Why Hospitals Treat the Same Infection in Very Premature Babies for Different Lengths of Time

What an international survey of 382 neonatal units by Seliga-Siwecka and colleagues reveals about antibiotics, IV lines and blood tests for babies born before 29 weeks

When a very premature baby develops a blood infection, doctors around the world agree that antibiotics are needed, but they do not agree on how long to give them. A survey of 382 neonatal intensive care units in 12 neonatal networks found that the usual course ranged from under a week to three weeks or more, depending on the germ and on the hospital. The survey describes what units say they do; it does not show which approach is best, and researchers are now working to find out.

Why This Question Matters to Families

Babies born more than 11 weeks early, before 29 weeks of pregnancy, spend many weeks in a neonatal intensive care unit (NICU). Their immune systems are immature, and many of them need a central line, a thin tube placed in a large vein to give nutrition and medicines. Infections are one of the most serious risks of this period. If your baby has had a "positive blood culture" (a blood test that grew germs in the laboratory), you may have been told how many days of antibiotics are planned. It is natural to wonder why that number was chosen. This article explains what a large international study, published in 2026 by Dr Joanna Seliga-Siwecka and colleagues, found when it asked hospitals that very question [1].

What Doctors Have Long Been Balancing

For many years, NICU teams have walked a careful line between two risks. The first is the infection itself. In a large group of United States hospitals, about 9 in every 100 very premature babies developed an infection after their first few days of life, and the risk was highest in the smallest babies: about one in three of those born at 23 weeks or earlier [2]. An older study of more than 6000 babies born weighing 1 kilogram or less found that those who had infections were more likely to have later problems with development and with head growth [3]. This is why doctors start antibiotics quickly when they suspect infection.

The second risk is too much antibiotic. Experts have described how fear of missing an infection leads to babies receiving more antibiotics than they need, which can upset the healthy bacteria developing in a baby's gut and encourage germs that resist antibiotics [4]. Antibiotic-resistant germs are a worldwide problem, estimated to have directly caused 1.27 million deaths across all ages in 2019 [5]. Hospitals have responded with "antibiotic stewardship", meaning careful programmes to use antibiotics only when and for as long as they are needed. One such programme, the SCOUT study at a single NICU at Parkland Hospital in Dallas, Texas, cut antibiotic use by about a quarter without making babies less safe, mostly by stopping antibiotics early when tests showed no infection [6]. Across hundreds of American NICUs, the number of antibiotic days for the tiniest babies, counted per 1000 days spent in hospital, fell by more than a third between 2009 and 2021 (from 337 to 210), even though nearly 9 in 10 of them still receive antibiotics at some point [7].

When an infection is confirmed, though, the picture has been less clear. Traditionally, confirmed blood infections were treated for 10 to 14 days [1]. Small studies suggested shorter courses might work just as well, but they were done in India in larger, more mature babies, and the experts reviewing them rated the evidence as very uncertain [8]. For meningitis, an infection of the lining around the brain and spinal cord, recommended treatment lengths have rested mostly on expert opinion rather than on studies [9]. An earlier worldwide one-day survey, the No-More-Antibiotics and Resistance (NO-MAS-R) study in 84 NICUs across 29 countries, found that confirmed infections were usually treated for around 12 days [10], but fewer than 1 in 4 of the babies it counted had been born extremely early [1]. Those earlier studies had not looked, germ by germ, at how hospitals treat the most premature babies [1].

How the Study Was Done

Dr Seliga-Siwecka's team, working with the International Network for Evaluating Outcomes of Neonates (iNeo), a research partnership of national and regional neonatal networks, sent an online questionnaire to 608 NICUs between July 2023 and March 2024 [1]. The networks covered Australia and New Zealand together, Brazil, Canada, Finland, France, Israel, Japan, Poland, Spain, Sweden, Switzerland and the Tuscany region of Italy. One person in each unit answered on its behalf, after talking with colleagues. Of the 608 units, 382 replied, or about 63 in every 100.

The questions covered four topics for babies born before 29 weeks: how long antibiotics or antifungal medicines are usually given for a confirmed infection, whether medicine is given to prevent fungal infection, how many blood samples are taken for a culture, and whether the central line is removed when an infection is found. It is important to understand what kind of study this is. It is a survey of what hospitals say they usually do. It did not follow individual babies, and it did not compare how babies fared under different approaches.

What the Hospitals Reported

Doctors group bacteria into two broad families, called Gram-positive and Gram-negative, after a laboratory stain. For Gram-positive blood infections, the most common answer was 7 days, given by about 45 in every 100 units [1]. For Gram-negative infections, the most common answer was 14 days, given by about 44 in every 100 units, although about 1 in 5 units used 7 days. The differences between countries were striking. In Japan, most units reported 14 days even for Gram-positive infections, while in Australia and New Zealand nearly 3 in every 10 units reported less than 7 days.

When the infection had also reached the brain lining, courses were longer. Most units treated Gram-positive meningitis for 14 days and Gram-negative meningitis for 21 days, the second being the area where hospitals agreed most. For fungal infections in the blood, half of units gave 14 days of treatment, and for fungal meningitis more than half treated for longer than three weeks.

The other practices varied too. About 8 in every 10 units usually took a blood culture from just one site, but in Israel most units routinely took two. When a baby with a central line developed a Gram-negative infection, about three-quarters of units said they would remove the line; for Gram-positive infections, the figure was just over half, ranging from 1 in 10 units in Brazil to about 9 in 10 in Japan. Finally, about 6 in every 10 units gave some babies medicine to prevent fungal infections, usually only to those with particular risk factors, while most units in Brazil, Canada and Switzerland did not use it, and nearly half of Spanish units did not either [1].

Why Hospitals Might Make Different Choices

There are understandable reasons behind some of these differences. An American guideline on infected IV lines advises removing the line for certain germs but allows doctors to try keeping it for some common skin germs, so the decision can depend on exactly which germ is found and when [11]. An earlier Canadian survey had also found that more than half of units process a single blood culture bottle when infection is suspected later in a baby's stay, and that there are no agreed guidelines for how blood cultures should be collected in newborns [12]. And the evidence on preventing fungal infection shows that the medicine lowers the number of fungal infections in settings where they are common, but without a clear effect on survival [13]. The survey's authors suggest that hospitals differ partly because their babies' risk of fungal infection differs.

What the Survey Cannot Tell Us

The researchers are open about the study's limits. Answers describe usual practice, not what actually happened to each baby. Fewer than 4 in 10 Japanese units replied, and Japan was the largest group invited, so the results may not reflect every hospital. Some networks are very small (Tuscany had only 4 units), so a single unit can change their percentages a lot. Most importantly, the survey cannot say whether shorter or longer courses lead to better results for babies [1].

What Researchers Are Working on Next

Since the survey closed, new evidence has appeared. A study across eight hospitals in India, in babies weighing at least 1 kilogram, found that stopping antibiotics after 7 days rather than 14 days for uncomplicated blood infections did not appear to increase the chance of the infection coming back [14]. A combined analysis of many studies reached a similar conclusion for blood infections, but could not answer the question for meningitis or fungal infections [15]. You can read more about that research at https://inneosight.org/en-US/articles/antibiotic-duration-neonatal-infections-nima2025. Most of these babies were bigger and more mature than those in the iNeo survey, so studies in the very smallest babies are still needed. The iNeo researchers hope their map of current practice will help design those studies.

What This Means for You and Your Baby

If your baby is being treated for an infection, the length of the course your team has chosen is likely to be within the range used by many respected hospitals around the world. Different does not mean wrong: it reflects the honest fact that the ideal length has not yet been proven for the smallest babies. It is always reasonable to ask your baby's doctors which germ was found, how long treatment is planned, why, and whether the central line will stay in. Good teams welcome these questions. This survey shows how much doctors still need to learn together, and it is a step towards giving every premature baby treatment that is long enough to cure the infection, but no longer than it needs to be.

References

  1. Seliga-Siwecka J, Romańska J, Lui K, et al. International Variations in the Use of Antimicrobials and Management of Sepsis: A Survey of 382 Neonatal Units in 12 Countries. Neonatology. 2026:1. doi:10.1159/neo/adsag014 ↩
  2. Flannery DD, Edwards EM, Coggins SA, Horbar JD, Puopolo KM. Late-Onset Sepsis Among Very Preterm Infants. Pediatrics. 2022;150(6):e2022058813. doi:10.1542/peds.2022-058813 ↩
  3. Stoll BJ, Hansen NI, Adams-Chapman I, et al. Neurodevelopmental and growth impairment among extremely low-birth-weight infants with neonatal infection. JAMA. 2004;292(19):2357-2365. doi:10.1001/jama.292.19.2357 ↩
  4. Stocker M, Klingenberg C, Navér L, et al. Less is more: Antibiotics at the beginning of life. Nat Commun. 2023;14(1):2423. doi:10.1038/s41467-023-38156-7 ↩
  5. Antimicrobial Resistance Collaborators. Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis. Lancet. 2022;399(10325):629-655. doi:10.1016/S0140-6736(21)02724-002724-0) ↩
  6. Cantey JB, Wozniak PS, Pruszynski JE, Sánchez PJ. Reducing unnecessary antibiotic use in the neonatal intensive care unit (SCOUT): a prospective interrupted time-series study. Lancet Infect Dis. 2016;16(10):1178-1184. doi:10.1016/S1473-3099(16)30205-530205-5) ↩
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  9. Van Hentenryck M, Schroeder AR, McCulloh RJ, Stave CD, Wang ME. Duration of Antibiotic Therapy for Bacterial Meningitis in Young Infants: A Systematic Review. Pediatrics. 2022;150(5):e2022057510. doi:10.1542/peds.2022-057510 ↩
  10. Prusakov P, Goff DA, Wozniak PS, et al. A global point prevalence survey of antimicrobial use in neonatal intensive care units: The no-more-antibiotics and resistance (NO-MAS-R) study. EClinicalMedicine. 2021;32:100727. doi:10.1016/j.eclinm.2021.100727 ↩
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  13. Cleminson J, Austin N, McGuire W. Prophylactic systemic antifungal agents to prevent mortality and morbidity in very low birth weight infants. Cochrane Database Syst Rev. 2015;2015(10):CD003850. doi:10.1002/14651858.CD003850.pub5 ↩
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