Enteric salmonellosis disrupts the microbial ecology of the murine gastrointestinal tract. Infect Immun 2008 Mar;76(3):907-15
Date
12/28/2007Pubmed ID
18160481Pubmed Central ID
PMC2258829DOI
10.1128/IAI.01432-07Scopus ID
2-s2.0-40749084834 (requires institutional sign-in at Scopus site) 334 CitationsAbstract
The commensal microbiota protects the murine host from enteric pathogens. Nevertheless, specific pathogens are able to colonize the intestinal tract and invade, despite the presence of an intact biota. Possibly, effective pathogens disrupt the indigenous microbiota, either directly through pathogen-commensal interaction, indirectly via the host mucosal immune response to the pathogen, or by a combination of these factors. This study investigates the effect of peroral Salmonella enterica serovar Typhimurium infection on the intestinal microbiota. Since the majority of the intestinal microbiota cannot be cultured by conventional techniques, molecular approaches using 16S rRNA sequences were applied. Several major bacterial groups were assayed using quantitative PCR. Administration of either the 50% lethal dose (LD(50)) or 10x LD(50) of Salmonella enterica serovar Typhimurium caused changes in the microbiota throughout the intestinal tract over the time course of infection. A 95% decrease in total bacterial number was noted in the cecum and large intestine with 10x LD(50) S. enterica serovar Typhimurium challenge at 7 days postinfection, concurrent with gross evidence of diarrhea. In addition, alterations in microbiota composition preceded the onset of diarrhea, suggesting the involvement of pathogen-commensal interactions and/or host responses unrelated to diarrhea. Microbiota alterations were not permanent and reverted to the microbiota of uninfected mice by 1 month postinfection. Infection with a Salmonella pathogenicity island 1 (SPI1) mutant did not result in microbiota alterations, while SPI2 mutant infections triggered partial changes. Neither mutant was capable of prolonged colonization or induction of mucosal inflammation. These data suggest that several Salmonella virulence factors, particularly those involved in the local mucosal host response, are required for disruption of the intestinal ecosystem.
Author List
Barman M, Unold D, Shifley K, Amir E, Hung K, Bos N, Salzman NAuthor
Nita H. Salzman MD, PhD Director, Professor in the Pediatrics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsBacteria
Biodiversity
Colony Count, Microbial
DNA, Bacterial
DNA, Ribosomal
Ecosystem
Female
Gastrointestinal Tract
Genomic Islands
In Situ Hybridization, Fluorescence
Lethal Dose 50
Male
Mice
Mutation
Polymerase Chain Reaction
RNA, Ribosomal, 16S
Salmonella Infections, Animal
Salmonella typhimurium
Sequence Analysis, DNA
Time Factors
