Failure of erythromycin ointment for postnatal ocular prophylaxis of chlamydial conjunctivitis.

Chlamydia trachomatis is the most common pathogen associated with conjunctivitis during early infancy in the United States. During a 13-month interval at our medical center 4834 infants were born, 311 of whom (6.4%) had conjunctival specimens tested for chlamydial antigen before the age of 12 weeks. In 44 (14% of all tested infants, 0.9% of live births) chlamydial antigen was present. Because the rate of asymptomatic maternal chlamydial endocervical colonization is estimated to be 26% at our institution (previous prospective study), we calculated a minimal failure rate for erythromycin ocular prophylaxis of from 7 to 19.5%. A subsequent case-control study revealed that mothers of infants with chlamydial conjunctivitis were more likely to be primiparous (P = 0.03) and experience longer duration of rupture of membranes before delivery (P = 0.046). We conclude that a substantial percentage of infants exposed to Chlamydia develop chlamydial conjunctivitis despite receiving erythromycin ocular prophylaxis.