Infants carry a diverse range of ARGs with peak prevalence observed at 6 and 14 wk, and delivery mode and maternal antibiotic exposure significantly impact ARG carriage during the first year of life.
Key Findings
Results
Infants predominantly carried antibiotic resistance genes conferring resistance to beta-lactams, macrolides, and sulphonamides during the first year of life.
Beta-lactam resistance genes were present in 80.6% of infants
Macrolide (MSLB) resistance genes were present in 70% of infants
Sulphonamide resistance genes were present in 61% of infants
Study examined the presence of 20 antibiotic-resistance genes in stool samples of 54 full-term healthy infants
Results
ARG carriage peaked at 6 weeks and 14 weeks of life, with significant increases in multiple specific resistance genes from birth to 6 weeks.
Genes showing significant increase from birth to 6 wk included blaTEM, catB, oqxA, sul1, ermB, tet, and blaSHV (P < 0.05)
McNemar's test was used to check the statistical significance of the change in prevalence of genes across various time points
Stool samples were collected at birth and at 6, 14, and 36 weeks
Results
Caesarean section delivery was significantly associated with increased carriage of the blaCTX-M gene at 6 weeks of life.
P = 0.001; odds ratio (OR): 6.93; confidence interval (CI): 2.06-23.26
Chi-square test and logistic regression were performed to evaluate the influence of clinical and demographic factors on ARG carriage
Results
Maternal exposure to cephalosporins postpartum was significantly associated with increased carriage of the blaCTX-M gene in infants at 6 weeks of life.
P = 0.013; OR: 4.16; CI: 1.31-13.17
This finding was independent of the delivery mode association also identified for blaCTX-M carriage
Methods
The study design involved longitudinal sampling of 54 full-term healthy infants at four time points during the first year of life.
54 full-term healthy infants were enrolled
Stool samples were collected at birth and at 6, 14, and 36 weeks
A panel of 20 antibiotic-resistance genes was examined
Both clinical and demographic factors were evaluated for their influence on ARG carriage
Mahesh S, Mutreja A, Shetty V, Kamath V, Aroor S, Madhav A, et al.. (2026). Temporal dynamics & determinants of antibiotic resistance gene profiles in the infant gut during the first year of life.. The Indian journal of medical research. https://doi.org/10.25259/IJMR_2096_2024