displays high transformation capacity with complete cloning vector integration into the chromosomal plasticity zone.

The obligate intracellular genus contains many pathogens with a negative impact on global health and economy. Despite recent progress, there is still a lack of genetic tools limiting our understanding of these complex bacteria. This study provides new insights into genetic manipulation of with the opportunistic porcine pathogen , the only chlamydial species naturally harboring an antibiotic resistance gene, originally obtained by horizontal gene transfer. is transmissible to humans, posing a potential public health concern. We report that can take up vectors that lack the native plasmid, a requirement for most chlamydial transformation systems described to date. Additionally, we show that , the most common cause for bacterial sexually transmitted infections and infectious blindness worldwide, can be transformed with vectors. Finally, the chromosomal region that harbors the resistance gene of is highly susceptible to complete vector integration.