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Distinct but Spatially Overlapping Intestinal Niches for Vancomycin-Resistant Enterococcus faecium and Carbapenem-Resistant Klebsiella pneumoniae.

Caballero S, Carter R, Ke X, Sušac B, Leiner IM, Kim GJ, Miller L, Ling L, Manova K, Pamer EG - PLoS Pathog. (2015)

Bottom Line: Herein, we demonstrate that dense intestinal colonization with vancomycin-resistant Enterococcus faecium (VRE) does not reduce in vivo growth of carbapenem-resistant Klebsiella pneumoniae.Reciprocally, K. pneumoniae does not impair intestinal colonization by VRE.While VRE and K. pneumoniae occupy the same three-dimensional space within the gut lumen, their independent growth and persistence in the gut suggests that they reside in distinct niches that satisfy their specific in vivo metabolic needs.

View Article: PubMed Central - PubMed

Affiliation: Immunology Program and Infectious Disease Service, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, New York, United States of America.

ABSTRACT
Antibiotic resistance among enterococci and γ-proteobacteria is an increasing problem in healthcare settings. Dense colonization of the gut by antibiotic-resistant bacteria facilitates their spread between patients and also leads to bloodstream and other systemic infections. Antibiotic-mediated destruction of the intestinal microbiota and consequent loss of colonization resistance are critical factors leading to persistence and spread of antibiotic-resistant bacteria. The mechanisms underlying microbiota-mediated colonization resistance remain incompletely defined and are likely distinct for different antibiotic-resistant bacterial species. It is unclear whether enterococci or γ-proteobacteria, upon expanding to high density in the gut, confer colonization resistance against competing bacterial species. Herein, we demonstrate that dense intestinal colonization with vancomycin-resistant Enterococcus faecium (VRE) does not reduce in vivo growth of carbapenem-resistant Klebsiella pneumoniae. Reciprocally, K. pneumoniae does not impair intestinal colonization by VRE. In contrast, transplantation of a diverse fecal microbiota eliminates both VRE and K. pneumoniae from the gut. Fluorescence in situ hybridization demonstrates that VRE and K. pneumoniae localize to the same regions in the colon but differ with respect to stimulation and invasion of the colonic mucus layer. While VRE and K. pneumoniae occupy the same three-dimensional space within the gut lumen, their independent growth and persistence in the gut suggests that they reside in distinct niches that satisfy their specific in vivo metabolic needs.

No MeSH data available.


Related in: MedlinePlus

K. pneumoniae and VRE occupy a fraction of the total available space in the colon.(A-E) Visualization of bacterial localization by FISH. Entire colon cross-sections from untreated mice (A) and mice treated with ampicillin for 3 weeks (B) were stained with a universal probe that targets the 16S rRNA gene of all bacteria. Cross-sections from ampicillin-treated mice colonized with K. pneumoniae (C) or VRE (D) for 21 days were hybridized with probes specific for K. pneumoniae (Kpn) and Enterococcus, respectively. Sections were counterstained with Hoechst dye to visualize nuclei. Images are representative of 5 mice per group. Scale bar, 500 μm. (E) Number of bacteria per unit area of whole colon cross-sections. n = 3 per group. ND = non-detectable. Error bars (mean ± SEM). **P<0.005, ***P<0.0005 by the Mann-Whitney test.
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ppat.1005132.g005: K. pneumoniae and VRE occupy a fraction of the total available space in the colon.(A-E) Visualization of bacterial localization by FISH. Entire colon cross-sections from untreated mice (A) and mice treated with ampicillin for 3 weeks (B) were stained with a universal probe that targets the 16S rRNA gene of all bacteria. Cross-sections from ampicillin-treated mice colonized with K. pneumoniae (C) or VRE (D) for 21 days were hybridized with probes specific for K. pneumoniae (Kpn) and Enterococcus, respectively. Sections were counterstained with Hoechst dye to visualize nuclei. Images are representative of 5 mice per group. Scale bar, 500 μm. (E) Number of bacteria per unit area of whole colon cross-sections. n = 3 per group. ND = non-detectable. Error bars (mean ± SEM). **P<0.005, ***P<0.0005 by the Mann-Whitney test.

Mentions: The findings that K. pneumoniae and VRE do not interfere with each other’s ability to colonize the gut lumen and that their elimination from the intestine following FMT differs suggest that these bacterial species occupy distinct intestinal niches. To localize bacteria within the colons of mice we performed fluorescence in situ hybridization (FISH) with a universal probe targeting bacterial 16S rRNA genes. In mice that had not been treated with antibiotics, we detected a dense and morphologically diverse bacterial microbiota that was almost completely depleted by ampicillin-treatment (Figs 5A, 5B, S2A and S2B). FISH analysis of antibiotic-treated mice colonized with K. pneumoniae (Kpn), VRE or both with species-specific oligonucleotide probes revealed that K. pneumoniae and VRE were most abundant in luminal areas adjacent to the colonic epithelial layer and that both organisms localized to the same intestinal sites (Figs 5C, 5D and 6A–6D).


Distinct but Spatially Overlapping Intestinal Niches for Vancomycin-Resistant Enterococcus faecium and Carbapenem-Resistant Klebsiella pneumoniae.

Caballero S, Carter R, Ke X, Sušac B, Leiner IM, Kim GJ, Miller L, Ling L, Manova K, Pamer EG - PLoS Pathog. (2015)

K. pneumoniae and VRE occupy a fraction of the total available space in the colon.(A-E) Visualization of bacterial localization by FISH. Entire colon cross-sections from untreated mice (A) and mice treated with ampicillin for 3 weeks (B) were stained with a universal probe that targets the 16S rRNA gene of all bacteria. Cross-sections from ampicillin-treated mice colonized with K. pneumoniae (C) or VRE (D) for 21 days were hybridized with probes specific for K. pneumoniae (Kpn) and Enterococcus, respectively. Sections were counterstained with Hoechst dye to visualize nuclei. Images are representative of 5 mice per group. Scale bar, 500 μm. (E) Number of bacteria per unit area of whole colon cross-sections. n = 3 per group. ND = non-detectable. Error bars (mean ± SEM). **P<0.005, ***P<0.0005 by the Mann-Whitney test.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4559429&req=5

ppat.1005132.g005: K. pneumoniae and VRE occupy a fraction of the total available space in the colon.(A-E) Visualization of bacterial localization by FISH. Entire colon cross-sections from untreated mice (A) and mice treated with ampicillin for 3 weeks (B) were stained with a universal probe that targets the 16S rRNA gene of all bacteria. Cross-sections from ampicillin-treated mice colonized with K. pneumoniae (C) or VRE (D) for 21 days were hybridized with probes specific for K. pneumoniae (Kpn) and Enterococcus, respectively. Sections were counterstained with Hoechst dye to visualize nuclei. Images are representative of 5 mice per group. Scale bar, 500 μm. (E) Number of bacteria per unit area of whole colon cross-sections. n = 3 per group. ND = non-detectable. Error bars (mean ± SEM). **P<0.005, ***P<0.0005 by the Mann-Whitney test.
Mentions: The findings that K. pneumoniae and VRE do not interfere with each other’s ability to colonize the gut lumen and that their elimination from the intestine following FMT differs suggest that these bacterial species occupy distinct intestinal niches. To localize bacteria within the colons of mice we performed fluorescence in situ hybridization (FISH) with a universal probe targeting bacterial 16S rRNA genes. In mice that had not been treated with antibiotics, we detected a dense and morphologically diverse bacterial microbiota that was almost completely depleted by ampicillin-treatment (Figs 5A, 5B, S2A and S2B). FISH analysis of antibiotic-treated mice colonized with K. pneumoniae (Kpn), VRE or both with species-specific oligonucleotide probes revealed that K. pneumoniae and VRE were most abundant in luminal areas adjacent to the colonic epithelial layer and that both organisms localized to the same intestinal sites (Figs 5C, 5D and 6A–6D).

Bottom Line: Herein, we demonstrate that dense intestinal colonization with vancomycin-resistant Enterococcus faecium (VRE) does not reduce in vivo growth of carbapenem-resistant Klebsiella pneumoniae.Reciprocally, K. pneumoniae does not impair intestinal colonization by VRE.While VRE and K. pneumoniae occupy the same three-dimensional space within the gut lumen, their independent growth and persistence in the gut suggests that they reside in distinct niches that satisfy their specific in vivo metabolic needs.

View Article: PubMed Central - PubMed

Affiliation: Immunology Program and Infectious Disease Service, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, New York, United States of America.

ABSTRACT
Antibiotic resistance among enterococci and γ-proteobacteria is an increasing problem in healthcare settings. Dense colonization of the gut by antibiotic-resistant bacteria facilitates their spread between patients and also leads to bloodstream and other systemic infections. Antibiotic-mediated destruction of the intestinal microbiota and consequent loss of colonization resistance are critical factors leading to persistence and spread of antibiotic-resistant bacteria. The mechanisms underlying microbiota-mediated colonization resistance remain incompletely defined and are likely distinct for different antibiotic-resistant bacterial species. It is unclear whether enterococci or γ-proteobacteria, upon expanding to high density in the gut, confer colonization resistance against competing bacterial species. Herein, we demonstrate that dense intestinal colonization with vancomycin-resistant Enterococcus faecium (VRE) does not reduce in vivo growth of carbapenem-resistant Klebsiella pneumoniae. Reciprocally, K. pneumoniae does not impair intestinal colonization by VRE. In contrast, transplantation of a diverse fecal microbiota eliminates both VRE and K. pneumoniae from the gut. Fluorescence in situ hybridization demonstrates that VRE and K. pneumoniae localize to the same regions in the colon but differ with respect to stimulation and invasion of the colonic mucus layer. While VRE and K. pneumoniae occupy the same three-dimensional space within the gut lumen, their independent growth and persistence in the gut suggests that they reside in distinct niches that satisfy their specific in vivo metabolic needs.

No MeSH data available.


Related in: MedlinePlus