Measurement and Impact of Staphylococcus aureus Colonization Pressure in Households

Area of Science:

• Infectious Diseases
• Epidemiology
• Microbiology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) colonization pressure (CP) is a known predictor of hospital-acquired infections.
• The study investigated the applicability of the CP concept to Staphylococcus aureus transmission within household settings.
• The research focused on children with skin and soft tissue infections (SSTIs) and S. aureus colonization.

Purpose of the Study:

• To test the hypothesis that higher baseline household CP (HHCP) increases the risk of persistent S. aureus colonization and recurrent SSTIs in pediatric cases.
• To evaluate the association between HHCP and the persistence of S. aureus colonization in children.
• To determine if HHCP influences the recurrence of SSTIs in pediatric patients.

Main Methods:

• Baseline colonization swabs were collected from 92 pediatric cases and 296 household contacts.
• Household S. aureus CP (HHCP) was calculated as the proportion of colonized household contacts at baseline.
• Cases underwent decolonization, and colonization and recurrent SSTIs were monitored for 12 months.

Main Results:

• A median S. aureus HHCP of 60% was observed across all households.
• For MRSA-colonized cases, the median MRSA HHCP was 11%, while MSSA-colonized cases had a median MSSA HHCP of 50%.
• Higher MRSA HHCP independently predicted persistent MRSA colonization in cases over 12 months (aOR=1.25 per 10-unit increase), but HHCP was not linked to recurrent SSTIs.

Conclusions:

• Household MRSA CP is a significant factor associated with persistent MRSA colonization in outpatient settings.
• Further research is warranted to elucidate the interplay between household contact colonization, environmental contamination, and SSTI development.
• The findings highlight the importance of household transmission dynamics in managing S. aureus infections.