Chlamydia abortus infects sheep causing ovine enzootic abortion (OEA). The commercial inactivated vaccines have low efficacy and the live vaccines can cause OEA.

We isolated strain 84/2334 from a parrot and classified it initially as Chlamydia psittaci. However, in depth genomic analysis revelaed that the strain actually belongs to a new avian C. abortus genotype. Sheep C.abortus strains have no plasmid, but 84/2334 has a plasmid, just as in avian C. psittaci. 84/2334 can thus genetically be manipulated via its plasmid leading to a novel OEA vaccin. However, before creating mutant 84/2334, we do need to know if 84/2334 is biologically similar to 'sheep C. abortus', and thus suitable for vaccin engineering. For this we will: i) compare their infection dynamics (growth kinetics, live-cell imaging, electron microscopy), ii) their RNAseq profiles (pahogen and host cell) and iii) modulation of their host cell epigenome in vitro.