Increase in imported mupirocin-resistant Staphylococcus aureus from the tropics and subtropics: trends in Berlin from...

Mupirocin resistance in Staphylococcus (S.) aureus (Mup-RSA) is emerging and may lead to S. aureus decolonisation failure. Our aim was to assess temporal trends in mupirocin-resistant S. aureus (Mup-RSA) and methicillin-resistant S. aureus (MRSA) among S. aureus-positive patients presenting to the Tropical Medicine outpatient Department, also including the Dermatology Department and the overall university hospital for context.

We calculated annual percentages of Mup-RSA and MRSA among S. aureus-positive patients and modelled temporal trends using Poisson or negative binomial regression, estimating incidence rate ratios (IRR).

From January 1, 2018, to June 30, 2025, Mup-RSA was detected in 3.1% (24/782) of patients with S. aureus at the Tropical Medicine Department, 1.1% (23/2030) at the Dermatology, and 0.5% (142/28,122) at the hospital overall. The rate of Mup-RSA among S. aureus-positive patients increased over time at the Tropical Medicine (IRR, 1.64; 95% CI, 1.3 - 2.06, p < 0.01), and at the Dermatology (IRR, 1.37; 95% CI, 1.12 - 1.67, p < 0.01), but not at the hospital overall. MRSA did not increase significantly over time in either setting. MRSA in Mup-RSA was found in 4.2% (1/24), 4.3% (1/23), and 22.5% (32/142), respectively.

Mup-RSA proportions are low overall, but have increased substantially in Tropical Medicine, with modest increases in Dermatology. Clinicians should be aware of both the emergence of Mup-RSA and the availability of alternative topical agents for decolonisation, particularly in contexts where S. aureus could be imported from regions with high Mup-RSA prevalence.