Colonized infusate was detected in 18 (5%) of 413 i.v. sets; 9 (5%) of 177 sets were changed at 48 hours, and 9 (4%) of 236 sets were changed at 24 hours (p>0.05). A trend toward increased colonization of i.v. sets used to administer parenteral nutrition (19%) and, to a lesser extent, electrolytes (9%) was identified in the 48-hour group. Coagulase-negative staphylococci were the most frequently isolated microorganisms in the i.v. infusate