Purpose: We investigated the incidence of conjunctivitis in neonates admitted to the neonatal intensive care unit (NICU) or growing care unit (GCU) and examined the bacterial cultures isolated from the conjunctival sac at the time of onset of conjunctivitis. The findings were then compared to the delivery method, presence/absence of contamination at the time of birth, and other factors with respect to the time of onset of conjunctivitis to retrospectively determine the relationship between these factors and the onset.
Subjects and methods: The subjects comprised a total of 1,105 neonates admitted to the NICU or GCU of Tokyo Metropolitan Ohtsuka Hospital between April 2012 and March 2015. We examined the bacterial cultures isolated from the conjunctival sac of individual subjects who developed conjunctivitis. Moreover, with respect to a group of 17 subjects who developed conjunctivitis at 14 days or earlier after birth (Group I) and 15 subjects who developed conjunctivitis at 15-30 days after birth (Group II), the following factors were compared between the groups: gestational period, birth weight, delivery method, meconium staining of amniotic fluid, premature rupture of the membranes, and systemic administration of antibiotics.
Results: Conjunctivitis occurred in 37 (3.3％) subjects, and bacteria were isolated from 32 (86.5％) subjects as follows: 13 (33％) strains of methicillin-resistant coagulase-negative Staphylococcus, 10 (26％) strains of methicillin-sensitive S. aureus, 4 (10%) strains of coagulase-negative Staphylococcus, and 3 (8％) strains of Pseudomonas aeruginosa. Methicillin-resistant bacteria were observed in 14 of 32 (43.8％) subjects; the rate of the antibacterial drug administration was 96.6％ for the mother and 75.0％ for the infant. Compared with Group II, Group I had a longer gestational period (p＝0.023), a higher birth weight (p＝0.035), and a higher vaginal delivery rate (p＝0.036). There was no difference in the premature rupture of the membranes and meconium staining of amniotic fluid (p＝0.476).
Conclusions: In neonatal conjunctivitis occurring in NICU and GCU, neither the delivery method nor contamination at the time of birth was related to the onset of conjunctivitis. Many of the isolated bacterial strains, particularly the staphylococcal strains, were drug resistant. One of the causes was deemed to be the prophylactic administration of antibiotics.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 122: 444-452, 2018.