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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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Expansion and extraintestinal colonization of a multi-drug resistant E. coli in response to intestinal injury in dysbiotic mice(a) Levels of AVNM-resistant bacteria in the intestinal-tract of AVNM-treated and water-treated wild-type male and female littermates 7 d post treatment-initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions(b) Levels of AVNM-resistant bacteria in the lung of AVNM- plus DSS-treated and DSS-only treated male and female littermates 7 d post DSS treatment initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions. Red dashed line represents the limit of detection and black circles represent individual mice below the limit of detection.(c) Levels of AVNM-resistant bacteria in the liver of AVNM- plus DSS-treated and DSS-only treated male and female littermates 7 d post DSS treatment initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions(d) Representative images of disc diffusion assays and quantitation of the zone of inhibition to determine the susceptibility of an E. coli-O21:H+ isolate to AVNM or streptomycin. E. coli-K12 was used as a control. Error bars indicate standard deviation.(e) Intestinal levels of total AVNM-resistant bacteria and AVNM-resistant E. coli-O21:H+ in AVNM-treated wild-type male and female mice compared to littermates that received a water control. DSS-treated mice (n = 4) and AVNM+DSS-treated mice (n = 4). Red dashed line represents the limit of detection and black circles represent individual mice below the limit of detection.(f) Lung and liver levels of total AVNM-resistant bacteria and AVNM-resistant E. coli-O21:H+ in AVNM+DSS-treated wild-type male and female mice compared to littermates that received a DSS-only control. DSS-treated mice (n = 4) and AVNM+DSS-treated mice (n = 4).(g) Intestinal levels of AVNM-resistant E. coli and streptomycin-resistant E. coli in AVNM and streptomycin-treated wild-type male and female mice were determined and compared to wild-type littermates that received a water control. Unmolested mice (n = 4); AVNM treated mice (n = 4) and streptomycin treated mice (n = 4).(h) Intestinal levels of AVNM-resistant E. coli in single-housed female Jax mice and Jax mice co-housed with female colony-born (CB) mice after 7 d of AVNM treatment. Jax single-housed (n = 3); Jax co-housed (n = 3) and CB co-housed (n = 3).(i) Temperature and survival of AVNM+DSS-treated female single-housed Jax mice and Jax mice co-housed with female colony-born mice. For survival, P = 0.0236 by Log rank analysis. Data represent two combined experiments; Jax single-housed (n = 11), Jax co-housed (n = 11); CB co-housed (n = 11) and DSS only (n = 5). Error bars indicate standard deviation.
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Figure 2: Expansion and extraintestinal colonization of a multi-drug resistant E. coli in response to intestinal injury in dysbiotic mice(a) Levels of AVNM-resistant bacteria in the intestinal-tract of AVNM-treated and water-treated wild-type male and female littermates 7 d post treatment-initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions(b) Levels of AVNM-resistant bacteria in the lung of AVNM- plus DSS-treated and DSS-only treated male and female littermates 7 d post DSS treatment initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions. Red dashed line represents the limit of detection and black circles represent individual mice below the limit of detection.(c) Levels of AVNM-resistant bacteria in the liver of AVNM- plus DSS-treated and DSS-only treated male and female littermates 7 d post DSS treatment initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions(d) Representative images of disc diffusion assays and quantitation of the zone of inhibition to determine the susceptibility of an E. coli-O21:H+ isolate to AVNM or streptomycin. E. coli-K12 was used as a control. Error bars indicate standard deviation.(e) Intestinal levels of total AVNM-resistant bacteria and AVNM-resistant E. coli-O21:H+ in AVNM-treated wild-type male and female mice compared to littermates that received a water control. DSS-treated mice (n = 4) and AVNM+DSS-treated mice (n = 4). Red dashed line represents the limit of detection and black circles represent individual mice below the limit of detection.(f) Lung and liver levels of total AVNM-resistant bacteria and AVNM-resistant E. coli-O21:H+ in AVNM+DSS-treated wild-type male and female mice compared to littermates that received a DSS-only control. DSS-treated mice (n = 4) and AVNM+DSS-treated mice (n = 4).(g) Intestinal levels of AVNM-resistant E. coli and streptomycin-resistant E. coli in AVNM and streptomycin-treated wild-type male and female mice were determined and compared to wild-type littermates that received a water control. Unmolested mice (n = 4); AVNM treated mice (n = 4) and streptomycin treated mice (n = 4).(h) Intestinal levels of AVNM-resistant E. coli in single-housed female Jax mice and Jax mice co-housed with female colony-born (CB) mice after 7 d of AVNM treatment. Jax single-housed (n = 3); Jax co-housed (n = 3) and CB co-housed (n = 3).(i) Temperature and survival of AVNM+DSS-treated female single-housed Jax mice and Jax mice co-housed with female colony-born mice. For survival, P = 0.0236 by Log rank analysis. Data represent two combined experiments; Jax single-housed (n = 11), Jax co-housed (n = 11); CB co-housed (n = 11) and DSS only (n = 5). Error bars indicate standard deviation.

Mentions: Several non-exclusive models could explain how alterations in the microbiota can trigger disease. For example, antibiotic treatment could eliminate members of the microbiota that elicit protective host responses24. In addition, antibiotics could result in the overgrowth of AVNM-resistant pathobionts. Consistent with the latter possibility, after 7 d of AVNM-treatment, colony-born wild-type mice harbored an expanded population of AVNM-resistant bacteria along the intestinal-tract (Fig. 2a). We observed a similar expansion of an AVNM-resistant population in Taconic mice, but no detectable levels of culturable AVNM-resistant bacteria in Jax mice (Supplementary Fig. 3). Furthermore, we found that the AVNM-resistant bacteria colonized extraintestinal tissues of AVNM+DSS colony-born wild-type mice (Fig. 2b, c and Supplementary Fig. 2). Thus, sepsis-like disease correlated with the intestinal expansion and extraintestinal colonization of AVNM-resistant bacteria.


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

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

Expansion and extraintestinal colonization of a multi-drug resistant E. coli in response to intestinal injury in dysbiotic mice(a) Levels of AVNM-resistant bacteria in the intestinal-tract of AVNM-treated and water-treated wild-type male and female littermates 7 d post treatment-initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions(b) Levels of AVNM-resistant bacteria in the lung of AVNM- plus DSS-treated and DSS-only treated male and female littermates 7 d post DSS treatment initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions. Red dashed line represents the limit of detection and black circles represent individual mice below the limit of detection.(c) Levels of AVNM-resistant bacteria in the liver of AVNM- plus DSS-treated and DSS-only treated male and female littermates 7 d post DSS treatment initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions(d) Representative images of disc diffusion assays and quantitation of the zone of inhibition to determine the susceptibility of an E. coli-O21:H+ isolate to AVNM or streptomycin. E. coli-K12 was used as a control. Error bars indicate standard deviation.(e) Intestinal levels of total AVNM-resistant bacteria and AVNM-resistant E. coli-O21:H+ in AVNM-treated wild-type male and female mice compared to littermates that received a water control. DSS-treated mice (n = 4) and AVNM+DSS-treated mice (n = 4). Red dashed line represents the limit of detection and black circles represent individual mice below the limit of detection.(f) Lung and liver levels of total AVNM-resistant bacteria and AVNM-resistant E. coli-O21:H+ in AVNM+DSS-treated wild-type male and female mice compared to littermates that received a DSS-only control. DSS-treated mice (n = 4) and AVNM+DSS-treated mice (n = 4).(g) Intestinal levels of AVNM-resistant E. coli and streptomycin-resistant E. coli in AVNM and streptomycin-treated wild-type male and female mice were determined and compared to wild-type littermates that received a water control. Unmolested mice (n = 4); AVNM treated mice (n = 4) and streptomycin treated mice (n = 4).(h) Intestinal levels of AVNM-resistant E. coli in single-housed female Jax mice and Jax mice co-housed with female colony-born (CB) mice after 7 d of AVNM treatment. Jax single-housed (n = 3); Jax co-housed (n = 3) and CB co-housed (n = 3).(i) Temperature and survival of AVNM+DSS-treated female single-housed Jax mice and Jax mice co-housed with female colony-born mice. For survival, P = 0.0236 by Log rank analysis. Data represent two combined experiments; Jax single-housed (n = 11), Jax co-housed (n = 11); CB co-housed (n = 11) and DSS only (n = 5). Error bars indicate standard deviation.
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Figure 2: Expansion and extraintestinal colonization of a multi-drug resistant E. coli in response to intestinal injury in dysbiotic mice(a) Levels of AVNM-resistant bacteria in the intestinal-tract of AVNM-treated and water-treated wild-type male and female littermates 7 d post treatment-initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions(b) Levels of AVNM-resistant bacteria in the lung of AVNM- plus DSS-treated and DSS-only treated male and female littermates 7 d post DSS treatment initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions. Red dashed line represents the limit of detection and black circles represent individual mice below the limit of detection.(c) Levels of AVNM-resistant bacteria in the liver of AVNM- plus DSS-treated and DSS-only treated male and female littermates 7 d post DSS treatment initiation. *P < 0.05 by Student's t-test and (n = 4) for both conditions(d) Representative images of disc diffusion assays and quantitation of the zone of inhibition to determine the susceptibility of an E. coli-O21:H+ isolate to AVNM or streptomycin. E. coli-K12 was used as a control. Error bars indicate standard deviation.(e) Intestinal levels of total AVNM-resistant bacteria and AVNM-resistant E. coli-O21:H+ in AVNM-treated wild-type male and female mice compared to littermates that received a water control. DSS-treated mice (n = 4) and AVNM+DSS-treated mice (n = 4). Red dashed line represents the limit of detection and black circles represent individual mice below the limit of detection.(f) Lung and liver levels of total AVNM-resistant bacteria and AVNM-resistant E. coli-O21:H+ in AVNM+DSS-treated wild-type male and female mice compared to littermates that received a DSS-only control. DSS-treated mice (n = 4) and AVNM+DSS-treated mice (n = 4).(g) Intestinal levels of AVNM-resistant E. coli and streptomycin-resistant E. coli in AVNM and streptomycin-treated wild-type male and female mice were determined and compared to wild-type littermates that received a water control. Unmolested mice (n = 4); AVNM treated mice (n = 4) and streptomycin treated mice (n = 4).(h) Intestinal levels of AVNM-resistant E. coli in single-housed female Jax mice and Jax mice co-housed with female colony-born (CB) mice after 7 d of AVNM treatment. Jax single-housed (n = 3); Jax co-housed (n = 3) and CB co-housed (n = 3).(i) Temperature and survival of AVNM+DSS-treated female single-housed Jax mice and Jax mice co-housed with female colony-born mice. For survival, P = 0.0236 by Log rank analysis. Data represent two combined experiments; Jax single-housed (n = 11), Jax co-housed (n = 11); CB co-housed (n = 11) and DSS only (n = 5). Error bars indicate standard deviation.
Mentions: Several non-exclusive models could explain how alterations in the microbiota can trigger disease. For example, antibiotic treatment could eliminate members of the microbiota that elicit protective host responses24. In addition, antibiotics could result in the overgrowth of AVNM-resistant pathobionts. Consistent with the latter possibility, after 7 d of AVNM-treatment, colony-born wild-type mice harbored an expanded population of AVNM-resistant bacteria along the intestinal-tract (Fig. 2a). We observed a similar expansion of an AVNM-resistant population in Taconic mice, but no detectable levels of culturable AVNM-resistant bacteria in Jax mice (Supplementary Fig. 3). Furthermore, we found that the AVNM-resistant bacteria colonized extraintestinal tissues of AVNM+DSS colony-born wild-type mice (Fig. 2b, c and Supplementary Fig. 2). Thus, sepsis-like disease correlated with the intestinal expansion and extraintestinal colonization of AVNM-resistant bacteria.

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