Prevalence of mupirocin resistance in clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis: results of the Antimicrobial Resistance Surveillance Study of the Paul-Ehrlich-Society for Chemotherapy, 2001

A multicentre surveillance study comprising 26 laboratories located in Austria, Germany, and Switzerland was carried out in November 2001. A total of 787 isolates of Staphylococcus aureus and 456 isolates of Staphylococcus epidermidis mainly recovered from hospitalised patients, were tested. MICs for mupirocin were determined using the broth microdilution procedure. Breakpoints were ≤4 mg/l (susceptible), 8–256 mg/l (low-level resistance) and ≥512 mg/l (high-level resistance). Rates of low- and high-level resistances were 2.9 and 0.9% in S. aureus, and 9.4 and 3.3% in S. epidermidis, respectively. Mupirocin resistance was almost exclusively observed in oxacillin-resistant isolates of S. aureus (MRSA) and S. epidermidis (MRSE). High-level mupirocin resistance was detected in 3.1 and 4.5% of MRSA and MRSE, respectively.