Article

Direct Observation of Staphylococcus aureus Cell Wall Digestion by Lysostaphin

Unité de Chimie des Interfaces, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
Journal of bacteriology (Impact Factor: 2.81). 11/2008; 190(24):7904-9. DOI: 10.1128/JB.01116-08
Source: PubMed

ABSTRACT

The advent of Staphylococcus aureus strains that are resistant to virtually all antibiotics has increased the need for new antistaphylococcal agents. An example
of such a potential therapeutic is lysostaphin, an enzyme that specifically cleaves the S. aureus peptidoglycan, thereby lysing the bacteria. Here we tracked over time the structural and physical dynamics of single S. aureus cells exposed to lysostaphin, using atomic force microscopy. Topographic images of native cells revealed a smooth surface
morphology decorated with concentric rings attributed to newly formed peptidoglycan. Time-lapse images collected following
addition of lysostaphin revealed major structural changes in the form of cell swelling, splitting of the septum, and creation
of nanoscale perforations. Notably, treatment of the cells with lysostaphin was also found to decrease the bacterial spring
constant and the cell wall stiffness, demonstrating that structural changes were correlated with major differences in cell
wall nanomechanical properties. We interpret these modifications as resulting from the digestion of peptidoglycan by lysostaphin,
eventually leading to the formation of osmotically fragile cells. This study provides new insight into the lytic activity
of lysostaphin and offers promising prospects for the study of new antistaphylococcal agents.

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Available from: Marie-Paule Mingeot-Leclercq
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    • "Other strategies were developed to overcome this difficulty; cells were immobilized in gelatin (Gad and Ikai 1995) or trapped into the pores of polycarbonate filters (Touhami et al. 2003a). These techniques have been widely used over the recent years (Francius et al. 2008; Alsteens et al. 2008; Dague et al. 2008b; Gilbert et al. 2007); however, it can lead to tip pollution in the case of gelatin trapping, or it can submit cells to mechanical forces in the case of cells trapped in pores. Also, both techniques are time-consuming because cells are spread all over the sample and can be quite difficult to find. "
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