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Updated: May 20, 2026
Assessment of Intestinal Transcytosis of Neonatal Escherichia coli Bacteremia Isolates
Published on: February 17, 2023
Screening fecal enterococci from Greek healthy infants for susceptibility to antimicrobial agents
Ekaterini I Kirtzalidou1, Evdokia K Mitsou, Paraskevi Pramateftaki
1Department of Nutrition and Dietetics, Harokopio University, Kallithea, Greece.
Insights
Antibiotic-resistant enterococci colonize healthy neonates early. This study found high rates of resistance to rifampicin, tetracycline, erythromycin, and vancomycin in infant gut bacteria, highlighting a significant public health concern.
Area of Science:
- Microbiology
- Neonatal Health
- Antimicrobial Resistance
Background:
- Enterococci are early colonizers of the neonatal gut and potential nosocomial pathogens.
- Understanding early antibiotic resistance in neonates is crucial for public health.
Purpose of the Study:
- To investigate the incidence of antibiotic resistance in enterococci from neonatal gut microbiota.
- To identify genetic determinants of antibiotic resistance in these isolates.
Main Methods:
- Analysis of 263 fecal samples from 97 infants at 4, 30, and 90 days postpartum.
- Phenotypic testing for resistance to 12 antibiotics.
- Molecular detection of specific antibiotic resistance genes (e.g., ermB, tet genes, vanC genes).
Main Results:
- Enterococcus faecalis and E. faecium were the most common species.
- High prevalence of resistance observed: rifampicin (53.2%), tetracycline (42.0%), erythromycin (35.7%), and vancomycin (11.2%).
- Multiresistant strains were common; intrinsic vancomycin resistance genes (vanC1, vanC2/C3) were detected, along with ermB and tet genes.
Conclusions:
- Antibiotic-resistant enterococci are prevalent in the gut microbiota of healthy neonates from early life.
- Early colonization by resistant strains poses a potential risk for future infections and public health.
- The presence of resistance genes highlights the need for surveillance and infection control strategies.
Abstract:
Enterococci are among the first lactic acid bacteria to colonize the neonatal gastrointestinal tract, but they are also characterized as significant nosocomial pathogens. The aim of this study was to investigate the incidence of antibiotic resistance in enterococci isolated from neonates' gut microbiota as well as the presence of genetic determinants encoding for certain antibiotic resistance traits. A total of 263 fecal samples derived from 97 infants were collected on day 4, 30, and 90 after delivery. Enterococcus faecalis was the most frequently identified species (54.6%) followed by E. faecium, while E. casseliflavus/E. flavescens and E. gallinarum were also traced. The isolates were examined for their resistance to 12 antibiotics. Rifampicin resistance was the highest observed (53.2%), followed by resistance to tetracycline (42.0%), erythromycin (35.7%), and vancomycin (11.2%). Multiresistant strains were highly prevalent. Only intrinsic vancomycin resistance (vanC1 and vanC2/C3) was traced. The ermB gene was detected in 49 out of 96 erythromycin-resistant isolates, while tet genes were detected in 51 out of 113 tetracycline-resistant strains, with tet(L) being the most frequently observed. In conclusion, antibiotic-resistant enterococci are already established in the fecal microbiota of healthy neonates, from the first days of an infant's life.
