Researchers tested whether probiotics (helpful bacteria) could boost the effectiveness of a drug called miltefosine against leishmaniasis, a tropical disease that causes skin sores. Using mice infected with the parasite, they found that a specific probiotic blend called PB8, when combined with the medicine, reduced skin lesions by 74% compared to untreated mice. The medicine alone only reduced lesions by 53%. The probiotics appeared to work by calming down the body’s inflammatory response, which can sometimes make the disease worse. This early research suggests probiotics might be a useful addition to current treatments, though human studies are still needed.

The Quick Take

  • What they studied: Whether adding probiotics (good bacteria) to an existing leishmaniasis drug could work better than the drug alone at treating skin sores caused by a tropical parasite
  • Who participated: Laboratory mice (BALB/c strain) that were infected with Leishmania amazonensis, a parasite that causes cutaneous leishmaniasis (skin disease). The study did not involve human participants.
  • Key finding: When a probiotic blend called PB8 was combined with a lower dose of miltefosine drug, it reduced skin lesions by 74%, compared to only 53% reduction with the drug alone. The combination also reduced the number of parasites in the skin by 76-87%.
  • What it means for you: This research suggests that probiotics might help make existing leishmaniasis treatments more effective and allow doctors to use lower drug doses. However, this is early-stage research in mice, and human studies are needed before this approach could be used in patients. If you have leishmaniasis, talk to your doctor before adding probiotics to your treatment.

The Research Details

This was a laboratory experiment using mice to test whether probiotics could improve treatment of a parasitic skin disease. Researchers gave mice probiotics for 7 days before infecting them with the parasite, then continued the probiotics for 14 more days while also giving them the drug miltefosine. They measured how much the skin sores shrank and counted how many parasites remained in the skin using two methods: looking at samples under a microscope and using a genetic test called qPCR. They also checked blood samples to see how the probiotics affected the mice’s immune system by measuring different immune chemicals called cytokines.

The researchers tested two types of probiotics: a multi-strain blend called PB8 (containing multiple types of helpful bacteria) and a single-strain probiotic called Lactobacillus rhamnosus GG (LGG). They compared results between mice that got probiotics alone, the drug alone, probiotics plus the drug, and untreated control mice.

The study was designed to explore whether the gut bacteria from probiotics could help the body’s immune system fight the parasite more effectively, since previous research has shown that gut bacteria play an important role in how our immune system works.

This research approach matters because current treatments for leishmaniasis are old, can cause serious side effects, and the parasite is becoming resistant to them. By testing whether probiotics can boost the immune system to help fight the infection, researchers are exploring a potentially safer way to improve treatment. Using animal models first allows scientists to understand how a treatment works before testing it in humans, which is an important safety step.

This study was conducted by researchers at a respected Brazilian research institute (Instituto Oswaldo Cruz) that specializes in tropical diseases. The researchers used multiple methods to measure results (visual measurement, microscopy, and genetic testing), which strengthens their findings. However, this is animal research only—results in mice don’t always translate to humans. The study size and specific number of mice used were not clearly stated in the abstract. Because this is early-stage research, the findings should be considered preliminary and need confirmation through human clinical trials before being used in medical practice.

What the Results Show

The main finding was that combining the PB8 probiotic blend with a lower dose of miltefosine (4 mg/kg/day) was significantly more effective than using the drug alone. The combination reduced skin lesion size by 74% compared to untreated mice, while the drug alone achieved only 53% reduction. This means the probiotics appeared to make the drug work better, potentially allowing doctors to use lower, safer doses.

When researchers counted the actual parasites in the skin using two different methods, the results were even more impressive. The PB8 plus miltefosine combination reduced parasite numbers by 76% (using microscopy) and 87% (using genetic testing), compared to untreated mice. This suggests the combination was very effective at killing the parasites.

Interestingly, probiotics alone (without the drug) did provide some benefit. The PB8 probiotic by itself reduced lesion size by 32%, while the single-strain LGG probiotic reduced it by only 10%. This suggests that the multi-strain probiotic blend was more effective than a single strain, though neither worked as well as the combination with the drug.

The researchers also found that the PB8 probiotic appeared to reduce inflammation by lowering a chemical in the blood called CCL2. This is important because high levels of CCL2 can actually make leishmaniasis worse by attracting too many immune cells to the infection site, causing excessive inflammation.

The immune system analysis revealed that probiotics modified how the body’s immune chemicals (cytokines) responded to infection. Specifically, the PB8 probiotic reduced levels of CCL2, a chemical messenger that recruits immune cells. While some immune response is necessary to fight infection, too much can cause tissue damage and make the disease worse. By reducing CCL2, the probiotics appeared to help balance the immune response—strong enough to fight the parasite but not so strong as to cause excessive inflammation.

This research builds on earlier findings showing that gut bacteria influence how well the immune system works. Previous studies have suggested that probiotics can help with various infections by boosting immune function. This study is novel because it specifically tests whether probiotics can enhance the effectiveness of an existing leishmaniasis drug. The finding that probiotics allow a lower drug dose to work better is particularly important because it could reduce side effects from the medication.

This study has several important limitations. First, it was conducted only in mice, not humans, so the results may not work the same way in people. Second, the abstract doesn’t specify exactly how many mice were used in each group, making it difficult to assess the statistical strength of the findings. Third, the study only tested one drug (miltefosine) and two probiotic products, so results may not apply to other leishmaniasis treatments or other probiotic brands. Fourth, this was a short-term study (47-50 days), so we don’t know if the benefits would last longer or if any long-term side effects might develop. Finally, the study didn’t test whether the probiotics would work in people with weakened immune systems or other health conditions that might affect results.

The Bottom Line

Based on this early research, probiotics show promise as a potential addition to leishmaniasis treatment, but the evidence is still preliminary. Current recommendation level: This is laboratory research only and should not yet be used as a basis for changing medical treatment. Healthcare providers should wait for human clinical trials before considering probiotics as part of leishmaniasis therapy. If you have leishmaniasis, continue following your doctor’s prescribed treatment plan.

This research is most relevant to: (1) Researchers studying leishmaniasis and tropical diseases, (2) Pharmaceutical companies developing new treatments, (3) Public health organizations in countries where leishmaniasis is common, and (4) Patients with leishmaniasis who might eventually benefit from improved treatments. This research should NOT yet be used by patients to self-treat leishmaniasis with probiotics instead of prescribed medications. People living in areas where leishmaniasis is common should continue using proven prevention methods like insect repellent and bed nets.

In this mouse study, benefits appeared within 47-50 days of treatment. However, if this approach moves to human trials, it could take several years to determine if similar benefits occur in people and at what doses. Realistic timeline for potential human use: 5-10 years of additional research and clinical trials would likely be needed before this could become a standard treatment option.

Want to Apply This Research?

  • For users with leishmaniasis receiving treatment: Track lesion size weekly using a ruler or measuring tape (measure the longest dimension of the sore), photograph the lesion under consistent lighting, and record any changes in skin appearance, itching, or pain on a scale of 1-10. Note any side effects from medications.
  • If future research confirms these findings in humans, users could work with their healthcare provider to: (1) Take a prescribed probiotic supplement alongside their leishmaniasis medication as directed, (2) Maintain a food diary noting probiotic-rich foods like yogurt or kefir, and (3) Track medication adherence to ensure consistent treatment.
  • Long-term tracking should include: Weekly lesion measurements and photos, monthly immune system markers if available through healthcare provider, ongoing symptom severity ratings, medication side effect documentation, and regular check-ins with healthcare provider to assess treatment effectiveness and adjust if needed.

This research is preliminary laboratory work conducted in mice and has not been tested in humans. Do not use probiotics as a substitute for prescribed leishmaniasis treatment. If you have leishmaniasis or suspect you may have it, consult with a healthcare provider for proper diagnosis and treatment. Always follow your doctor’s treatment recommendations. This article is for educational purposes only and should not be considered medical advice. Future human clinical trials are needed before any of these findings can be applied to patient care.