A cluster of coagulase-negative staphylococcal bacteremias associated with peripheral vascular catheter colonization in a neonatal intensive care unit

Abstract Background: A cluster of six neonatal cases of coagulase-negative staphylococcal bacteremias occurred in a Los Angeles County neonatal intensive care unit in March 1989. Methods: A retrospective cohort study assessed the impact of host-and delivery-related variables, length of hospitalization, duration of antibiotic treatment, performance or duration of invasive procedures, and staffing variables on risk of coagulase-negative staphylococcal bacteremia. Results: Unstratified analyses yielded eight risk factors with risk ratios greater than 2. After stratification by gestational age (less than 29 weeks) and low birth weight (less than 1500 gm), frequency of blood transfusions, duration of respiratory therapy, heparin lock and central vascular line placement, and hyperalimentation remained associated with elevated risk. Two species were identified, arguing against a common source of infection. Of four cohort months with more than 15 very low birth weight infants in the neonatal intensive care unit, an elevation of coagulase-negative staphylococcus-positive blood cultures and diagnosed bacteremias occurred in only two. Conclusions: This cluster opf coagulase-negative staphylococcal bacteremia was probably caused by frequent manipulation of catheters in neonates who were at heightened risk because of low birth weight and prematurity.