Updating the relationship of Chlamydia pneumoniae with atherosclerotic cardiovascular diseases: a systematic review of reviews

Chlamydia pneumoniae is the etiologic agent of respiratory tract infections in humans, including community-acquired pneumonia, and has been associated with atherosclerotic cardiovascular diseases. The present systematic review of reviews aimed at answering important questions on the involvement of C. pneumoniae in the pathogenesis of atherosclerosis, its cellular and molecular mechanisms, and whether there is evidence of a causal relationship. The databases PubMed/Medline, Scopus, and Web of Science were searched for all review articles published from 2003 to the end of 2023. A total of 27 reviews, systematic reviews, and systematic reviews with metanalysis were included. Overall, current evidence suggests that C. pneumoniae is a biologically plausible candidate for the causation of atherosclerosis, albeit not all the 4 Koch postulates are fulfilled; oxidative stress and inflammation are the most likely pathogenic mechanisms mediated by C. pneumoniae. However, it is still unclear how the persistent form, responsible for chronic inflammation, fits into this etiopathogenetic scenario. In the future, the newly-designed transformation systems for the genomic manipulation of C. pneumoniae will surely help expand our knowledge on the role of this pathogen in atherogenesis.