Death and transfiguration in static Staphylococcus epidermidis cultures

Schaudinn, C.; Stoodley, P.; Hall-Stoodley, L.; Gorur, A.; Remis, J.; Wu, S.; Auer, M.; Hertwig, S.; Guerrero-Given, D.; Hu, F. Z.; Ehrlich, G. D.; Costerton, J. W.; Robinson, D. H.; Webster, P.

Death and transfiguration in static Staphylococcus epidermidis cultures

2014

The overwhelming majority of bacteria live in slime embedded microbial communities termed biofilms, which are typically adherent to a surface. However, when several Staphylococcus epidermidis strains were cultivated in static liquid cultures, macroscopic aggregates were seen floating within the broth and also sedimented at the test tube bottom. Light- and electron microscopy revealed that early-stage aggregates consisted of bacteria and extracellular matrix, organized in sheet-like structures. Perpendicular under the sheets hung a network of periodically arranged, bacteria-associated strands. During the extended cultivation, the strands of a subpopulation of aggregates developed into cross-connected wall-like structures, in which aligned bacteria formed the walls. The resulting architecture had a compartmentalized appearance. In late-stage cultures, the wall-associated bacteria disintegrated so that, henceforth, the walls were made of the coalescing remnants of lysed bacteria, while the compartment-like organization remained intact. At the same time, the majority of strand-containing aggregates with associated culturable bacteria continued to exist. These observations indicate that some strains of Staphylococcus epidermidis are able to build highly sophisticated structures, in which a subpopulation undergoes cell lysis, presumably to provide continued access to nutrients in a nutrient-limited environment, whilst maintaining structural integrity.

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