Abstract:
Salmonella, the causative agent of several diseases in humans and animals, including
salmonellosis, septicemia, typhoid fever, and fowl typhoid, poses a serious threat to global public
health and food safety. Globally, reports of therapeutic failures are increasing because of the increase
in bacterial antibiotic resistance. Thus, this work highlights the combined phage–antibiotic therapy
as a promising approach to combating bacterial resistance. In this manner, the phage ZCSE9 was
isolated, and the morphology, host infectivity, killing curve, combination with kanamycin, and
genome analysis of this phage were all examined. Morphologically, phage ZCSE9 is a siphovirus
with a relatively broad host range. In addition, the phage can tolerate high temperatures until 80 ◦C
with one log reduction and a basic environment (pH 11) without a significant decline. Furthermore,
the phage prevents bacterial growth in the planktonic state, according to the results of the time-
killing curve. Moreover, using the phage at MOI 0.1 with kanamycin against five different Salmonella
serotypes reduces the required antibiotics to inhibit the growth of the bacteria. Comparative genomics
and phylogenetic analysis suggested that phage ZCSE9, along with its close relatives Salmonella
phages vB_SenS_AG11 and wksl3, belongs to the genus Jerseyvirus. In conclusion, phage ZCSE9 and
kanamycin form a robust heterologous antibacterial combination that enhances the effectiveness of a
phage-only approach for combating Salmonella.
