The 3D architecture of a bacterial swarm has implications for antibiotic tolerance

Swarming bacteria are an example of a complex, active biological system, where high cell density and super-diffusive cell mobility confer survival advantages to the group as a whole. Previous studies on the dynamics of the swarm have been limited to easily observable regions at the advancing edge of...

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Bibliographic Details
Published in:	Scientific reports 2018-10, Vol.8 (1), p.15823-11, Article 15823
Main Authors:	Partridge, Jonathan D, Ariel, Gil, Schvartz, Orly, Harshey, Rasika M, Be'er, Avraham
Format:	Article
Language:	eng
Subjects:	Antibiotic tolerance Antibiotics Bacteria Biosurfactants Cell density Cell migration Cell survival Chemotaxis Leukocyte migration Swarming
Online Access:	Get full text
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Summary:	Swarming bacteria are an example of a complex, active biological system, where high cell density and super-diffusive cell mobility confer survival advantages to the group as a whole. Previous studies on the dynamics of the swarm have been limited to easily observable regions at the advancing edge of the swarm where cells are restricted to a plane. In this study, using defocused epifluorescence video imaging, we have tracked the motion of fluorescently labeled individuals within the interior of a densely packed three-dimensional (3D) region of a swarm. Our analysis reveals a novel 3D architecture, where bacteria are constrained by inter-particle interactions, sandwiched between two distinct boundary conditions. We find that secreted biosurfactants keep bacteria away from the swarm-air upper boundary, and added antibiotics at the lower swarm-surface boundary lead to their migration away from this boundary. Formation of the antibiotic-avoidance zone is dependent on a functional chemotaxis signaling system, in the absence of which the swarm loses its high tolerance to the antibiotics.
ISSN:	2045-2322 2045-2322