Coagulase-negative staphylococci: Role as pathogens

Coagulase-negative staphylococci have long been regarded as apathogenic but their important role as pathogens and their increasing incidence have been recognized and studied in recent years. Although specific virulence factor s are not as clearly established as they are in Staphylococcus aureus, it s eems clear that factors such as bacterial polysaccharide components are inv olved in attachment and/or persistence of bacteria on foreign materials. Co agulase-negative staphylococci are by far the most common cause of bacterem ia related to indwelling devices. Most of these infections are hospital-acq uired, and studies over the past several years suggest that they are often caused by strains that are transmitted among hospitalized patients. Other i mportant infections due to coagulase-negative staphylococci include central nervous system shunt infections, native or prosthetic valve endocarditis, urinary tract infections, and endophthalmitis. Intravenous treatment of sys temic infections is usually required because coagulase-negative staphylococ ci have become increasingly resistant to multiple antibiotics.