Low-shear force associated with modeled microgravity and spaceflight does not similarly impact the virulence of notable bacterial pathogens

Jason A. Rosenzweig, Sandeel Ahmed, John Eunson, Ashok K. Chopra

Research output: Contribution to journalReview articlepeer-review

41 Scopus citations


As their environments change, microbes experience various threats and stressors, and in the hypercompetitive microbial world, dynamism and the ability to rapidly respond to such changes allow microbes to outcompete their nutrient-seeking neighbors. Viewed in that light, the very difference between microbial life and death depends on effective stress response mechanisms. In addition to the more commonly studied temperature, nutritional, and chemical stressors, research has begun to characterize microbial responses to physical stress, namely low-shear stress. In fact, microbial responses to low-shear modeled microgravity (LSMMG), which emulates the microgravity experienced in space, have been studied quite widely in both prokaryotes and eukaryotes. Interestingly, LSMMG-induced changes in the virulence potential of several Gram-negative enteric bacteria, e.g., an increased enterotoxigenic Escherichia coli-mediated fluid secretion in ligated ileal loops of mice, an increased adherent invasive E. coli-mediated infectivity of Caco-2 cells, an increased Salmonella typhimurium-mediated invasion of both epithelial and macrophage cells, and S. typhimurium hypervirulence phenotype in BALB/c mice when infected by the intraperitoneal route. Although these were some examples where virulence of the bacteria was increased, there are instances where organisms became less virulent under LSMMG, e.g., hypovirulence of Yersinia pestis in cell culture infections and hypovirulence of methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, and Listeria monocytogenes in a Caenorhabditis elegans infection model. In general, a number of LSMMG-exposed bacteria (but not all) seemed better equipped to handle subsequent stressors such as osmotic shock, acid shock, heat shock, and exposure to chemotherapeutics. This mini-review primarily discusses both LSMMG-induced as well as bona fide spaceflight-specific alterations in bacterial virulence potential, demonstrating that pathogens’ responses to low-shear forces vary dramatically. Ultimately, a careful characterization of numerous bacterial pathogens’ responses to low-shear forces is necessary to evaluate a more complete picture of how this physical stress impacts bacterial virulence since a “one-size-fits-all” response is clearly not the case.

Original languageEnglish (US)
Pages (from-to)8797-8807
Number of pages11
JournalApplied Microbiology and Biotechnology
Issue number21
StatePublished - Nov 2014
Externally publishedYes


  • High aspect ratio vessel (HARV)
  • Hypervirulence
  • Low shear modeled microgravity (LSMMG)
  • Murine infections

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology


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