UNIVERSITY OF VIRGINIA RESEARCHERS FOUND THAT PRIOR ANTIBIOTIC USE IMPAIRED SUBSEQUENT IMMUNE CELL FUNCTION IN CHILDREN. They first noticed that amebic colitis, a potentially fatal illness, was more severe in Bangladeshi children who had altered gut bacteria, usually occurring from prior antibiotic use. They then studied the problem in mice and found that antibiotic use impaired the ability of white blood cells to fight infection. The message is to only use antibiotics when they are necessary because their use can actually make subsequent infections worse.