Methods and compositions for detecting serotypes of

Disclosed are methods and compositions for conducting assays of samples utilizing polymerase chain reactions (“PCRs”) in the detection of serotypes of Chlamydia trachomatis capable of causing lymphogranuloma venereum (“LGV”). These assays take advantage of a deletion occurring in the cytotoxin gene locus specific to the L I, L II, and L serotypes. Each of these assays employs a first primer having a nucleotide sequence flanking one side of the deletion point and a second primer having a nucleotide sequence flanking the other side of the deletion point, wherein the first primer and the second primer are capable of hybridizing respectively to the plus strand and the minus strand of the genome of Chlamydia trachomatis during the PCR. Synthesis during the PCR of a sequence-specific amplicon containing this deletion point indicates that the sample contains nucleic acid specific to an LGV-causing serotype of Chlamydia trachomatis.