Effects of antenatal antibiotic exposure on clinical characteristics and pathogen distribution in neonatal early-onset sepsis

Abstract

Objective To investigate the incidence and pathogen distribution of neonatal early-onset sepsis (EOS) following exposure to antenatal antibiotics. Methods One hundred and eighty-four neonates who were admitted to Maternal and Child Care Hospital of Xiamen and identified as having EOS from January 2010 to December 2015 were enrolled. The clinical data were retrospectively analyzed. According to antenatal antibiotic exposure time, the infants were divided into the antibiotics group (≥4 hours) and the control group (<4 hours). Women in late pregnancy (35-37 weeks of gestation) underwent group B Streptococcus (GBS) screening using standard bacterial culture beginning from Janaury 2014 as screening group. Intrapartum antibiotic prophylaxis was given if the GBS culture was positive. Infants delivered before January 2014 were included in the no-screening group. Pathogen distribution and the difference in drug resistance between the two groups were compared by a two-independent samples t-test and Chi-square test. Results In the antibiotics group, the percentages of birth weight lower than 2 500 g, preterm infants, asphyxia, and positive rates of GBS and blood culture were 24.3%(17/70), 14.3% (10/70), 2.9% (2/70), 7.1% (5/70) and 70.0% (49/70), respectively, and were significantly lower than those in the control group [39.5%(45/114), 28.1% (32/114), 14.9% (17/114), 19.3% (22/114) and 88.6% (101/114), respectively] (χ2=4.478, 4.678, 6.807, 5.118 and 9.957, all P 0.05). Compared with the no-screening group, the positive rate of GBS decreased [7.6% (5/66) vs 18.6% (22/118)] and the positive rate of fungal infection increased [7.6% (5/66) vs 1.7% (2/118)] in the screening group (χ2=4.141, P=0.042; χ2=4.000, P=0.046). The distribution of other pathogenic bacteria such as coagulase-negative Staphylococci and E. coli was not significantly different between the two groups (P>0.05, respectively). Drug resistance rates of Staphylococcus (Staphylococcus aureus and coagulase-negative Staphylococcus) to oxacillin and piperacillin-sulbactam were higher in the screening group than in the no-screening group [82.6% (19/23) vs 52.9% (18/34), χ2=5.302; 78.3% (18/23) vs 47.1% (16/34), χ2=5.549; both P<0.05], and no vancomycin resistant bacterial strains were found. Conclusions Antenatal antibiotic exposure may be effective in reducing the occurrence of prematurity, asphyxia,and GBS infection, but it increases the rate of fungal infection, and is not effective in reducing the incidence of complications and mortality or in changing the distribution of the other pathogens in EOS. Rational indications and timing of antenatal antibiotic exposure should be taken into consideration to reduce drug resistance. Key words: Sepsis; Antibiotic prophylaxis; Prenatal care; Infant, newborn