Author:
Secor Patrick R.,Michaels Lia A.,Ratjen Anina,Jennings Laura K.,Singh Pradeep K.
Abstract
Bacteria causing chronic infections are generally observed living in cell aggregates suspended in polymer-rich host secretions, and bacterial phenotypes induced by aggregated growth may be key factors in chronic infection pathogenesis. Bacterial aggregation is commonly thought of as a consequence of biofilm formation; however the mechanisms producing aggregation in vivo remain unclear. Here we show that polymers that are abundant at chronic infection sites cause bacteria to aggregate by the depletion aggregation mechanism, which does not require biofilm formation functions. Depletion aggregation is mediated by entropic forces between uncharged or like-charged polymers and particles (e.g., bacteria). Our experiments also indicate that depletion aggregation of bacteria induces marked antibiotic tolerance that was dependent on the SOS response, a stress response activated by genotoxic stress. These findings raise the possibility that targeting conditions that promote depletion aggregation or mechanisms of depletion-mediated tolerance could lead to new therapeutic approaches to combat chronic bacterial infections.
Funder
Cystic Fibrosis Foundation
HHS | NIH | National Institute of Allergy and Infectious Diseases
HHS | NIH | National Institute of General Medical Sciences
Burroughs Wellcome Fund
Publisher
Proceedings of the National Academy of Sciences