Determination of an Interaction Network between an Extracellular Bacterial Pathogen and the Human Host.

A major gap in understanding infectious diseases is the lack of information about molecular interaction networks between pathogens and the human host. causes the genital ulcer disease chancroid in adults and is a leading cause of cutaneous ulcers in children in the tropics. We developed a model in which human volunteers are infected on the upper arm with until they develop pustules. To define the and human interactome, we determined bacterial and host transcriptomic and host metabolomic changes in pustules. We found that transcripts were distinct from those in the inocula, as were host transcripts in pustule and wounded control sites. Many of the upregulated genes were found to be involved in ascorbic acid and anaerobic metabolism and inorganic ion/nutrient transport. The top 20 significantly expressed human pathways showed that all were involved in immune responses. We generated a bipartite network for interactions between host and bacterial gene transcription; multiple positively correlated networks contained genes involved in anaerobic metabolism and host genes involved with the immune response. Metabolomic studies showed that pustule and wounded samples had different metabolite compositions; the top ion pathway involved ascorbate and aldarate metabolism, which correlated with the transcriptional response and upregulation of host genes involved in ascorbic acid recycling. These data show that an interactome exists between and the human host and suggest that exploits the metabolic niche created by the host immune response. Dual RNA sequencing (RNA-seq) offers the promise of determining an interactome at a transcriptional level between a bacterium and the host but has yet to be done on any bacterial infection in human tissue. We performed dual RNA-seq and metabolomics analyses on wounded and infected sites following experimental infection of the arm with Our results suggest that survives in an abscess by utilizing l-ascorbate as an alternative carbon source, possibly taking advantage of host ascorbic acid recycling, and that also adapts by upregulating genes involved in anaerobic metabolism and inorganic ion and nutrient transport. To our knowledge, this is the first description of an interaction network between a bacterium and the human host at a site of infection.

Copyright © 2019 Griesenauer et al.