Related Experiment Video
Updated: Mar 12, 2026
Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae
Published on: January 17, 2014
Longitudinal investigation of nasopharyngeal methicillin-resistant Staphylococcus aureus colonization in early
Insights
Staphylococcus aureus colonization, including MRSA, is common in infants. Persistent MRSA strains in infant-mother pairs suggest household spread is a key factor in early infant colonization.
Area of Science:
- Microbiology
- Public Health
- Pediatrics
Background:
- Staphylococcus aureus colonization is prevalent in infants.
- Understanding long-term colonization patterns and strain relatedness is crucial for public health interventions.
- The association between maternal and infant colonization requires further investigation.
Purpose of the Study:
- To determine long-term Staphylococcus aureus colonization patterns in infants.
- To analyze strain relatedness among colonized infants and mothers.
- To investigate the association between maternal and infant Staphylococcus aureus colonization.
Main Methods:
- A birth cohort study was conducted from January 2012 to November 2014.
- Nasopharyngeal swabs were collected from infants at 1, 2, 4, 6, and 12 months.
- Maternal swabs were collected when infants were 1 month old.
Main Results:
- Staphylococcus aureus prevalence decreased from 61.0% at 1 month to 12.2% at 12 months.
- Persistent colonization (≥4/5 visits) was found in 13.8% of carriers, mostly with methicillin-resistant S. aureus (MRSA).
- Maternal MRSA colonization was linked to infant colonization, with related genotypes suggesting household transmission.
Conclusions:
- Staphylococcus aureus and MRSA colonization are common in infants.
- Persistent MRSA strains in infant-mother pairs often share indistinguishable genotypes.
- Horizontal spread within households is a significant factor in infant MRSA colonization.
Objectives:
The study aimed to determine the long-term Staphylococcus aureus colonization patterns and strain relatedness, and the association between maternal and infant colonization in infancy.
Methods:
A birth cohort study was conducted from January 2012 to November 2014. Nasopharyngeal swabs for S. aureus detection were collected from infants at the age of 1, 2, 4, 6 and 12 months and from mothers when their children were 1-month-old.
Results:
In total, 254 samples were collected at each planned visit during the first 12-month study. The prevalence of S. aureus colonization decreased in the first year of life, ranging from 61.0% (155/254) at the age of 1 month to 12.2% (31/254) at 12 months. Persistent colonization, defined as a positive culture on four or five occasions, was detected in only 13.8% (35/254) of carriers. Most of the persistent carriers were colonized with methicillin-resistant S. aureus (MRSA) only, and among persistent MRSA carriers, 61.1% (11/18) had indistinguishable genotypes. Of the mothers with MRSA colonization, 77.1% (27/35) had infants who were concomitantly colonized at the age of 1 month; 70.4% (19/27) of the infant-mother paired isolates belonged to indistinguishable or related subtypes, which suggests that surrounding carriers, probably their mothers, may be the possible source for MRSA acquisition in early infancy.
Conclusions:
Staphylococcus aureus colonization including MRSA was commonly observed in our cohort. Strains of persistent MRSA among infant-mother pairs were usually of indistinguishable genotypes. Therefore, horizontal spread within households is possibly an important factor related to infant MRSA colonization.
