Study of a lytic bacteriophage as a tool for the control of Salmonella Gallinarum in layer poultry

Abstract

One of the leading diseases affecting laying poultry in Argentina is fowl typhoid, caused by the pathogenSalmonella entericaserovar Gallinarum (S.Gallinarum). Although this disease was eradicated fromindustrial hatcheries in several developed countries, it is still present in commercial farms in LatinAmerica, causing substantial economic losses due to high mortality rates, limited production of qualityeggs, high veterinary costs, and the need to renovate infected facilities. To develop a newS.Gallinarumbiocontrol method, in the present study, we characterized a bacteriophage in terms of host specificity,growth kinetics, and stability under different environmental conditions. The phage could infect anample range of bacterial hosts and had no lytic activity against the vaccine strain 9R. Moreover, thephage was stable at pH 3, chloroform presence did not significantly reduce its titer, and its activity wasnot affected by antibiotics or various chemical agents often used in aviculture. Application of a phagesuspension onS.Gallinarum-contaminated surfaces resulted in a significant reduction of bacterial load(p < 0.05). These results show that lytic bacteriophages such as the one studied here are innovativealternatives with potential applications to controlS.Gallinarum in laying poultry farms.

Keywords

• bacteriophage;salmonellagallinarum; fowl typhoid; laying poultry; biocontrol.