Which Chlamydia serotypes primarily cause Adult inclusion conjunctivitis?

• A. G-H
• B. E-F
• C. A-C
• D. D-K

Answer: (D)

Chlamydia trachomatis serotypes determine the site and type of disease. Adult inclusion conjunctivitis is caused by the serotypes in the D through K range. These serotypes are the mucosal, urogenital strains that can inoculate the eye from a genital infection, leading to conjunctival inflammation with mucopurulent discharge. Clinically, this often presents in adults with a recent or concurrent genital infection and can start unilaterally before involving both eyes. In contrast, serotypes A through C are associated with trachoma, a chronic conjunctival disease that can cause scarring, and serotypes L1 through L3 cause lymphogranuloma venereum. Therefore, the serotypes D through K are the ones most commonly responsible for adult inclusion conjunctivitis.