Colon cancer and cell transformation by clinical Salmonella strains are associated with bacterial virulence and intracellular fitness

Non-typhoidal Salmonella (NTS) are facultative intracellular pathogens that are associated epidemiologically and experimentally with colon cancer development. Yet, the driving factors of Salmonella -induced cell transformation are mostly unknown. We compared 30 (case) NTS clinical strains isolated from patients who were diagnosed with colon cancer >1 year after NTS infection, versus 30 (control) strains from patients who did not develop colon cancer. While we observed diverse cell invasion and transformation efficiencies among the 60 NTS strains, case strains showed higher transformation efficiency than matching control strains. Genomic and transcriptomic analyses showed that transformation efficiency could not be attributed to specific genomic features, but was associated with gene expression, particularly metabolic genes and regulons. Moreover, high-transforming NTS strains display increased capacity to utilize various nutrient sources, including carbohydrates and amino acids, and grow significantly faster intracellularly than low-transforming NTS. Our results link NTS intracellular virulence to cancer promotion. ![Figure][1] In brief Non-typhoidal Salmonella (NTS) infections can promote cell transformation and colon cancer progression. Yet, little is known about the driving factors of Salmonella -induced transformation. Stévenin et al. performed a multi-omic characterization of clinical NTS strains identified in a nation-wide epidemiological study as associated with colon cancer and revealed a link between bacterial virulence, intracellular fitness, and host cell transformation. Highlights ### Competing Interest Statement The authors have declared no competing interest. [1]: pending:yes