Placebo Controlled Study of Antibiotic Treatment of Soft Tissue Infection

This study is to determine whether antibiotic therapy is needed for patients with non-life threatening soft tissue infections. Most patients with these soft tissue infections are presently treated with antibiotics. Many of these infections resolve without proper antibiotic treatment. Treatment of patients with antibiotics after surgical drainage of an abscess may not be necessary and indiscriminate use of antibiotics may lead to colonization by drug-resistant organisms. Subsequent infection by drug resistant organisms may limit the choice of antibiotics in more complicated infections. A comparison between antibiotic treatment and no antibiotic treatment in surgically treated, uncomplicated soft tissue infections is needed to address this very important question.

The Integrated Soft Tissue Infection Service (ISIS) Clinic at San Francisco General Hospital treats a large number of patients with soft tissue infections, and our data suggest that antibiotics may be overused for these infections. Most of these infections are treated by surgical drainage of an abscess (77%). When microbiologic cultures were performed, 88% of the abscesses were infected with Staphylococcus aureus (S. aureus), and 55% of the abscesses contained methicillin-resistant Staphylococcus aureus (MRSA). Recently, the high prevalence of MRSA infection has been documented in San Francisco and throughout the country. Presently, most patients are treated with antibiotics after drainage of the abscess. Our retrospective analysis found that 60% of these infections resolved without appropriate antibiotic treatment. These were patients infected with MRSA who were treated with an antibiotic that was not active against that organism. This implies that surgical drainage of these abscesses was probably the important treatment and antibiotic treatment was probably not necessary. Unnecessary use of antibiotics has adverse consequences. Some patients have allergic reactions to antibiotics. Patients can develop serious gastrointestinal infections from antibiotic use. Antibiotics are costly. But most importantly, overuse of antibiotics may be the significant factor in the spread of antibiotic resistant organisms. The increased prevalence of MRSA has made it extremely difficult to treat patients with appropriate antibiotics in life threatening infections (i.e. bacterial endocarditis, osteomyelitis, and necrotizing soft tissue infections). The experience in the ISIS Clinic has brought into question our present practice of antibiotic use in patients with surgically managed abscesses. Many surgeons practicing in the ISIS clinic believe that antibiotics have little or no effect on the clinical course of these uncomplicated infections. Elimination of antibiotic use for these uncomplicated infections would certainly simplify care for these patients. It is even possible that decreased antibiotic use may decrease the prevalence of MRSA colonization in this population. However, decreased prevalence of MRSA colonization will not be specifically addressed in this limited study. A randomized, prospective and blinded trial comparing standard antibiotic treatment with no treatment should help determine whether antibiotics are really needed for these infections.