Staphylococcus epidermidis endocarditis and Staphylococcus epidermidis infection in an intensive care unit

Staphylococcus epidermidis are the most common agents of prosthetic valve endocarditis (PVE). S. epidermidis isolated from the blood stream of patients with PVE are almost invariably multiple resistant to antibiotics. Antibiotic treatment alone gives unsatisfactory results and carries a mortality rate of 70-80%. That is why early surgical treatment is recommended. S. epidermidis is a less common cause of endocarditis in non-surgical patients, accounting for approximately 5% of the cases, which are mostly patients with pre-existent valvular heart disease. Generally, isolates from the latter patients are sensitive to most antibiotics, and the mortality rate is considerably lower. Recently coagulase-negative staphylococci have emerged as causative agents of septicaemia in patients hospitalized in intensive care units. Especially premature infants of very low-birth weight (less than 1500 g) receiving parenteral nutrition appear to carry a high risk of acquiring this kind of septicaemia. Although the staphylococci isolated from the blood of these patients are the same as in patients with PVE, generally multiple resistant to antibiotics, prognosis is far better than in cases of PVE. In our study carried out in a neonatal intensive care unit, two risk factors for coagulase-negative staphylococcal septicaemia were identified. First, nearly 20% of parenteral nutrition fluids used in the unit were found to be contaminated with coagulase-negative staphylococci, and a significant association was established between septicaemia and the infusion of contaminated fluids. Moreover, opsonization of staphylococci in infant serum proved to be severely deficient. Since host defence to staphylococci is dependent on optimal opsonization of these microorganisms, this defence may be severely compromised in the premature neonate.(ABSTRACT TRUNCATED AT 250 WORDS)