Gili Aviv1,2,3, Antje Cornelius4, Maya Davidovich5, Helit Cohen1, Abdulhadi Suwandi6, Alibek Galeev6, Natalie Steck4, Shalhevet Azriel1, Assaf Rokney5, Lea Valinsky5, Galia Rahav1,3, Guntram A Grassl4,6, Ohad Gal-Mor1,2,3. 1. The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer. 2. Department of Clinical Microbiology and Immunology, Jerusalem, Israel. 3. Sackler Faculty of Medicine, Tel Aviv University, Jerusalem, Israel. 4. Research Center Borstel, Germany. 5. Central Laboratories, Ministry of Health, Jerusalem, Israel. 6. Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School and German Center for Infection Research, Partner Site Hannover-Braunschweig.
Abstract
BACKGROUND: Salmonella enterica serovar Infantis (S. Infantis) is one of the ubiquitous serovars of the bacterial pathogen S. enterica and recently has been emerging in many countries worldwide. Nonetheless, not much is known about its epidemiology, host adaptation, and virulence. METHODS: Epidemiological and molecular approaches were used together with tissue-culture and mouse models to conduct phenotypic comparison with the model S. enterica serovar Typhimurium. RESULTS: We show that S. Infantis is more frequently associated with infections in infants <2 years old and prone to cause significantly less invasive infections than serovar Typhimurium. Moreover, although S. Infantis adheres better to host cells and highly colonizes mouse intestines soon after infection, it is significantly less invasive and induces much lower inflammation and disease in vivo than S. Typhimurium. These differences were associated with lower expression of Salmonella pathogenicity island (SPI) 1 genes in S. Infantis than in S. Typhimurium. CONCLUSIONS: Our results demonstrate previously unknown differences in the epidemiology, virulence pathway expression, and pathogenicity between two highly abundant Salmonella serovars and suggest that native variation in the expression of the SPI-1 regulon is likely to contribute to epidemiological and virulence variation between genetically similar nontyphoidal Salmonella serovars.
BACKGROUND:Salmonella enterica serovar Infantis (S. Infantis) is one of the ubiquitous serovars of the bacterial pathogen S. enterica and recently has been emerging in many countries worldwide. Nonetheless, not much is known about its epidemiology, host adaptation, and virulence. METHODS: Epidemiological and molecular approaches were used together with tissue-culture and mouse models to conduct phenotypic comparison with the model S. enterica serovar Typhimurium. RESULTS: We show that S. Infantis is more frequently associated with infections in infants <2 years old and prone to cause significantly less invasive infections than serovar Typhimurium. Moreover, although S. Infantis adheres better to host cells and highly colonizes mouse intestines soon after infection, it is significantly less invasive and induces much lower inflammation and disease in vivo than S. Typhimurium. These differences were associated with lower expression of Salmonella pathogenicity island (SPI) 1 genes in S. Infantis than in S. Typhimurium. CONCLUSIONS: Our results demonstrate previously unknown differences in the epidemiology, virulence pathway expression, and pathogenicity between two highly abundant Salmonella serovars and suggest that native variation in the expression of the SPI-1 regulon is likely to contribute to epidemiological and virulence variation between genetically similar nontyphoidal Salmonella serovars.