Influence of infection route and virulence factors on colonization of solid tumors by Salmonella enterica serovar Typhimurium

Administration of facultative anaerobic bacteria like Salmonella enterica serovar Typhimurium (S. typhimurium) as anti-cancer treatment holds a great therapeutic potential. Here we tested different routes of application of S. typhimurium with regard to tumor colonization and therapeutic efficacy. No differences between iv and ip infection were observed, often leading to a complete tumor clearance. In contrast, after oral application tumor colonization was inefficient and delayed. No therapeutic effect was observed under such conditions. We also could show that tumor invasion and colonization was independent of functional SPI 1 and SPI 2. Furthermore, tumor invasion and colonization did not require bacterial motility nor chemotactic responsiveness. The distribution of the bacteria within the tumor was independent of such functions.