PCR detection and molecular identification of Chlamydiaceae species

Recent taxonomic developments, based on 16s and 23s rRNA gene sequences, ha ve divided the family Chlamydiaceae into two genera and nine species, of wh ich five have been found to infect humans. Few simple methods are available to detect and identify all species sensitively and specifically. In this s tudy the suitability of the omp2 gene ag a target for molecular identificat ion of Chlamydiaceae is demonstrated. Phylogenetic analysis of partial omp2 gene sequences from all nine species agrees with the recently published ta xonomic changes based on the ribosomal genes. The use of a family-specific PCR primer pair, which is able to amplify the 5' end of the omp2 gene from all Chlamydiaceae except some Chlamydophila pecorum strains, is described. Identification of all nine species was achieved using restriction fragment length polymorphism analysis with a single enzyme, AluI confirmed by DNA se quencing. A PCR enzyme-linked oligonucleotide assay was developed which can detect a single chlamydial genome and may be applied to DNA extracts from any specimen or culture for the detection of single or mixed human chlamydi al infection.