Effect of streptomycin administration on association of enteric pathogens with cecal tissue of mice

Abstract

The effect of streptomycin on the ability of Shigella sonnei 3SR and enterotoxigenic Escherichia coli 2SR to associate with cecal tissue of mice in vivo and in vitro was examined. After orogastric challenge, both pathogens associated in significantly greater numbers (P < 0.05) with the cecal tissue of streptomycin-treated mice than with the tissue of untreated mice. The population levels of the pathogens were also significantly greater (P < 0.05) in the cecal contents of streptomycin-treated mice than in untreated mice. When excised cecal tissues from the two groups of mice were exposed to the pathogens in vitro, the extent of the association of the pathogens was markedly greater with tissues from streptomycin-treated mice than with tissues from untreated mice. There was also a positive correlation between the numbers of the pathogens in the suspending fluid and the extent of the tissue associations. The population size of fusiform organisms, which are the major components of the mucus layer of the ceca of mice, was reduced 100-fold by streptomycin administration. This was determined by microscopic count. Sections of cecal tissue obtained from the mice and stained with hematoxylin and eosin demonstrated that streptomycin administration greatly decreased the number of fusiform bacteria present in the mucosal microbial layer. We speculate that the partial elimination of fusiform organisms from this layer by streptomycin administration provides available association sites for pathogens so that they can successfully colonize the mouse cecum.

Shigella Diversity and Changing Landscape: Insights for the Twenty-First Century

“…Germ free mice and Guinea pigs monocolonized with E. coli were shown to block the establishment of S. flexneri whereas monocolonization with Bacteroides, Bifidobacterium, or Streptococcus had no effect on Shigella levels (Formal et al, 1961 ; Maier and Hentges, 1972 ). Other studies have shown treatment with streptomycin produces an environment that supports Shigella colonization in mice (Pongpech et al, 1989 ; Martino et al, 2005 ). Together these studies suggest a complex interplay between Shigella and commensal bacteria that are not easily reconciled with the low infectious dose observed in humans.…”

Spatial distribution of Escherichia coli in the mouse large intestine inferred from rRNA in situ hybridization

“…1C, that in the large intestines from the conventional mice fusiform bacteria are in abundance, but they are eliminated when streptomycin is administrated to the mice, as previously described(12,16). It has previously been reported that indigenous microorganisms adhere to the membrane of intestinal epithelial cells viaINFECT.…”

Development of caecaloids to study host–pathogen interactions: new insights into immunoregulatory functions of Trichuris muris extracellular vesicles in the caecum

“…The caecal epithelium is the primary colonisation site and port of entry for many clinically important pathogens for which mouse models exist, including Trichuris trichiura (model organism T. muris), Salmonella enterica, serovar Typhymurium, Campylobacter jejuni, Shigella sonnei, Escherichia coli (ETEC, model organism Citrobacter rodentium ), Yersinia pseudotuberculosis and Entamoeba histolytica, among others ( Lee et al, 1986 , Pongpech et al, 1989 , Houpt et al, 2002 , Barthel et al, 2003 , Klementowicz et al, 2012 , Collins et al, 2014 , Fahlgren et al, 2014 ). Developing mouse caecaloid cultures will enable host interactions of these important pathogens to be studied in an in vitro model.…”