Association of genital infection with specific Chlamydia trachomatis serovars and race

Black race is an important risk marker for Chlamydia trachomatis genital infection. To define whether C. trachomatis serovars differ by ethnic distribution, a panel of monoclonal antibodies was used to serotype 934 urethral and 581 cervical isolates from patients attending a sexually transmitted diseases clinic over 2 years. The overall serovar distribution in cervical and urethral infections was comparable, with B class serovars predominating. Significantly higher inclusion counts were observed both in younger women and in nonblacks regardless of serovar. Serovar D was less frequent among blacks at the urethral site (P = .001), while serovar Ia was more frequent in blacks at both sites (urethral, P < .001; cervical, P = .02). These associations remained significant after adjusting for age and number of inclusion-forming units by multivariate analysis. Thus, specific serovars may be associated with particular racial groups; either behavioral or biologic factors could explain these findings.