Clinical characteristics and <i>ompA</i> serovar correlation in adult inclusion conjunctivitis: a cohort study in China.

Abstract

Adult inclusion conjunctivitis (AIC) caused by non-trachomatous <i>Chlamydia trachomatis</i> is often under-recognised due to variable and non-specific clinical features. This study aimed to describe its clinical and laboratory characteristics, <i>ompA</i> serotype distribution, and their association with clinical presentation and outcome. This retrospective cohort study included 22 patients with laboratory-confirmed AIC diagnosed at a tertiary eye centre between February 2023 and January 2026. Clinical signs were graded using a structured conjunctival scoring system. Diagnosis was based on conjunctival cytology, nucleic acid amplification testing and cell culture. <i>C. trachomatis ompA</i> genotyping was performed by PCR and sequencing with phylogenetic analysis. Patients were classified into serovar D and non-D groups, and clinical severity scores and time to resolution were compared using the Mann-Whitney U test. Patients presented with subacute or chronic conjunctivitis with variable conjunctival hyperaemia, follicular reaction, papillary hypertrophy and discharge. <i>ompA</i> genotyping revealed a heterogeneous serovar distribution, with serovar D predominating. Overall clinical scores at presentation were higher in patients with non-D serovars than in those with serovar D (p<0.05), while only papillary reaction differed among individual signs. Time to clinical resolution after standard antibiotic therapy varied but did not differ significantly between groups. This study provides a clinical and molecular profile of AIC and highlights variability across ompA serotypes. By generating data from a Chinese cohort, it helps address the limited evidence base in this setting and may support improved clinical recognition and future genotype-phenotype research.