Genetic relatedness of Gram-negative bacteria colonizing gut and skin of neonates and mother’s own milk

Objectivewe described colonization of mother’s own milk with gram-negative bacteria and its relationship with neonatal colonization.study designgram-negative bacteria isolated from weekly collected stool, skin and mother’s own milk of hospitalized preterm (n = 49) and healthy term neonates (n = 20) were genotyped. colonization-related factors were determined by logistic regression.resultsgram-negative bacteria were isolated from mother’s own milk of 22.4% (n = 11) and 15% (n = 3) of mothers of preterm and term neonates, respectively. according to pulsed-field gel electrophoresis genetically similar strains were present in mother’s own milk and gut of 8.2% (n = 4) of mother–preterm neonate, but none of mother–term neonate pairs. in three of four late-onset sepsis caused by gram-negative bacteria, colonization of gut, but not mother’s own milk, with invasive species preceded late-onset sepsis.conclusionscolonization of mother’s own milk with gram-negative bacteria is uncommon and transmission to neonatal gut may occur in less than one-tenth of neonate–mother pairs.