Prominent colony morphologies of Salmonella Enteritidis. TOP. Multiple colonies, 10 per plate, were grown for five days at ambient temperature following a 16 hr incubation at 37°C. BOTTOM. Colonies are magnified. Inset markers are 10 mm. This picture is reprinted with permission from Avian Diseases . Copyright is property of the federal government. A. PT4 S. Enteritidis strain 22079, with weak slow biofilm formation; B. PT13a S. Enteritidis strain 21027, with strong rapid biofilm formation; C. PT13a S. Enteritidis strain 21046, with no discernible biofilm formation.