“The number of patients colonized with Gram negative microorganisms … spp was similar in both treatment arms but ampicillin resulted in longer colonization duration (CD) of K. pneumonia (….012), AR Serratia spp (p = 0.012) and Candida spp (p = 0.02) and penicillin in … AR Acinetobacter spp (p = 0.001).”