Around the world, more bacterial infections are growing resistant to standard antibiotics, making them harder to treat. Antimicrobial resistance is especially dangerous for critically ill newborns, infants and young children, whose small bodies can be overwhelmed quickly by infection.
When other antibiotics fail, doctors sometimes turn to colistin, an older drug that has regained importance for multidrug-resistant infections, especially in resource-constrained settings. But while colistin has long been used in adults, little is known about the right dose for babies and children under two. Without good evidence, there is a risk of giving too little, which may lead to inadequate treatment and potentially contribute to further antibiotic resistance, or too much, which may increase the risk of side effects.
This is the gap the PRECISION study aims to close. This observational pharmacokinetic study, part of the Penta-led SNIP-AFRICA project, is examining how colistin behaves in the bodies of newborns infants and children under two. It is currently underway at Tygerberg Hospital in Cape Town, with a second site opening soon at Chris Hani Baragwanath Academic Hospital in Johannesburg.
On the occasion of World Sepsis Day 2026, we spoke with the Stellenbosch University team leading PRECISION about their research and its potential impact.
- Why can’t doctors simply use the same dosing information that’s available for adults?
A child’s body is not a smaller version of an adult. As children grow and develop, the way their bodies handle medicines changes. Their organs, and especially the kidneys, which play an important role in the handling of many medicines including colistin, are still maturing, and that changes how the drug behaves.
Babies also grow fast: they double their birth weight by 6 months and triple it by 12 months, so a dose that’s right one month may be wrong the next. Severe infection and sepsis add yet another layer of unpredictability, since illness itself can alter how a critically ill child’s body processes a drug.
There is already evidence that simply applying adult or older-child doses to younger children may not give them enough colistin. Current recommendations on colistin advise dosing according to body weight without considering younger children’s organ maturity, and studies have reported lower colistin concentrations in children receiving such doses. Almost no research has really looked at this in children under two: until now, only one small study had specifically assessed colistin concentrations in newborns.
- What is the PRECISION study actually measuring?
We are trying to answer a very practical question: after a child receives colistin, what happens to the medication inside their body?
We take a small number of carefully timed blood samples after a dose and measure the concentration of colistin in the blood over time. From that, we can determine how the medication is distributed through the body, its highest and lowest levels, and how quickly it leaves their body.
The team also gathers information about the infection itself: which bacteria are involved and how susceptible they are to colistin, to confirm that colistin is actually the right drug against those bacteria.
The aim is to replace estimates with real evidence from the patients who actually need it, so that dosing decisions for younger children rest on solid data, not extrapolation.
- Is it safe for babies to take part? What should parents know?
Yes. PRECISION is an observational study, meaning no child is given colistin for research purposes. A child only joins if their own doctors have already prescribed colistin as part of their normal care. Researchers simply observe and measure, they don’t change the treatment. Because these are very young and vulnerable patients, the study has strict safeguards:
- A parent or legal guardian must give informed consent, after having every question answered by the research team. Participation in the study is also entirely voluntary.
- Only a small amount of blood is collected. Each blood sample for PRECISION is only 0.5 mL, or one-tenth of a teaspoon, with a maximum of three samples per baby.
- Children keep getting their normal medical care and monitoring throughout.
- Records use participant numbers to protect the identity of the children participating in the study.
- How could this change policy and practice around sepsis treatment?
The findings would give doctors evidence-based guidance on the safest and most effective way to use colistin in newborns, infants and very young children, which is critical information for treating serious infections when other antibiotics have failed. This matters most in places like South Africa, where newer antibiotics for highly resistant infections aren’t always available and colistin may be one of the few remaining options. Getting the dose right means treating infections effectively while minimising the risk of harm.
The impact could extend well beyond the children who take part in this study. The findings could help improve recommendations for treating young children in South Africa and Southeast Asia, and potentially contribute to treatment guidelines in other countries as well.
In the photo: the PRECISION study team. From left to right: Eric Decloedt, Adrie Bekker, Veshni Pillay-Fuentes Lorente, Roland van Rensburg; Stellenbosch University, South Africa.