Treatment of Skin and Soft Tissue Infections Due to Community-Associated Methicillin-Resistant Staphylococcus aureus in Europe: The Role of Trimethoprim-sulfamethoxazole

TO THE EDITOR—We read with interest the review by Chua et al [1] addressing the global epidemiological characteristics of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). The paper is a very comprehensive and detailed description of the main MRSA clones spreading worldwide and provides clinicians an overview of the most important antimicrobial resistance patterns circulating in different regions of the world. Of more importance, providing recommendations for antimicrobial therapy for skin and soft-tissue infections (SSTIs) due to CA-MRSA, according to major clones and regional data regarding susceptibility patterns, is of particular importance in the era of antimicrobial stewardship. However, while we do agree with the suggestions for the United States, Asia, and Australia, on the contrary, we were very surprised that trimethoprim-sulfamethoxazole was never mentioned among the antibiotics to be tested within the susceptibility pattern of the ST80-MRSA-IV strains, nor was it among the treatment options discussed for use in Europe. Indeed, the algorithm proposed by the authors suggests clindamycin as the only drug for empirical treatment of CA-MRSA SSTI in Europe with the notable exclusion of trimethoprim-sulfamethoxazole. As clearly outlined by the authors, especially concerning MRSA, Europe represents a very heterogeneous scenario, with respect to both the hospital and the community strains. The clone ST80 expressing SCC mec type IV is, currently, the prevalent one, although no homogeneous data are available from the different European regions and other minor clones look prevalent in specific settings, such as ST5-MRSA-I in France. ST80 CA-MRSA strains are generally characterized by phenotypic and genotypic homogeneity and a natural ability to spread [2]. As for the susceptibility patterns, the clone is typically resistant to tetracycline and expresses variable resistance to fluoroquinolones. Therefore, clindamycin represents a first-line option for the treatment of patients with SSTI due to CA-MRSA. However, to our knowledge, several European surveys have documented a substantial susceptibility of the ST80 clone to trimethoprim-sulfamethoxazole [3–6]. In particular, none of these surveys documented any trimethoprim-sulfamethoxazole–resistant strain [3–6]. To further confirm the evidence, the most recent guidelines published by the British Society for Antimicrobial Chemotherapy Working Party for the management of CA-MRSA infections recommend trimethoprim-sulfamethoxazole as a first-line agent [7]. We would also underline that recommending clindamycin as the only treatment for SSTI in Europe might be likely to be associated with some degree of risk. Katopodis et al [8] recently reported a study of 167 children with MRSA SSTI who were admitted to a central Greece hospital. Among the CA-MRSA isolates, 88.9% were resistant to fusidic acid, 77.6% to tetracycline, and 21.1% to clindamycin. None of the MRSA isolates were resistant to trimethoprim-sulfamethoxazole. Of even more concern, clindamycin resistance increased from 0% in 2003 to 31.2% in 2009 and the genomic analysis showed that the majority of the strains belonged to the ST80 clone. In our opinion, the current epidemiological characteristics of CA-MRSA in Europe strongly suggest that trimethoprim-sulfamethoxazole and clindamycin are appropriate first-line therapeutic options for the treatment of SSTI due to CA-MRSA. Potential conflicts of interest. All authors: No reported conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed in the Acknowledgements section.