Antibiotic Resistance Genes Found in Newborns' Gut Microbiomes
Antibiotic resistance genes (ARGs) were detected in the gut microbiomes of newborns within the first 72 hours of life, suggesting a pattern of resistance is established very early.
New research presented at the European Society of Clinical Microbiology and Infectious Diseases Global 2026 conference analyzed stool samples from 105 infants admitted to a neonatal intensive care unit. The study found that these newborns harbored antibiotic resistance genes (ARGs)—segments of DNA that enable bacteria to survive antibiotic treatments—in their developing gut microbiomes.
The genes detected were associated with resistance to commonly used antibiotics, including those that can break down widely prescribed medications.
Key Findings
Lead author Dr. Argyro Ftergioti stated that the findings indicate a pattern of ARGs is established very early in life. The neonatal gut was described as harboring a diverse resistome, with the presence of clinically important ARGs at this stage noted as concerning.
Connections were identified between the presence of these resistance genes and several maternal and neonatal factors:
- Maternal hospitalization during pregnancy.
- Central venous catheter placement in the infant within the first 24 hours of life.
The collection of antibiotic resistance genes before birth appears to be shaped by a combination of maternal transmission, delivery methods, and early hospital exposures. Dr. Ftergioti noted that while some ARGs were expected, their high prevalence across the majority of samples was striking.
Context and Implications
The gut microbiome in newborns plays a crucial role in developing the immune, digestive, and nervous systems. A healthy microbiome is necessary for protection against infections, allergies, and future chronic diseases such as asthma, ADHD, and diabetes.
Further research is needed to understand how early carriage of resistance genes affects microbiome development and infection risk.
Earlier studies have found that newborns have more gut bacteria than previously thought, containing approximately 10,000 viral species. The new findings highlight the importance of surveillance, infection prevention, and control in neonatal care.