Infection by staphylococcus (s) epidermidis is a common problem in infants who are on total parenteral nutrition for long periods. The purpose of this in- vitro study is to see whether two commonly used pediatric aminoacid mixtures differ in their effect on growth of s. epidermidis.

Two parenteral solutions were prepared in 5% dextrose by the pharmacy. One with 1% Aminosyn and another containing 1% Trophamine, each to provide lgm of protein and 100 ml of fluids per kilogram per day. The solutions were incubated with s. epidermidis and growth of bacteria was observed. The bacterial colony count was lower with 1% Aminosyn and 5% dextrose. Three more solutions were prepared, 3% Trophamine, 3% Aminosyn and 10% dextrose. These solutions were similarly incubated with s.epidermidis and the growth of bacteria was observed. The 3% Aminosyn had lower bacterial growth.

It appears that Aminosyn-PF may have protective effect against growth of s. epidermidis.