Wall teichoic acids of staphylococcus aureus limit recognition by the drosophila peptidoglycan recognition protein-SA to promote pathogenicity

The cell wall of gram-positive bacteria is a complex network of surface proteins,capsular polysaccharides and wall teichoic acids (wta) covalently linked to peptidoglycan (pg). the absence of wta has been associated with a reduced pathogenicity of staphylococcus aureus (s. aureus). here,we assessed whether this was due to increased detection of pg,an important target of innate immune receptors. antibiotic-mediated or genetic inhibition of wta production in s. aureus led to increased binding of the non-lytic pg recognition protein-sa (pgrp-sa),and this was associated with a reduction in host susceptibility to infection. moreover,pgrp-sd,another innate sensor required to control wild type s. aureus infection,became redundant. our data imply that by using wta to limit access of innate immune receptors to pg,under-detected bacteria are able to establish an infection and ultimately overwhelm the host. we propose that different pgrps work in concert to counter this strategy. © 2011 atilano et al.