Resistant Nosocomial Enterococcal Infections

Enterococcus faecalis, formerly classified as Streptococcus faecalis, belongs to Lancefield group D and is frequently isolated from nosocomial infections. Of the nosocomial infections reported to the Centers for Disease Control (CDC) in its National Nosocomial Infection Survey (NNIS), enterococci were isolated from 11% of cases. Frequently, E. faecalis is recovered as one of several kinds of bacteria causing infections complicating abdominal or pelvic surgery; in such situations, its role is difficult to assess. On the other hand, it is clearly a pathogen when it is isolated from a normally sterile site, such as the urinary tract, serous cavities, the subarachnoid space, or the blood. Enteroccus spp are regarded as a separate genus based on DNA homology; they are identified in the clinical microbiology laboratory by their ability to grow in media containing 40% bile, cleave esculin, and grow in broth containing 6.5% NaCl. Most laboratories do not attempt to speciate enterococci. Enterococci currently account for 9% of all nosocomial bacteremias that occur at the University of Michigan Hospital and 14% of all bacteremias that occur at the Ann Arbor Veterans Administration Hospital.