Nanoscale Phenotypic Textures of Yersinia pestis Across Environmentally-Relevant Matrices.

Kanwal M Iqbal,Vamsi K Yadavalli,Massimo F Bertino,Muhammed R Shah,Christopher J Ehrhardt

doi:10.3390/microorganisms8020160

Kanwal M Iqbal, Vamsi K Yadavalli + Show 3 more

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https://doi.org/10.3390/microorganisms8020160

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Abstract

The persistence of bacterial pathogens within environmental matrices plays an important role in the epidemiology of diseases, as well as impacts biosurveillance strategies. However, the adaptation potentials, mechanisms for survival, and ecological interactions of pathogenic bacteria such as Yersinia pestis are largely uncharacterized owing to the difficulty of profiling their phenotypic signatures. In this report, we describe studies on Y. pestis organisms cultured within soil matrices, which are among the most important reservoirs for their propagation. Morphological (nanoscale) and phenotypic analysis are presented at the single cell level conducted using Atomic Force Microscopy (AFM), coupled with biochemical profiles of bulk populations using Fatty Acid Methyl Ester Profiling (FAME). These studies are facilitated by a novel, customizable, 3D printed diffusion chamber that allows for control of the external environment and easy harvesting of cells. The results show that incubation within soil matrices lead to reduction of cell size and an increase in surface hydrophobicity. FAME profiles indicate shifts in unsaturated fatty acid compositions, while other fatty acid components of the phospholipid membrane or surface lipids remained consistent across culturing conditions, suggesting that phenotypic shifts may be driven by non-lipid components of Y. pestis.

Highlights

Several non-spore-forming bacterial pathogens can persist in environmental matrices outside of transmission vectors or mammalian hosts for extended periods of time
Understanding the chemical and physical properties of Y. pestis cells that occur with survival in soil matrices is critical for elucidating uncharacterized aspects of the transmission life-cycles of plague
The goal of this study was to demonstrate a new approach to characterizing phenotypic signatures in bacterial pathogens in environmental matrices

Summary

Introduction

Several non-spore-forming bacterial pathogens can persist in environmental matrices outside of transmission vectors or mammalian hosts for extended periods of time. For Y. pestis in particular, survival and persistence in matrices such as soil has been hypothesized to contribute to infections of susceptible hosts [6], and the periodicity of plague epidemics in many parts of the world. A number of field observations and laboratory studies have demonstrated survival of Y. pestis in soil for periods ranging between days to months [7,8]. More recent case studies have shown viability of Y. pestis after several weeks in desert soil and that organisms are able to maintain virulence [5]. For other gram negative pathogens such as E. coli and B. pseudomallei, biochemical changes to the cell membrane and/or ultrastructure of the cell has been associated with soil-mediated survival [9,10], but this has not been investigated explicitly in Y. pestis

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