Cotrimoxazole reduces systemic inflammation in HIV infection by altering the gut microbiome and immune activationOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study examined how long-term cotrimoxazole prophylaxis reduces systemic inflammation in HIV infection, a known independent driver of HIV-related mortality. Researchers investigated whether cotrimoxazole's clinical benefits could be explained by changes in the gut microbiome and intestinal inflammatory biomarkers, since subclinical enteropathogen carriage and enteropathy can drive systemic inflammation. They also used in vitro models of systemic and intestinal inflammation to isolate direct immune effects of cotrimoxazole from its antibiotic effects on gut bacteria.
Who was studied?
The study population was HIV-positive Ugandan and Zimbabwean children receiving antiretroviral therapy. Plasma inflammatory markers were compared between children randomized to continue cotrimoxazole (n = 144) versus stop it (n = 149). A smaller subset underwent gut microbiome and fecal biomarker analysis, with 36 children continuing cotrimoxazole compared to 36 stopping it.
What were the most important findings?
Plasma inflammatory markers were lower in children who continued cotrimoxazole compared to those who stopped, and this difference was not explained by clinical illness, HIV progression, or nutritional status. Overall gut microbiome composition was unchanged, but viridans group Streptococci and streptococcal mevalonate pathway enzymes were lower among children continuing cotrimoxazole. These microbial changes were associated with lower fecal myeloperoxidase, an intestinal inflammatory biomarker, and in vitro experiments showed cotrimoxazole had modest but consistent direct inhibitory effects on proinflammatory cytokine production.
What are the greatest implications of this study?
The findings suggest cotrimoxazole prophylaxis reduces systemic inflammation in HIV infection through a combination of altering specific gut bacterial populations and directly dampening immune activation, rather than through broad microbiome restructuring. Targeting streptococcal populations and intestinal inflammation, alongside direct anti-inflammatory drug effects, may be a mechanism underlying reduced HIV-related mortality and morbidity. This dual mechanism could inform strategies to further optimize prophylactic approaches in HIV-positive populations on antiretroviral therapy.