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Retapamulin Activity Against Pediatric Strains of Mupirocin-resistant Methicillin-resistant Staphylococcus aureus
Ami B Patel1, Jennifer Lighter1,2, Yi Fulmer3
1From the Department of Pediatrics, Division of Pediatric Infectious Diseases.
Abstract:
Retapamulin activity against 53 isolates obtained from a mupirocin-resistant community-acquired methicillin-resistant Staphylococcus aureus pediatric disease cluster was evaluated using broth microdilution. All strains were susceptible to retapamulin with minimum inhibitory concentrations ≤ 0.5 μg/mL. DNA sequence analysis of rplC and cfr identified one rplC strain variant that did not demonstrate reduced phenotypic susceptibility to retapamulin. These results demonstrate that retapamulin may be a useful alternative therapy for mupirocin-resistant community-acquired methicillin-resistant S. aureus, especially in disease clusters.
Insights
Retapamulin shows effectiveness against mupirocin-resistant community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) in pediatric cases. This finding suggests retapamulin as a potential alternative treatment for these challenging infections, particularly in outbreak settings.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Mupirocin resistance is a growing concern in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections.
- Pediatric disease clusters of CA-MRSA pose a significant public health challenge.
- Limited treatment options exist for mupirocin-resistant CA-MRSA.
Purpose of the Study:
- To evaluate the in vitro activity of retapamulin against mupirocin-resistant CA-MRSA isolates from a pediatric disease cluster.
- To investigate potential resistance mechanisms to retapamulin in these strains.
Main Methods:
- Broth microdilution was used to determine the minimum inhibitory concentrations (MICs) of retapamulin.
- DNA sequence analysis of the rplC and cfr genes was performed to identify resistance determinants.
Main Results:
- All 53 CA-MRSA isolates were susceptible to retapamulin, with MICs ≤ 0.5 μg/mL.
- One isolate with an rplC variant did not exhibit reduced susceptibility to retapamulin.
- No cfr-mediated resistance was observed.
Conclusions:
- Retapamulin demonstrates potent activity against mupirocin-resistant CA-MRSA.
- Retapamulin represents a promising alternative therapeutic agent for treating mupirocin-resistant CA-MRSA infections.
- Further investigation into retapamulin's efficacy in clinical settings, especially during disease clusters, is warranted.
