Biology subjects

Nelson, K. E.

Publications and source records attributed to Nelson, K. E..

3 recordsLinked to original sources

bioRxiv2018

Longitudinal Surveys Show that Urethral Catheters Harbor Recurrent Polymicrobial Biofilms with Cooperative and Competitive Behaviors Among Cohabitating Pathogens

The analysis of catheter biofilms (CBs) from patients with neurogenic bladder disorders revealed persistent colonization by polymicrobial communities. The recurrence of bacterial species in the CBs of sequentially replaced catheters suggests urothelial reservoirs responsible for recolonization of the catheter surface. Proteomic data for CB samples were indicative of chronic inflammation in the patients urinary tracts via neutrophil and eosinophil infiltration and epithelial cell exfoliation. These host defense pathways, effective in killing pathogens during uncomplicated urinary tract infection, failed to eliminate CBs. Intermittent antibiotic drug treatment had different outcomes: either replacement of drug-susceptible by drug-tolerant bacteria or transient microbial biomass reduction followed by resurgence of the previously colonizing bacteria. Proteins that sequester iron and zinc such as lactotransferrin, lipocalin-2 and calprotectin were abundant in the patients CBs and urine sediments. Indicative of a host-pathogen battle for bivalent metal ions, acquisition and transport systems for such ions were highly expressed by many organisms residing in CBs. Species part of the Enterococcaceae and Aerococcaceae families, generally not well-characterized in their ability to synthesize siderophores, frequently cohabitated biofilms dominated by siderophore-producing Enterobacteriaceae. In support of metal acquisition cooperativity, we noticed positive abundance correlations for a Proteus mirabilis yersiniabactin-type siderophore system and two Enterococcus faecalis ABC transporters. Distinct bacterial strains highly expressed known or putative cytotoxins that appeared to compromise the survival of co-resident bacteria, e.g. a P. mirabilis hemolysin and Pseudomonas aeruginosa type 6 secretion and pyoverdin biosynthesis systems. In conclusion, there is support for cooperative and competitive behaviors among bacteria cohabitating CBs.

microbiology↗

bioRxiv2018

Supragingival plaque microbiome ecology and functional potential in the context of health and disease

To address the question of how microbial diversity and function in the oral cavities of children relates to caries diagnosis, we surveyed the supragingival plaque biofilm microbiome in 44 juvenile twin pairs. Using shotgun sequencing, we constructed a genome encyclopedia describing the core supragingival plaque microbiome. Caries phenotypes contained statistically significant enrichments in specific genome abundances and distinct community composition profiles including strain-level changes. Metabolic pathways that are statistically associated with caries include several sugar-associated phosphotransferase systems, antimicrobial resistance, and metal transport. Numerous closely-related previously-uncharacterized microbes had substantial variation in central metabolism, including the loss of biosynthetic pathways resulting in auxotrophy, changing the ecological role. We also describe the first complete Gracilibacteria genomes from the human microbiome. Caries is a microbial community metabolic disorder that cannot be described by a single etiology and our results provide the information needed for next generation diagnostic tools and therapeutics for caries.

microbiology↗

bioRxiv2018

Microbiome disturbance and resilience dynamics of the upper respiratory tract in response to influenza A virus infection in analog hosts

Infection with influenza can be aggravated by bacterial co-infections, which often results in disease exacerbation because of host responses and cellular damage. The native upper respiratory tract (URT) microbiome likely plays a role, yet the effects of influenza infection on the URT microbiome are largely unknown. We performed a longitudinal study to assess the temporal dynamics of the URT microbiomes of uninfected and influenza virus-infected humans and ferrets. Uninfected human patients and ferret URT microbiomes had stable \"heathy ecostate\" communities both within and between individuals. In contrast, infected patients and ferrets exhibited large changes in bacterial community composition over time and between individuals. The \"unhealthy\" ecostates of infected individuals progressed towards the \"healthy ecostate\" over time, coinciding with viral clearance and recovery. Blooms of Pseudomonas were a statistically associated constant in the disturbed microbiomes of infected individuals. The dynamic and resilient nature of the microbiome during influenza virus infection in multiple hosts provides a compelling rationale for the maintenance of the microbiome homeostasis as a potential therapeutic target to prevent IAV associated bacterial co-infections.\n\nOne Sentence SummaryDynamics of the upper respiratory tract microbiome during influenza A virus infection

microbiology↗