An efficient moments-based inference method for within-host bacterial infection dynamics.

Over the last ten years, isogenic tagging (IT) has revolutionised the study of bacterial infection dynamics in laboratory animal models. However, quantitative analysis of IT data has been hindered by the piecemeal development of relevant statistical models. The most promising approach relies on stoc...

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Main Authors: David J Price, Alexandre Breuzé, Richard Dybowski, Piero Mastroeni, Olivier Restif
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2017-11-01
Series:PLoS Computational Biology
Online Access:https://doi.org/10.1371/journal.pcbi.1005841
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author David J Price
Alexandre Breuzé
Richard Dybowski
Piero Mastroeni
Olivier Restif
author_facet David J Price
Alexandre Breuzé
Richard Dybowski
Piero Mastroeni
Olivier Restif
author_sort David J Price
collection DOAJ
description Over the last ten years, isogenic tagging (IT) has revolutionised the study of bacterial infection dynamics in laboratory animal models. However, quantitative analysis of IT data has been hindered by the piecemeal development of relevant statistical models. The most promising approach relies on stochastic Markovian models of bacterial population dynamics within and among organs. Here we present an efficient numerical method to fit such stochastic dynamic models to in vivo experimental IT data. A common approach to statistical inference with stochastic dynamic models relies on producing large numbers of simulations, but this remains a slow and inefficient method for all but simple problems, especially when tracking bacteria in multiple locations simultaneously. Instead, we derive and solve the systems of ordinary differential equations for the two lower-order moments of the stochastic variables (mean, variance and covariance). For any given model structure, and assuming linear dynamic rates, we demonstrate how the model parameters can be efficiently and accurately estimated by divergence minimisation. We then apply our method to an experimental dataset and compare the estimates and goodness-of-fit to those obtained by maximum likelihood estimation. While both sets of parameter estimates had overlapping confidence regions, the new method produced lower values for the division and death rates of bacteria: these improved the goodness-of-fit at the second time point at the expense of that of the first time point. This flexible framework can easily be applied to a range of experimental systems. Its computational efficiency paves the way for model comparison and optimal experimental design.
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spelling doaj.art-fb48cfcd4764486a8e308d5ac1b9bbc82022-12-21T17:34:19ZengPublic Library of Science (PLoS)PLoS Computational Biology1553-734X1553-73582017-11-011311e100584110.1371/journal.pcbi.1005841An efficient moments-based inference method for within-host bacterial infection dynamics.David J PriceAlexandre BreuzéRichard DybowskiPiero MastroeniOlivier RestifOver the last ten years, isogenic tagging (IT) has revolutionised the study of bacterial infection dynamics in laboratory animal models. However, quantitative analysis of IT data has been hindered by the piecemeal development of relevant statistical models. The most promising approach relies on stochastic Markovian models of bacterial population dynamics within and among organs. Here we present an efficient numerical method to fit such stochastic dynamic models to in vivo experimental IT data. A common approach to statistical inference with stochastic dynamic models relies on producing large numbers of simulations, but this remains a slow and inefficient method for all but simple problems, especially when tracking bacteria in multiple locations simultaneously. Instead, we derive and solve the systems of ordinary differential equations for the two lower-order moments of the stochastic variables (mean, variance and covariance). For any given model structure, and assuming linear dynamic rates, we demonstrate how the model parameters can be efficiently and accurately estimated by divergence minimisation. We then apply our method to an experimental dataset and compare the estimates and goodness-of-fit to those obtained by maximum likelihood estimation. While both sets of parameter estimates had overlapping confidence regions, the new method produced lower values for the division and death rates of bacteria: these improved the goodness-of-fit at the second time point at the expense of that of the first time point. This flexible framework can easily be applied to a range of experimental systems. Its computational efficiency paves the way for model comparison and optimal experimental design.https://doi.org/10.1371/journal.pcbi.1005841
spellingShingle David J Price
Alexandre Breuzé
Richard Dybowski
Piero Mastroeni
Olivier Restif
An efficient moments-based inference method for within-host bacterial infection dynamics.
PLoS Computational Biology
title An efficient moments-based inference method for within-host bacterial infection dynamics.
title_full An efficient moments-based inference method for within-host bacterial infection dynamics.
title_fullStr An efficient moments-based inference method for within-host bacterial infection dynamics.
title_full_unstemmed An efficient moments-based inference method for within-host bacterial infection dynamics.
title_short An efficient moments-based inference method for within-host bacterial infection dynamics.
title_sort efficient moments based inference method for within host bacterial infection dynamics
url https://doi.org/10.1371/journal.pcbi.1005841
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