Calcium Chloride-Mediated Transformation of Chlamydia trachomatis and Other Chlamydia spp.

Despite a high level of conservation within its core genome, the Chlamydia genus comprises various species that exhibit diverse pathogenic profiles. Genetic engineering techniques employing shuttle vectors are crucial tools for elucidating the pathogenesis of these obligate intracellular bacteria. In recent years, the introduction of calcium chloride-mediated transformation methods has significantly advanced genetic manipulation techniques for Chlamydia trachomatis. However, the efficiency of transformation using shuttle vectors, as well as plasmid maintenance, varies not only between Chlamydia species but also among strains within the same species, necessitating individually optimized protocols. In this chapter, we describe the entire process from vector preparation and transformation procedures to the clonal isolation of transformed Chlamydia species to facilitate future applications in genetic studies.