Erythromycin ointment for ocular prophylaxis of neonatal chlamydial infection

We compared the efficacy of erythromycin ophthalmic ointment vs 1% silver nitrate drops for the prevention of neonatal conjunctivitis or respiratory tract infection from Chlamydia trachomatis. The organism was isolated from the cervix of 67 (12%) of 572 pregnant women. They gave birth to 559 infants who were randomly assigned to either prophylaxis immediately after birth. Thirty-six of 60 infants born to Chlamydia-positive women received silver nitrate; 24 received erythromycin. Twelve (33%) of the 36 infants who received silver nitrate had chlamydial conjunctivitis, but none of the 24 infants who received erythromycin did. Ten (29%) of 36 infants receiving silver nitrate had chlamydial nasopharyngeal infection (three later had pneumonia), as opposed to five (21%) of 24 who received erythromycin (one had pneumonia). Thus, erythromycin ointment is effective in prevention of chlamydial conjunctivitis, but it may not reduce nasopharyngeal infection or subsequent pneumonia.