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Antibiotic resistance in Staphylococcus aureus colonising the intestines of Swedish infants

E Lindberg1, I Adlerberth, A E Wold

  • 1Department of Clinical Bacteriology, Göteborg University, Göteborg, Sweden. erika.lindberg@microbio.gu.se

Clinical Microbiology and Infection : the Official Publication of the European Society of Clinical Microbiology and Infectious Diseases
|September 18, 2004
PubMed

Insights

Antibiotic-resistant Staphylococcus aureus strains colonize infant intestines. These resistant strains persist and thrive as well as susceptible ones, potentially worsening antibiotic resistance issues.

Area of Science:

  • Microbiology
  • Pediatric Health
  • Infectious Diseases

Background:

  • Staphylococcus aureus frequently colonizes the infant intestinal tract, but health implications remain unclear.
  • Understanding the behavior of antibiotic-resistant strains in this commensal microflora is crucial.

Purpose of the Study:

  • To determine the antibiotic resistance patterns of Staphylococcus aureus strains colonizing the infant gut.
  • To assess the relationship between antibiotic resistance, infant antibiotic consumption, and strain persistence.
  • To evaluate the fitness of antibiotic-resistant S. aureus in the infant intestinal microflora.

Main Methods:

  • Analysis of 116 S. aureus strains from fecal samples of 81 Swedish infants.
  • Determination of antibiotic resistance patterns (methicillin, penicillin G, erythromycin A, tetracycline, clindamycin, fusidic acid).
  • Correlation of resistance with infant antibiotic usage, strain fecal population levels, and persistence.

Main Results:

  • Prevalence of resistance was modest: Penicillin G (78%), Erythromycin A (3%), Tetracycline (2%), Clindamycin (0.9%), Fusidic Acid (0.9%). Methicillin resistance was 0%.
  • Antibiotic resistance was not linked to infant antibiotic consumption.
  • Resistant S. aureus strains demonstrated similar persistence and high fecal population levels as susceptible strains.
  • No resistance loss or acquisition was observed during colonization.

Conclusions:

  • Antibiotic-resistant S. aureus strains are as ecologically fit as susceptible strains in the infant gut microflora, even without antibiotic selective pressure.
  • The persistence of these resistant strains may exacerbate the broader ecological consequences of antibiotic resistance development.
  • Findings highlight the need to monitor S. aureus colonization in infants and its implications for antibiotic resistance.

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