Micrograph of S. aureus Skin Abscess (image) University of North Carolina Health Care Share Print E-Mail Caption Cell nuclei are stained magenta and polyamine producing macrophages are blue. The host is attempting to wall off the infection by laying down a surrounding layer of collagen (gold) and other matrix proteins. Credit Richardson Lab, UNC School of Medicine Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.