Identification and control of an outbreak of ciprofloxacin-susceptible EMRSA-15 on a neonatal unit

Area of Science:

• Medical Microbiology
• Infectious Disease Epidemiology
• Neonatal Care

Background:

• Meticillin-resistant Staphylococcus aureus (MRSA) outbreaks pose significant risks in neonatal units.
• Standard screening methods may not detect all circulating MRSA strains, particularly those with altered susceptibility patterns.

Purpose of the Study:

• To identify and control an outbreak of a specific MRSA strain on a neonatal unit.
• To evaluate the effectiveness of standard screening protocols and implement targeted control measures.

Main Methods:

• Screening of neonates on admission using ciprofloxacin-containing media.
• Identification of MRSA isolates, including molecular typing (spa type, SCCmec type) and antimicrobial susceptibility testing.
• Environmental screening and investigation of potential transmission routes.
• Implementation of infection control measures including cohort isolation, enhanced cleaning, and hand hygiene.

Main Results:

• An outbreak of ciprofloxacin-susceptible EMRSA-15 (ST30, SCCmec IV, PVL-negative) was identified.
• Initial screening with ciprofloxacin-containing media failed to detect the outbreak strain.
• The strain was found in four neonates (one with invasive disease) and environmental samples.
• Control measures successfully contained the outbreak.

Conclusions:

• Ciprofloxacin-containing media may fail to detect ciprofloxacin-susceptible MRSA strains, necessitating careful consideration in screening protocols.
• Enhanced infection control practices, including environmental hygiene and maternal education, are crucial for managing MRSA outbreaks in neonatal settings.
• The unsupervised movement of mothers in communal areas may have facilitated transmission.