Dataset Information

Pathogen clonal expansion underlies multiorgan dissemination and organ-specific outcomes during murine systemic infection.

ABSTRACT: The dissemination of pathogens through blood and their establishment within organs lead to severe clinical outcomes. However, the within-host dynamics that underlie pathogen spread to and clearance from systemic organs remain largely uncharacterized. In animal models of infection, the observed pathogen population results from the combined contributions of bacterial replication, persistence, death, and dissemination, each of which can vary across organs. Quantifying the contribution of each these processes is required to interpret and understand experimental phenotypes. Here, we leveraged STAMPR, a new barcoding framework, to investigate the population dynamics of extraintestinal pathogenic Escherichia coli, a common cause of bacteremia, during murine systemic infection. We show that while bacteria are largely cleared by most organs, organ-specific clearance failures are pervasive and result from dramatic expansions of clones representing less than 0.0001% of the inoculum. Clonal expansion underlies the variability in bacterial burden between animals, and stochastic dissemination of clones profoundly alters the pathogen population structure within organs. Despite variable pathogen expansion events, host bottlenecks are consistent yet highly sensitive to infection variables, including inoculum size and macrophage depletion. We adapted our barcoding methodology to facilitate multiplexed validation of bacterial fitness determinants identified with transposon mutagenesis and confirmed the importance of bacterial hexose metabolism and cell envelope homeostasis pathways for organ-specific pathogen survival. Collectively, our findings provide a comprehensive map of the population biology that underlies bacterial systemic infection and a framework for barcode-based high-resolution mapping of infection dynamics.

SUBMITTER: Hullahalli K

PROVIDER: S-EPMC8545400 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundThe number of Medicaid beneficiaries has increased under the Affordable Care Act, improving access to solid organ transplantation in this disadvantaged patient cohort. It is unclear what impact Medicaid expansion will have on transplantation outcomes. We performed a retrospective cohort analysis to measure the frequency and variation in Medicaid transplantation and post-transplantation survival in Medicaid patients.Study designAdult heart, lung, liver, and renal transplant recipients between 2002 and 2011 (n = 169,194) reported to the Scientific Registry of Transplant Recipients were identified. Transplant recipients were classified based on insurance status (private, Medicare or Medicaid). Outcomes measures included 5-year post-transplantation survival, summarized using Kaplan-Meier curves and compared with log-rank tests. Organ-specific Cox proportional hazards models were used to adjust for donor and recipient factors.ResultsMedicaid patients comprised 8.6% of all organ transplant recipients. Fewer transplantations were performed than expected among Medicaid beneficiaries for all organs except liver (liver: observed to expected ratio = 1.21; 95% CI, 0.68-1.90; heart: observed to expected ratio = 0.89; 95% CI, 0.44-1.49; lung: observed to expected ratio = 0.57; 95% CI, 0.22-1.06; renal: observed to expected ratio = 0.32; 95% CI, 0.08-0.72). Medicaid transplant recipients were listed with more severe organ failure and experienced shorter transplant wait times. Post-transplantation survival was lower in Medicaid patients compared with private insurance for all organs. Post-transplantation survival in Medicaid patients was similar to Medicare patients for heart, liver, and renal but lower in lung.ConclusionsMedicaid organ transplant beneficiaries had significantly lower survival compared with privately insured beneficiaries. The more severe organ failure among Medicaid beneficiaries at the time of listing, suggested a pattern of late referral, which might account for worse outcomes. Implementation of the Affordable Care Act gives the opportunity to develop the necessary infrastructure to ensure timely transplantation referrals and improve long-term outcomes in this vulnerable population.

Project description:Severe acute pancreatitis (SAP) includes persistent systemic inflammation (SIRS) and multiorgan failure (MOF). The mechanism of transition from SIRS to MOF is unclear. We developed a fluid compartment model and used clinical data to test predictions. The model includes vascular, interstitial and "third-space" compartments with variable permeability of plasma proteins at the capillaries. Consented patients from University of Pittsburgh Medical Center Presbyterian Hospital were studied. Preadmission and daily hematocrit (HCT), blood urea nitrogen (BUN), creatine (Cr), albumin (Alb), and total protein (TP) were collected, and nonalbumin plasma protein (NAPP = TP minus the Alb) was calculated. Subjects served as their own controls for trajectory analysis. Of 57 SAP subjects, 18 developed MOF (5 died), and 39 were non-MOF (0 died). Compared with preadmission levels, admission HCT increased in MOF +5.00 [25%-75% interquartile range, IQR] versus non-MOF -0.10 [-1.55, 1.40] (P < 0.002) with HCT > +3 distinguishing MOF from non-MOF (odds ratio 17.7, P = 0.014). Preadmission Alb fell faster in MOF than non-MOF (P < 0.01). By day 2, TP and NAPP dropped in MOF but not non-MOF (P < 0.001). BUN and Cr levels increased in MOF (P = 0.001), but BUN-to-Cr ratios remained constant. Pancreatic necrosis was more common in MOF (56%) than non-MOF (23%). Changing capillary permeability to allow loss of NAPP in this model predicts loss of plasma oncotic pressure and reduced vascular volume, hypotension with prerenal azotemia and acute kidney dysfunction, pancreas necrosis, and pulmonary edema from capillary leak in the lung with acute respiratory distress syndrome. Sequential biomarker analysis in humans with or without MOF is consistent with this model. This study is registered on https://clinicaltrials.gov at NCT03075605.NEW & NOTEWORTHY Acute pancreatitis is a sudden inflammatory response to pancreatic injury that may spread to systemic inflammation, multiorgan failure, and death in some patients. With the use of the predictions of a new mechanistic model, we compared patients with severe acute pancreatitis with or without multiorgan failure. All biomarkers of capillary leak and clinical features of multiorgan failure were accurately predicted. This provides a new paradigm for understanding and developing new treatments for patients with severe acute pancreatitis.

Dataset Information

Pathogen clonal expansion underlies multiorgan dissemination and organ-specific outcomes during murine systemic infection.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets