Otitis media (OM) is a common polymicrobial infection of the middle ear in children under the age of 15 years. A widely used experimental strategy to analyse roles of specific phenotypes of bacterial pathogens of OM is to study changes in co-infection kinetics of bacterial populations in animal models when a wild-type bacterial strain is replaced by a specific isogenic mutant strain in the co-inoculating mixtures. As relationships between the OM bacterial pathogens within the host are regulated by many interlinked processes, connecting the changes in the co-infection kinetics to a bacterial phenotype can be challenging. We investigated middle ear co-infections in adult chinchillas (Chinchilla lanigera) by two major OM pathogens: non-typeable Haemophilus influenzae (NTHi) and Moraxella catarrhalis (Mcat), as well as isogenic mutant strains in each bacterial species. We analysed the infection kinetic data using Lotka-Volterra population dynamics, maximum entropy inference and Akaike information criteria-(AIC)-based model selection. We found that changes in relationships between the bacterial pathogens that were not anticipated in the design of the co-infection experiments involving mutant strains are common and were strong regulators of the co-infecting bacterial populations. The framework developed here allows for a systematic analysis of host-host variations of bacterial populations and small sizes of animal cohorts in co-infection experiments to quantify the role of specific mutant strains in changing the infection kinetics. Our combined approach can be used to analyse the functional footprint of mutant strains in regulating co-infection kinetics in models of experimental OM and other polymicrobial diseases.
Keywords: Akkaike information criterion; Condorcet winner; Lotka–Volterra; maximum entropy estimation; otitis media; polymicrobial infection.
Conflict of interest statement
The authors declare no competing interests.
Synergistic effect of adenovirus type 1 and nontypeable Haemophilus influenzae in a chinchilla model of experimental otitis media.Infect Immun. 1994 May;62(5):1710-8. Infect Immun. 1994. PMID: 8168932 Free PMC article.
Genetic requirement for pneumococcal ear infection.PLoS One. 2007 Aug 13;3(8):e2950. doi: 10.1371/journal.pone.0002950. PLoS One. 2007. PMID: 18670623 Free PMC article.
Association between early bacterial carriage and otitis media in Aboriginal and non-Aboriginal children in a semi-arid area of Western Australia: a cohort study.BMC Infect Dis. 2012 Dec 21;12:366. doi: 10.1186/1471-2334-12-366. BMC Infect Dis. 2012. PMID: 23256870 Free PMC article.
Otitis media: the chinchilla model.Microb Drug Resist. 1999 Spring;5(1):57-72. doi: 10.1089/mdr.1999.5.57. Microb Drug Resist. 1999. PMID: 10332723 Review.
Predominant Bacteria Detected from the Middle Ear Fluid of Children Experiencing Otitis Media: A Systematic Review.PLoS One. 2016 Mar 8;11(3):e0150949. doi: 10.1371/journal.pone.0150949. eCollection 2016. PLoS One. 2016. PMID: 26953891 Free PMC article. Review.
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