Mupirocin-resistant Staphylococcus aureus in a specialist school population

Area of Science:

• Microbiology
• Infectious Diseases
• Clinical Pharmacy

Background:

• Mupirocin is a topical antibiotic frequently used for skin infections, particularly in individuals with conditions like eczema, asthma, and cystic fibrosis.
• The emergence of antibiotic resistance is a significant global health concern, necessitating surveillance of resistance patterns for commonly used antimicrobials.

Purpose of the Study:

• To investigate the occurrence and characteristics of mupirocin-resistant Staphylococcus aureus strains in a school population.
• To determine the genetic basis and transmissibility of mupirocin resistance in recovered S. aureus isolates.

Main Methods:

• Bacterial isolates were collected from children and staff at a specialized school.
• Antimicrobial susceptibility testing, including minimum inhibitory concentration (MIC) determination for mupirocin, was performed.
• Plasmid analysis was conducted to identify the genetic mechanisms of resistance.

Main Results:

• Staphylococcus aureus strains exhibiting high-level mupirocin resistance (MIC > 4000 mg/L) were identified.
• At least three distinct S. aureus strains were implicated in the resistance.
• Transmissible plasmids were identified as the primary cause of mupirocin resistance in most isolates.

Conclusions:

• The study demonstrates the rapid emergence of high-level mupirocin resistance in S. aureus within a school environment after topical antibiotic application.
• Plasmid-mediated resistance poses a risk of further dissemination.
• Continuous monitoring of antibiotic use and resistance patterns is crucial to preserve the efficacy of valuable antimicrobial agents like mupirocin.