Genital chlamydial infection: association between clinical features, organism genotype and load

The association between the clinical features of genital chlamydial infection and organism genotype and load was evaluated. Chlamydial DNA was detected and quantified in genital swabs from 233 (7 %) of 3384 consecutive patients attending a genitourinary medicine clinic. The chlamydia-positive subcohort comprised 132 (57%) females and 101 (43%) males. Clinical features were present in 33% women and 72% men. The chlamydial load was found to be higher in women (median load: 5.6 log) than men (median load: 3.5 log). Single variable analysis failed to show a significant association between chlamydial load and clinical features (P value = 0.3). Owing to the limited amount of clinical material, information on chlamydial genotypes was available for 70% (n = 162) of chlamydia-positive patients. However, multivariable analysis of these samples did show a significant association between chlamydial load and clinical features (P value = 0.02). This discrepancy is most probably due to the difference in the amount of data analysed by single variable (data from 233 patients) and multivariable (data from 162 patients) analysis. The distribution of chlamydial genotypes was as follows: type E (46%), F (22%), D (8 %), K (8 %), G (7 %), J (4 %), I (1%) and H (0.6%). No statistically significant association was observed between chlamydial genotype and clinical features in either single variable (P value = 0.6) or multivariable (P value = 0.4) analysis. These findings suggest that chlamydial load and diversity in the ompA gene plays little, if any, role in the pathogenesis of genital chlamydial infection.