Bacteriological and clinical studies of sulfamethoxazole-trimethoprim ointment therapy against decubitus infected with methicillin-resistant

The antibiotic sensitivity and in vitro acquired drug resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolated from infected decubitus of six patients to sulfamethoxazole-trimethoprim (ST), vancomycin (VCM), arbekacin (ABK) and minocycline (MINO) were investigated. ST was as active as VCM, ABK and MINO against the MRSA isolates. The above six strains acquired a moderate degree of drug resistance against ST. The level of drug resistance against ST was almost the same as that against VCM, ABK and MINO. However, no marked resistance occurred to these four agents. We applied an ointment (Elase®) containing 0.024% of ST everyday to six patients who had decubitus infected with MRSA. Open decubitus of six patients healed and closed within 34 days (mean) after initiation of this therapy, and the clinical effects were good in all cases. No drug resistance to ST of the MRSA isolated from six cases occurred during or after therapy. Transient photosensitivity was observed in one patient when a 0.048% ST ointment was used, but disappeard when it was replaced with a 0.024% ST ointment. From these results, we conclude that ST ointment therapy is useful for the treatment of decubitus infected with MRSA.