Adherence characteristics of coagulase-negative staphylococci isolated from patients with infective endocarditis

* Department of Microbial Diseases, St John's institute of Dermatology Division of Microbiology. United Medical and Dental Schools, St Thomas' Hospital, London SE1 7EH Correspondence should be sent to Professor W. C. Noble. Received October 4, 1994 Accepted February 7, 1995 Coagulase-negative staphylococci isolated from patients with endocarditis were divided according to whether the infection was of native or of prosthetic valves and was acquired either in the community or in hospital. Comparisons were made with strains from intravenous line-associated bacteraemias. All strains were examined by direct and indirect adherence tests. Line-associated bacteraemia strains were more likely to produce slime and were more hydrophilic but were less likely to attach HEp2 tissue culture cells than were endocarditis strains, and almost equally likely to adhere to plastic and extracellular matrix proteins. Amongst the endocarditis strains, there was little difference in slime production but hospital-acquired or prosthetic-valve strains were more hydrophobic and more likely to adhere to silicone than were the native-valve or community-acquired strains. Exposure of extracellular matrix proteins on native valves due to a pre-existing non-infective heart condition may account for the selection of strains able to adhere to fibronectin or laminin.