Rapid microarray-based genotyping of Chlamydia spp. strains from clinical tissue samples.

Pathogenic Chlamydia (C.) psittaci and C. trachomatis strains can be genotyped based on variations in the ompA genomic locus. In the present chapter, we describe rapid genotyping assays for both chlamydial agents using the ArrayStrip™ (AS) microarray platform. The test is targeting multiple discriminatory sites in the variable domains of the ompA gene by using 35 (C. psittaci) and 61 (C. trachomatis) oligonucleotide probes representing genotype-specific polymorphisms. In addition to discrimination among the established genotypes, this approach allows identification of atypical strains that were not accessible to typing using previously established techniques, such as PCR-RFLP or serotyping. The present DNA microarray assay can be conducted directly on clinical tissue samples and is suitable for tracing epidemiological chains and exploring the dissemination of particular genotypes. The procedure is easy to handle and economically affordable, and it allows genotyping of up to 32 clinical samples per day, thus lending itself for routine diagnosis as well.