A case report describes successfully treating a newborn's carbapenem-resistant bacterial pneumonia with a three-drug combination including colistin (polymyxin), tigecycline, and aztreonam — with the infant recovering and being discharged.
Successful recoveryA neonate with CRE pneumonia and renal impairment was treated with a triple antibiotic combination including colistin and discharged without significant adverse events
What the researchers found
The combination of aztreonam, colistin (polymyxin), and tigecycline successfully controlled a carbapenem-resistant Enterobacteriaceae (CRE) infection complicated by pneumonia and renal impairment in a neonate. The infant required invasive mechanical ventilation initially but showed improved respiratory function, managed spontaneous breathing, and was eventually discharged without significant adverse events.
The authors emphasize that combining peptide antibiotics (polymyxins) with other drug classes effective against resistant gram-negative bacteria can lower mortality in neonatal CRE pneumonia.
Why it matters
Carbapenem-resistant infections in newborns are life-threatening and extremely difficult to treat because these bacteria resist nearly all standard antibiotics. Colistin (polymyxin) is often called a 'last resort' antibiotic, but safety data in neonates is very limited. This case provides real-world evidence that colistin-based combination therapy can be both effective and tolerable in this vulnerable population — information desperately needed by NICU physicians facing these infections.
How the study worked
This is a single-patient retrospective case report analyzing clinical data from a neonate with CRE-related pneumonia and renal impairment treated in a NICU. The authors assessed clinical outcomes, respiratory status (including pulmonary ultrasound), and adverse events during treatment with the triple antibiotic combination.
What this study cannot tell us
This is a single case report — the lowest level of clinical evidence. Results from one patient cannot be generalized. The long-term effects of colistin and tigecycline exposure on neonatal development were not assessed. No control comparison was possible. The contribution of each individual antibiotic to the outcome cannot be determined from a combination regimen.
How to read the evidence
This is a single case report — the weakest form of clinical evidence. While it provides useful real-world data on a rarely studied population (neonates receiving colistin), no conclusions about efficacy or safety can be drawn from a single patient.
When this study was published
Published in 2026 in BMC Pediatrics. This is a very recent case report reflecting current clinical challenges with CRE infections in NICUs.
The bigger picture
Antimicrobial resistance is one of the biggest threats to global health, and neonates are among the most vulnerable patients. Polymyxins (colistin) — which are peptide antibiotics — have made a comeback as last-resort treatments despite their known toxicity risks. Every case report of safe, effective use in newborns adds valuable data to guide clinicians facing impossible treatment decisions with limited evidence.
Questions still open
- What are the long-term developmental outcomes for neonates exposed to colistin and tigecycline?
- Would a two-drug combination (without one of the three agents) have been equally effective?
- How should colistin dosing be optimized in neonates with renal impairment?
Common questions
What is colistin and why is it called a last-resort antibiotic?
Why are CRE infections so dangerous in newborns?
Read the original research
Combination of aztreonam, colistin and tigecycline in the treatment of neonatal carbapenemase-producing Enterobacteriaceae infection: a case report.
BMC pediatrics, 26(1)
Citation
Wang, Han; Tan, Yangyang. (2026). Combination of aztreonam, colistin and tigecycline in the treatment of neonatal carbapenemase-producing Enterobacteriaceae infection: a case report.. BMC pediatrics, 26(1). https://doi.org/10.1186/s12887-026-06511-4