Find in Library

The biofilm component poly-<i>N</i>-acetylglucosamine (PNAG) is an important virulence determinant in medical-device-related infections caused by ESKAPE group pathogens including Gram-positive <i>Staphylococcus aureus</i> and Gram-negative <i>Acinetobacter baumannii</i>. PNAG presentation on bacterial cell surfaces and its accessibility for host interactions are not fully understood. We employed a lectin microarray to examine PNAG surface presentation and interactions on methicillin-sensitive (MSSA) and methicillin-resistant <i>S. aureus</i> (MRSA) and a clinical <i>A. baumannii</i> isolate. Purified PNAG bound to wheatgerm agglutinin (WGA) and succinylated WGA (sWGA) lectins only. PNAG was the main accessible surface component on MSSA but was relatively inaccessible on the <i>A. baumannii</i> surface, where it modulated the presentation of other surface molecules. Carbohydrate microarrays demonstrated similar specificities of <i>S. aureus</i> and <i>A. baumannii</i> for their most intensely binding carbohydrates, including 3′ and 6′sialyllactose, but differences in moderately binding ligands, including blood groups A and B. An <i>N</i>-acetylglucosamine-binding lectin function which binds to PNAG identified on the <i>A. baumannii</i> cell surface may contribute to biofilm structure and PNAG surface presentation on <i>A. baumannii</i>. Overall, these data indicated differences in PNAG presentation and accessibility for interactions on Gram-positive and Gram-negative cell surfaces which may play an important role in biofilm-mediated pathogenesis.