Bacterial Contamination of Expressed Breast Milk in Neonatal Intensive Care Unit

The milks expressed from the mothers’ breast might be infected during squeeze, storage and/or transmission. The infection level has been reported as different in various studies up to 97 percent. The main purpose of this study is to determine the infection level and its relevant organisms as well as to specify drug allergy of the expressed milks from the mothers with their infant admitted to NICU ward. In this study, among the expressed milks from 80 mothers, were cultured each in an amount of 0.5-1cc and antibiotic discs selected for every strain was placed. The results indicate that 85 percent of samples were infected and dominant microorganisms were firstly Klebsiella (13.7%) and then S. epidermidis (12.5%). In addition, 95% of Gram negative bacteria strains were susceptible to imipenem. The most effective antibiotic on isolated staphylococci was ceftizoxime (46.6% resistance). The colony count in 32.4% gram negative bacteria and in 66.7% gram positive bacteria was between 104 to 105 CFU/ml and the remaining was above 105 CFU/ml (p=0.02). Furthermore, there was no significant relationship between bacterial infection of the expressed milks with the site of milk expressing (house or hospital), mode of expressing (by pump or hand), storage duration and the mother’s demographic characteristics including age and/or literacy. The studies show that infection prevalence in the milk samples was 85%; the most common infection factor was Klebsiella and then S. epidermidis that is indicative of high prevalence of hospital infection (nosocomial infection) in the infants ward.