Salmonellosis remains a major health problem as Salmonella spp. develop antibiotic resistance. Enteric fever affects approximately 16 million people annually, causing over 600,000 deaths worldwide. Multi-drug resistance (MDR) rates are up to 70% in Asia. Effective antimicrobial therapy is critical. PhoP/Q two-component regulatory system controls the expression of over 40 genes in Salmonella pathogenesis. PhoP DNA binding proteins have positively charged amino acids in the binding site. Preventing PhoP binding may inhibit virulence. Studying PhoP protein and its mutations could help control MDR Salmonella. © 2020 Elsevier B.V., All rights reserved.