Inclusion conjunctivitis is caused by which organism and can be transmitted to newborns during birth?

• A. Neisseria gonorrhoeae
• B. Trachoma
• C. Chlamydia trachomatis
• D. Streptococcus pneumoniae

Answer: (C)

Inclusion conjunctivitis is caused by Chlamydia trachomatis, an intracellular bacterium that can be carried in the birth canal if a mother is infected. As the newborn passes through the birth canal, this organism can be transmitted to the infant’s eye, leading to conjunctivitis that typically appears about a week or two after birth and presents with mucopurulent discharge and conjunctival follicles. This vertical transmission distinction helps explain why this organism is the cause of neonatal conjunctivitis in this scenario. Neisseria gonorrhoeae can also cause neonatal conjunctivitis but it tends to present much sooner after birth and more aggressively. Trachoma, while also caused by Chlamydia trachomatis, involves different serotypes and is a chronic eye infection typically not acquired during birth. Therefore, the organism most associated with inclusion conjunctivitis and birth transmission is Chlamydia trachomatis.