Chlamydiae are pathogens that are transmitted through sexual contact and have been found to potentially survive for extended periods in the human gastrointestinal tract.
Chlamydiae are pathogens transmitted through sexual activity, and recent findings suggest they may remain in the human gut for quite some time. This discovery has been reported by researchers from Würzburg and Berlin in the journal PLOS Pathogens.
Individuals infected with chlamydia can pass the bacteria to others during unprotected sexual encounters. Typically, the initial symptoms are mild or even nonexistent, manifesting occasionally as itching in the vaginal, penile, or anal regions. If detected, this infection can be effectively treated with antibiotics. However, failure to address the infection can lead to significant health issues, including infertility and even cancer.
A common occurrence observed in clinical practice is when patients return to the doctor with a new chlamydia infection after successful antibiotic treatment; often, they are infected with the exact same bacterial strains as before.
“This suggests that the bacteria may find a safe spot in the body where they are not easily eradicated, creating a lasting reservoir that can reactivate later,” explains Professor Thomas Rudel, a chlamydia specialist and Head of the Chair of Microbiology at the Biocentre of Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany. This phenomenon is referred to as persistence and is concerning because the bacteria that linger in the body can become more resistant to antibiotics over time.
Intestinal Organoids Experimentally Infected with Chlamydia
Where do these bacteria persist? Studies using mouse models have shown that chlamydia can endure within the intestines of these animals. Similarly, it appears that in humans, the bacteria also thrive in this specific area. This was detailed by the research teams led by Thomas Rudel and Sina Bartfeld in the journal PLOS Pathogens. Professor Bartfeld was previously with JMU until 2021 and currently heads the Department of Medical Biotechnology at Technische Universität Berlin.
The researchers pinpointed the intestine as a persistent niche by utilizing lab-created miniature organs known as organoids. These organoids are structures made from human intestinal cells that closely resemble the actual organ in both structure and function.
The teams from Würzburg and Berlin attempted to infect the intestinal organoids with chlamydia. They found that the inner cell layer of the organoids demonstrated significant resistance to the bacteria: transmission only occurred when the cell epithelium was compromised. In contrast, the chlamydia were able to infect effectively from the bloodstream. “In this scenario, we continually observed the persistent forms of the bacteria, identifiable by their distinctive shapes under an electron microscope,” says Pargev Hovhannisyan from JMU, the lead author of the study.
Clinical Studies and Further Experiments Must Follow
Translated to human biology, this suggests that chlamydia infections leading to persistence may be difficult to acquire through the inner intestinal lining but can happen quite readily through the bloodstream. However, this needs to be verified through clinical studies, notes Thomas Rudel.
The subsequent step for Thomas Rudel and Sina Bartfeld is to investigate whether chlamydia preferentially target specific cell types for their persistence. This is a complex challenge, as the intestine contains hundreds of different cell types. It’s also possible that surrounding tissue factors contribute to persistence. These aspects, along with others, are set to be explored further.
