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Lethal inflammasome activation by a multidrug-resistant pathobiont upon antibiotic disruption of the microbiota.

Ayres JS, Trinidad NJ, Vance RE - Nat. Med. (2012)

Bottom Line: The mammalian intestine harbors a complex microbial community that provides numerous benefits to its host.In accordance with Koch's postulates, we found the E. coli pathobiont was sufficient to activate Naip5-Nlrc4 and cause disease when injected intravenously into unmanipulated mice.These findings reveal how sepsis-like disease can result from recognition of pathobionts by the innate immune system.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular & Cell Biology, Division of Immunology & Pathogenesis, University of California, Berkeley, USA. jayres@berkeley.edu

ABSTRACT
The mammalian intestine harbors a complex microbial community that provides numerous benefits to its host. However, the microbiota can also include potentially virulent species, termed pathobiont, which can cause disease when intestinal homeostasis is disrupted. The molecular mechanisms by which pathobionts cause disease remain poorly understood. Here we describe a sepsis-like disease that occurs upon gut injury in antibiotic-treated mice. Sepsis was associated with the systemic spread of a specific multidrug-resistant Escherichia coli pathobiont that expanded markedly in the microbiota of antibiotic-treated mice. Rapid sepsis-like death required a component of the innate immune system, the Naip5-Nlrc4 inflammasome. In accordance with Koch's postulates, we found the E. coli pathobiont was sufficient to activate Naip5-Nlrc4 and cause disease when injected intravenously into unmanipulated mice. These findings reveal how sepsis-like disease can result from recognition of pathobionts by the innate immune system.

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Antibiotic-treatment plus intestinal injury triggers a sepsis-like syndrome in wild-type mice(a) Survival of wild-type male and female mice that received AVNM+5% DSS (n = 5) and 5% DSS-only (n = 8). P = 0.0005 by Log rank analysis.(b) Survival of wild-type male and female mice that received streptomycin+5% DSS (n = 6) and 5% DSS-only (n = 7). P = 0.2818 by Log rank analysis.(c) Weight loss of wild-type male and female mice treated with 5% DSS compared to littermates that received drinking water supplemented with AVNM+5% DSS. Error bars indicate standard deviation; DSS-only (n = 9); AVNM+DSS (n = 9).(d) Length of colons from wild-type male and female mice treated with 5% DSS compared to littermates that received drinking water supplemented with AVNM+5% DSS. Error bars indicate standard deviation. ***P = 0.0003 by Student's t-test. DSS-only (n = 4); AVNM+DSS (n = 4).(e) Representative cecums and colons at 4 d post DSS treatment initiation of wild-type male mice treated with 5% DSS, AVNM+5% DSS or water-treated (unmolested) control littermates.(f) Representative images of small intestine at 4 d post DSS treatment initiation of wild-type male mice treated with 5% DSS, AVNM+5% DSS or water-treated (unmolested) control littermates.(g) Rectal temperature of wild-type male and female mice treated with AVNM+DSS compared to littermates that received 5% DSS only. Error bars represent standard deviation. *P < 0.05 by Student's t-test. DSS-only (n = 8); AVNM/DSS (n = 5).(h) Serum levels of blood urea nitrogen (BUN), creatine phosphokinase (CPK), alanine transaminase and aspartate transaminase (AST) at 3 d post DSS treatment initiation of wild-type male and female mice. Data are representative of two combined experiments. **P < 0.01 and *P < 0.05 by Mann Whitney test. DSS-only (n = 7); AVNM/DSS (n = 7).(i) Levels of culturable bacteria in the lung and liver of wild-type male and female mice 3 d post DSS treatment initiation. Data are representative of three independent experiments. *P < 0.05 by Student's t-test and (n = 4) for both conditions. Red dashed lines indicates limit of detection and black circles indicate individual mice below the limit of detection.
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Figure 1: Antibiotic-treatment plus intestinal injury triggers a sepsis-like syndrome in wild-type mice(a) Survival of wild-type male and female mice that received AVNM+5% DSS (n = 5) and 5% DSS-only (n = 8). P = 0.0005 by Log rank analysis.(b) Survival of wild-type male and female mice that received streptomycin+5% DSS (n = 6) and 5% DSS-only (n = 7). P = 0.2818 by Log rank analysis.(c) Weight loss of wild-type male and female mice treated with 5% DSS compared to littermates that received drinking water supplemented with AVNM+5% DSS. Error bars indicate standard deviation; DSS-only (n = 9); AVNM+DSS (n = 9).(d) Length of colons from wild-type male and female mice treated with 5% DSS compared to littermates that received drinking water supplemented with AVNM+5% DSS. Error bars indicate standard deviation. ***P = 0.0003 by Student's t-test. DSS-only (n = 4); AVNM+DSS (n = 4).(e) Representative cecums and colons at 4 d post DSS treatment initiation of wild-type male mice treated with 5% DSS, AVNM+5% DSS or water-treated (unmolested) control littermates.(f) Representative images of small intestine at 4 d post DSS treatment initiation of wild-type male mice treated with 5% DSS, AVNM+5% DSS or water-treated (unmolested) control littermates.(g) Rectal temperature of wild-type male and female mice treated with AVNM+DSS compared to littermates that received 5% DSS only. Error bars represent standard deviation. *P < 0.05 by Student's t-test. DSS-only (n = 8); AVNM/DSS (n = 5).(h) Serum levels of blood urea nitrogen (BUN), creatine phosphokinase (CPK), alanine transaminase and aspartate transaminase (AST) at 3 d post DSS treatment initiation of wild-type male and female mice. Data are representative of two combined experiments. **P < 0.01 and *P < 0.05 by Mann Whitney test. DSS-only (n = 7); AVNM/DSS (n = 7).(i) Levels of culturable bacteria in the lung and liver of wild-type male and female mice 3 d post DSS treatment initiation. Data are representative of three independent experiments. *P < 0.05 by Student's t-test and (n = 4) for both conditions. Red dashed lines indicates limit of detection and black circles indicate individual mice below the limit of detection.

Mentions: To study the innate immune response to a disrupted intestinal microbiota, we established a disease model that couples antibiotic treatment with the dextran sulfate sodium (DSS)-induced intestinal injury. DSS is toxic to colonic epithelial cells, and typically results in a colitis-like disease23 characterized by severe weight loss, colonic bleeding and colonic shortening (Supplementary Fig 1a, b) . We wanted to understand how antibiotic-induced disruption of the microbiota (dysbiosis) would influence DSS-induced disease. Oral administration of a broad-spectrum antibiotic cocktail composed of ampicillin, vancomycin, neomycin and metronidazole (`AVNM') to colony-born C57BL/6 wild-type mice resulted in a change in the microbiota composition and reduction in the amount of 16S rDNA gene copy number along the intestinal-tract (Supplementary Fig. 1c – e). After this initial treatment, mice were given AVNM+5% DSS and we monitored survival. Consistent with previous reports24, AVNM-treatment rendered wild-type mice more susceptible to DSS (Fig. 1a and Supplementary Fig. 1f). Interestingly, ampicillin alone was sufficient to increase susceptibility to DSS treatment (Supplementary Fig. 1g, h). By contrast, mice treated with the broad-spectrum antibiotic streptomycin were just as susceptible to DSS as non-antibiotic treated mice (Fig. 1b).


Lethal inflammasome activation by a multidrug-resistant pathobiont upon antibiotic disruption of the microbiota.

Ayres JS, Trinidad NJ, Vance RE - Nat. Med. (2012)

Antibiotic-treatment plus intestinal injury triggers a sepsis-like syndrome in wild-type mice(a) Survival of wild-type male and female mice that received AVNM+5% DSS (n = 5) and 5% DSS-only (n = 8). P = 0.0005 by Log rank analysis.(b) Survival of wild-type male and female mice that received streptomycin+5% DSS (n = 6) and 5% DSS-only (n = 7). P = 0.2818 by Log rank analysis.(c) Weight loss of wild-type male and female mice treated with 5% DSS compared to littermates that received drinking water supplemented with AVNM+5% DSS. Error bars indicate standard deviation; DSS-only (n = 9); AVNM+DSS (n = 9).(d) Length of colons from wild-type male and female mice treated with 5% DSS compared to littermates that received drinking water supplemented with AVNM+5% DSS. Error bars indicate standard deviation. ***P = 0.0003 by Student's t-test. DSS-only (n = 4); AVNM+DSS (n = 4).(e) Representative cecums and colons at 4 d post DSS treatment initiation of wild-type male mice treated with 5% DSS, AVNM+5% DSS or water-treated (unmolested) control littermates.(f) Representative images of small intestine at 4 d post DSS treatment initiation of wild-type male mice treated with 5% DSS, AVNM+5% DSS or water-treated (unmolested) control littermates.(g) Rectal temperature of wild-type male and female mice treated with AVNM+DSS compared to littermates that received 5% DSS only. Error bars represent standard deviation. *P < 0.05 by Student's t-test. DSS-only (n = 8); AVNM/DSS (n = 5).(h) Serum levels of blood urea nitrogen (BUN), creatine phosphokinase (CPK), alanine transaminase and aspartate transaminase (AST) at 3 d post DSS treatment initiation of wild-type male and female mice. Data are representative of two combined experiments. **P < 0.01 and *P < 0.05 by Mann Whitney test. DSS-only (n = 7); AVNM/DSS (n = 7).(i) Levels of culturable bacteria in the lung and liver of wild-type male and female mice 3 d post DSS treatment initiation. Data are representative of three independent experiments. *P < 0.05 by Student's t-test and (n = 4) for both conditions. Red dashed lines indicates limit of detection and black circles indicate individual mice below the limit of detection.
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Figure 1: Antibiotic-treatment plus intestinal injury triggers a sepsis-like syndrome in wild-type mice(a) Survival of wild-type male and female mice that received AVNM+5% DSS (n = 5) and 5% DSS-only (n = 8). P = 0.0005 by Log rank analysis.(b) Survival of wild-type male and female mice that received streptomycin+5% DSS (n = 6) and 5% DSS-only (n = 7). P = 0.2818 by Log rank analysis.(c) Weight loss of wild-type male and female mice treated with 5% DSS compared to littermates that received drinking water supplemented with AVNM+5% DSS. Error bars indicate standard deviation; DSS-only (n = 9); AVNM+DSS (n = 9).(d) Length of colons from wild-type male and female mice treated with 5% DSS compared to littermates that received drinking water supplemented with AVNM+5% DSS. Error bars indicate standard deviation. ***P = 0.0003 by Student's t-test. DSS-only (n = 4); AVNM+DSS (n = 4).(e) Representative cecums and colons at 4 d post DSS treatment initiation of wild-type male mice treated with 5% DSS, AVNM+5% DSS or water-treated (unmolested) control littermates.(f) Representative images of small intestine at 4 d post DSS treatment initiation of wild-type male mice treated with 5% DSS, AVNM+5% DSS or water-treated (unmolested) control littermates.(g) Rectal temperature of wild-type male and female mice treated with AVNM+DSS compared to littermates that received 5% DSS only. Error bars represent standard deviation. *P < 0.05 by Student's t-test. DSS-only (n = 8); AVNM/DSS (n = 5).(h) Serum levels of blood urea nitrogen (BUN), creatine phosphokinase (CPK), alanine transaminase and aspartate transaminase (AST) at 3 d post DSS treatment initiation of wild-type male and female mice. Data are representative of two combined experiments. **P < 0.01 and *P < 0.05 by Mann Whitney test. DSS-only (n = 7); AVNM/DSS (n = 7).(i) Levels of culturable bacteria in the lung and liver of wild-type male and female mice 3 d post DSS treatment initiation. Data are representative of three independent experiments. *P < 0.05 by Student's t-test and (n = 4) for both conditions. Red dashed lines indicates limit of detection and black circles indicate individual mice below the limit of detection.
Mentions: To study the innate immune response to a disrupted intestinal microbiota, we established a disease model that couples antibiotic treatment with the dextran sulfate sodium (DSS)-induced intestinal injury. DSS is toxic to colonic epithelial cells, and typically results in a colitis-like disease23 characterized by severe weight loss, colonic bleeding and colonic shortening (Supplementary Fig 1a, b) . We wanted to understand how antibiotic-induced disruption of the microbiota (dysbiosis) would influence DSS-induced disease. Oral administration of a broad-spectrum antibiotic cocktail composed of ampicillin, vancomycin, neomycin and metronidazole (`AVNM') to colony-born C57BL/6 wild-type mice resulted in a change in the microbiota composition and reduction in the amount of 16S rDNA gene copy number along the intestinal-tract (Supplementary Fig. 1c – e). After this initial treatment, mice were given AVNM+5% DSS and we monitored survival. Consistent with previous reports24, AVNM-treatment rendered wild-type mice more susceptible to DSS (Fig. 1a and Supplementary Fig. 1f). Interestingly, ampicillin alone was sufficient to increase susceptibility to DSS treatment (Supplementary Fig. 1g, h). By contrast, mice treated with the broad-spectrum antibiotic streptomycin were just as susceptible to DSS as non-antibiotic treated mice (Fig. 1b).

Bottom Line: The mammalian intestine harbors a complex microbial community that provides numerous benefits to its host.In accordance with Koch's postulates, we found the E. coli pathobiont was sufficient to activate Naip5-Nlrc4 and cause disease when injected intravenously into unmanipulated mice.These findings reveal how sepsis-like disease can result from recognition of pathobionts by the innate immune system.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular & Cell Biology, Division of Immunology & Pathogenesis, University of California, Berkeley, USA. jayres@berkeley.edu

ABSTRACT
The mammalian intestine harbors a complex microbial community that provides numerous benefits to its host. However, the microbiota can also include potentially virulent species, termed pathobiont, which can cause disease when intestinal homeostasis is disrupted. The molecular mechanisms by which pathobionts cause disease remain poorly understood. Here we describe a sepsis-like disease that occurs upon gut injury in antibiotic-treated mice. Sepsis was associated with the systemic spread of a specific multidrug-resistant Escherichia coli pathobiont that expanded markedly in the microbiota of antibiotic-treated mice. Rapid sepsis-like death required a component of the innate immune system, the Naip5-Nlrc4 inflammasome. In accordance with Koch's postulates, we found the E. coli pathobiont was sufficient to activate Naip5-Nlrc4 and cause disease when injected intravenously into unmanipulated mice. These findings reveal how sepsis-like disease can result from recognition of pathobionts by the innate immune system.

Show MeSH
Related in: MedlinePlus