The mother as most important risk factor for colonization of very low birth weight (VLBW) infants with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E)

This study aimed to determine the prevalence of and risk factors for colonization with extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) and methicillin-resistant Staphylococcus aureus (MRSA) in very low birth weight (VLBW; < 1500 g) infants and their mothers. This investigation was conducted in the perinatal centre at the Charit, Berlin between May 2012 and June 2013. VLBW infants and their mothers were screened for colonization with ESBL-E and MRSA. Demographic and clinical data were obtained from the German nationwide surveillance system for nosocomial infections in VLBW infants (NEO-KISS) and used to perform univariate and multivariate analyses. Of 209 VLBW infants, 12 (5.7%) were colonized with ESBL-E. Eighteen of 209 (8.6%) ESBL-E-tested neonates were related to an ESBL-E-positive mother. Univariate analysis, strain typing and multivariate analysis (OR 7.4, 95% CI 2.1-26.7, PaEuroS=aEuroS0.002) identified an ESBL-E-positive mother and maternal-neonatal transmission as a main source of colonization. The prevalence of MRSA was 2.3% (5 of 221) among VLBW infants. One of the 221 (0.5%) MRSA-tested neonates was related to an MRSA-positive mother. No risk factors for transmission of MRSA could be detected in this study. Our study demonstrated that maternal-neonatal transmission of ESBL-E from mother to child is an important risk factor for colonization of VLBW infants. As a consequence, routine ESBL-E screening of neonates and mothers should be considered as a means of reducing neonatal morbidity and mortality.