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Translocation and dissemination of commensal bacteria in post-stroke infection
Dragana Stanley1, Linda J Mason2, Kate E Mackin3,4
1School of Medical and Applied Sciences, Central Queensland University, Rockhampton, Queensland, Australia.
Abstract:
Bacterial infection is highly prevalent in patients who have had a stroke. Despite the potential contribution of micro-aspiration in post-stroke pneumonia, we found that the majority of the microorganisms detected in the patients who developed infections after having a stroke were common commensal bacteria that normally reside in the intestinal tracts. In a mouse model of ischemic stroke, post-stroke infection was only observed in mice that were born and raised in specific-pathogen-free facilities; this was not seen in mice that were born and raised in germ-free facilities. Using high-throughput 16S rRNA gene amplicon sequencing and bioinformatics analyses, we provide evidence demonstrating that the source of the bacteria forming the microbial community in the lungs of post-stroke mice was indeed the host small intestine. Additionally, stroke-induced gut barrier permeability and dysfunction preceded the dissemination of orally inoculated bacteria to peripheral tissues. This study identifies a novel pathway in which stroke promotes the translocation and dissemination of selective strains of bacteria that originated from the host gut microbiota.
Insights
Stroke can lead to bacterial infections originating from the gut. This study reveals how stroke impairs the gut barrier, allowing intestinal bacteria to spread to other organs, causing infection.
Area of Science:
- Microbiology
- Immunology
- Neurology
Background:
- Bacterial infections are common in stroke patients.
- Micro-aspiration is a suspected cause of post-stroke pneumonia.
- Commensal gut bacteria are frequently detected in post-stroke infections.
Purpose of the Study:
- To investigate the source of bacterial infections following ischemic stroke.
- To elucidate the mechanism of bacterial translocation from the gut to peripheral tissues post-stroke.
Main Methods:
- Utilized a mouse model of ischemic stroke.
- Employed high-throughput 16S rRNA gene amplicon sequencing and bioinformatics.
- Assessed gut barrier permeability and bacterial dissemination.
Main Results:
- Post-stroke infections in mice were linked to gut microbiota, not observed in germ-free conditions.
- The small intestine was identified as the source of lung microbial communities in post-stroke mice.
- Stroke induced gut barrier dysfunction, preceding bacterial translocation.
Conclusions:
- Stroke promotes the translocation and dissemination of gut-originating bacteria.
- A novel pathway involving stroke-induced gut dysbiosis and bacterial spread is identified.
- Findings highlight the gut microbiota's role in post-stroke infections.
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HAIs significantly increase the cost of health care. Extended stays in healthcare institutions, increased disability, increased costs of medications, including specialized antibiotics, and prolonged recovery times add to the patient's expenses and the healthcare institution and funding bodies.