3390/pathogens15050478

Interpretive Summary: Salmonella are foodborne pathogens that can colonize within the gut of food-producing animals such as cattle, swine, and poultry. Recent work had suggested that the chemical, tungstate, was inhibitory to some foodborne pathogens such as Escherichia coli by targeting their ability to metabolize nutrients they need for growth. Considering that Salmonella and E. coli possess many similar mechanisms to metabolize nutrients, the present study was conducted to see if tungstate may inhibit Salmonella like it does E. coli. Results showed that tungstate did inhibit the ability of Salmonella to metabolize a key nutrient needed for growth but unlike that observed with E. coli, tungstrate treatment enhanced the growth of Salmonella by 100-fold or more when grown in the laboratory. These results suggest that at concentrations and conditions used in this study, tungstate treatment was not an effective treatment to control Salmonella. These results will ultimately help farmers and ranchers understand which treatments will be most effective in controling Salmonella infections in their food production systems.

Technical Abstract: Within the animal gut, Salmonella have traditionally been thought to conserve energy for growth primarily via fermentation but recent reports now indicate ingested Salmonella can orchestrate an increase in host-induced nitrate accumulations within the gut mucosal microenvironment which subsequently favors Salmonella growth via nitrate respiration. Sodium tungstate treatment has been reported to be an effective treatment to inhibit the growth of certain nitrate-respiring Escherichia coli, Paracoccus and Proteus when cultured in gut simulating conditions or within the gut of experimentally treated mice. Mechanistically, tungstate is thought to inhibit growth of nitrate-respiring bacteria by inhibiting molybdenum-containing enzymes critical to nitrate metabolism. Contrary to earlier reports, results from the present study show that 50 to 100 mM sodium tungstate treatment, whether alone or in combination with 5 mM nitrate, markedly increased the amount of growth of Salmonella serovars Newport, Dublin and Typhimurium when grown in pure culture. Moreover, increased growth of experimentally inoculated S. Newport as well as wildtype populations of E. coli and lactic acid bacteria was also observed during in vitro incubation of mixed populations of freshly collected ruminal microbes treated with 100 mM tungstate when compared to non-tungstate treated controls. Effects of tungstate treatment on nitrate and nitrite metabolism were as expected, however, during pure and mixed culture. When cultured with reduced tungsten rather than tungstate, the latter being bound to 4 oxygen atoms, an inhibitory effect on S. Newport was observed and effects on nitrate and nitrite metabolism were consistent with those observed with tungstate. These results suggest that at concentrations and conditions used here, 50 to 100 mM tungstate treatment may have served as a source of oxygen able to support for respiration above that achieved with nitrate alone. This hypothesis, which has yet to be proven, is supported by a marked adverse effect of tungstate, whether alone or in combination with 5 to 6 mM nitrate, on methane and volatile fatty acid production by the mixed population of rumen microbes when compared to untreated or nitrate-only treated populations.