[A routine prospective survey process to detect nosocomial bacterial colonization in a neonatal unit: risk factors...

A systematic analysis of weekly nasal and rectal swabs was carried out in a neonatal unit in order to detect colonization with multiresistant bacteria (MRB).

During a 6-month period, rectal and nasal samples were taken in 187 consecutively hospitalized newborns, the day of the admission (day 0) and every week until discharge, in order to detect MRB, mainly methicillin-resistant coagulase negative staphylococci (MRCoNS), Staphylococcus aureus and multi-resistant Gram-negative bacilli.

Among 187 infants, 50 were already colonized at entrance and excluded from the study. In others, 49 (35%) were colonized by at least one MRB, with a total of 71 strains isolated. The most frequent was MRCoNS, especially Staphylococcus epidermidis (66.1%). Gram-negative bacilli accounted for 9.8%. Colonization began earlier with MRCoNS than with Gram-negative bacilli, 7.8 +/- 6 vs. 15.5 +/- 16 days, P=0.004, and finished earlier 22.7 +/- 15 vs. 38.5 +/- 16 days, P=0.03. Colonized children exhibited by univariate analysis a lower birth weight, more frequent parenteral nutrition or previous hospitalization in a neonatal unit and a younger age at admission. Odds ratio for colonization were 4.06 for prematurity and 43.83 for a previous hospitalization. MRCoNS at days 15 (P <0.05) and 22 (P <0.05) were correlated with the empiric use of antibiotics. No nosocomial infection occurred during the study.

A high rate of newborns were colonized with MRB in our unit, especially MRCoNS, acquired earlier than Gram-negative bacilli, with a favoring action of empiric antibiotherapy.