The newborn conjunctival flora at the post delivery 24 hours

The aim of this study was to investigate the aerobic conjunctival flora of neonates and the effects of delivery type on conjunctival flora development in neonates who were born with normal spontaneous vaginal delivery (SVD) or elective caesarean section (C/S) and who were not given prophylactic antibiotic eye drops after birth.

This cross-sectional study included 95 healthy newborns. One day after the delivery, conjunctival samples were taken from newborns who were born with normal SVD or elective C/S, and not given prophylactic antibiotic eye drops after birth. Newborns with conjunctival hyperemia and discharge were excluded from study. Samples were plated in blood agar, EMB, and chocolate agar. These cultures were incubated at 37 °C for 24-48 h. Antibiotic sensitivity was evaluated using Kirby-Bauer disc diffusion method.

Staphylococcus aureus (S.aureus) growth was observed in 7 (70%) and coagulase negative staphylococcus (CNS) growth in 2 (20%) out of 10 eyes with bacterial growth in 9 culture positive newborns born with C/S. Two S.aureus strains were resistant to methicillin. On the other hand, CNS growth was observed in the conjunctival cultures of 17 out of 19 eyes with bacterial growth in 16 culture positive newborns born with SVD. In 2 eyes with CNS growth, there was also S.aureus growth. The positive cultures for S.aureus were significantly higher in the conjunctival cultures of neonates born with C/S compared to neonates born with SVD, where CNS growth was significantly lower (P = 0.002). All isolates were susceptible to vancomycin, teicoplanin, and gatifloxacin. Two isolates were resistant to methicillin.

In deliveries with C/S, the newborn does not contact the vagina. This may result in changes of bacterial characteristic of the flora. Culture positivity for S.aureus was higher in C/S compared to SVD, which may be important in case neonatal conjunctivitis develops.