Staphylococcus aureus in a neonatal care center: methicillin-susceptible strains should be a main concern

Area of Science:

• Neonatal care epidemiology
• Infectious disease surveillance
• Bacterial outbreak investigation

Background:

• Investigated Staphylococcus aureus (SA) epidemiology in a neonatal care center (NCC) during a methicillin-susceptible SA (MSSA) outbreak.
• Aims to enhance understanding of SA dynamics in a tertiary care teaching hospital setting.

Purpose of the Study:

• To analyze the epidemiology of SA, including intestinal carriage, colonization, and infection, over one year.
• To characterize the MSSA outbreak strains and assess contributing factors to its emergence.

Main Methods:

• Conducted a comprehensive one-year review of SA patient data.
• Calculated monthly prevalence and incidence of SA carriage, colonization, and infection.
• Analyzed MSSA strains for antimicrobial resistance, virulence genes, and by Pulsed-Field Gel Electrophoresis; audited infection control practices and investigated environmental reservoirs.

Main Results:

• Observed 2-3 prevalence peaks of SA on a background of endemicity, with MSSA prevalence consistently above 5.5% and MRSA around 1.53% in the NCC during 2009.
• The MSSA outbreak correlated with increased catheter-related infections, likely due to relaxed infection control and high colonization pressure.
• Healthcare workers' white coats identified as a potential environmental reservoir for SA circulation.

Conclusions:

• Highlights the critical need to integrate MSSA surveillance with methicillin-resistant SA (MRSA) monitoring in NCCs.
• Emphasizes the importance of robust infection control practices to manage SA epidemiology in vulnerable neonatal populations.