SEROTYPING AND GENOTYPING OF GENITAL CHLAMYDIA-TRACHOMATIS ISOLATES REVEAL VARIANTS OF SEROVAR-BA, SEROVAR-G, AND SEROVAR-J AS CONFIRMED BYOMP1 NUCLEOTIDE-SEQUENCE ANALYSIS

Urogenital isolates (n = 93) of Chlamydia trachomatis were differentia ted into serovars and variants by serotyping with monoclonal antibodie s and genotyping by restriction fragment length polymorphism (RFLP) an alysis of the PCR-amplified omp1 gene, respectively. The types of 87 o f the 93 isolates (94%) were identical, as determined by both methods. Among these 87 isolates, 3 isolates were identified as the recently d escribed new serovariant Ga/IOL-238 by omp1 nucleotide sequence analys is of the variable domains. Of the remaining six isolates, three isola tes serotyped as both L2 and Ba but were identified as Ba/A-7 by genot yping by RFLP analysis of omp1. The omp1 nucleotide sequences of varia ble domains VD1, VD2, and VD4 of these urogenital Ba strains were iden tical to the sequences of the variable domains of Ba/J160, an ocular B a type. The three remaining isolates were serotyped as J, but the patt erns obtained by RFLP analysis of omp1, which were identical for the t hree isolates, differed hom that of prototype serovar J/UW36. omp1 nuc leotide sequence analysis' revealed that these strains are genovariant s of serovar J/UW36. Nucleotide sequence differences between serovar J /UW36 and this J genovariant, designated Jv, were found in both variab le and constant domains. In conclusion, this study shows that the PCR- based genotyping of clinical C. trachomatis isolates by RFLP analysis of omp1 has a higher discriminatory power and is more convenient than serotyping. Variants of C. trachomatis serovars Ba, G, and J were iden tified and characterized.