Effective Antibiotic Treatment of MRSA

Effective Duration of Antibiotic Treatment of Community-Acquired Methicillin-Resistant Staphylococcus Aureus (MRSA)

To evaluate the effective duration (in days) to clinical improvement of outpatient antibiotic regimens in the treatment of superficial abscesses caused by MRSA in patients that present to the emergency department.

Skin and soft tissue infections-cellulitis, furuncles, carbuncles, and abscesses-make up approximately 1-2% of emergency room visits annually. While abscesses are generally incised and drained, there is no definite standard treatment regimen or duration of treatment that practitioners have adhered to regarding antibiotic use. Historical evidence suggests that antibiotics may not be necessary for simple superficial abscesses, though a number of antibiotics-including penicillins and cephalosporins-may be used for treatment of large and/or complicated abscesses. These antibiotics however are ineffective against what is becoming an increasingly common pathogen- community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). At our institution, it is estimated that 60-70% (unpublished observation) of cultured abscesses are caused by CA-MRSA. These patients have generally been treated with incision and drainage, with the addition of an antibiotic left to the practitioner's discretion. Also, there has been no universally accepted duration of treatment established to observe clinical improvement of such abscesses. Common antibiotic regimens range from 7-14 days of treatment for cellulitic infections. While there has been one prospective trial regarding the use of antibiotics in simple abscesses, there has been no published prospective study on the use of antibiotics in treating CA-MRSA abscesses in adults. Furthermore, while 7-14 days of treatment seems the recommended duration of treating cellulitic infections, no study has evaluated the duration of treatment needed to observe clinical improvement of abscesses caused by CA-MRSA. We wish to prospectively evaluate the duration of treatment necessary to observe clinical improvement of abscesses caused by CA-MRSA among multiple different antibiotics (ie. cephalexin, clindamycin, and trimethoprim/sulfamethoxazole) after standard incision and drainage in patients presenting to the emergency department.

To determine the effective duration of treatment of different antibiotic regimens in the treatment of abscess with regards to resolution of patient symptoms and signs.

Treatment failure will be defined as an increase in patient symptoms, increase in abscess size, development of constitutional symptoms, or hospitalization secondary to abscess complications

Inclusion Criteria: All patients age 18 and older, presenting to the emergency department with an abscess with a diameter greater than three centimeters Informed consent Exclusion Criteria: Patients who are presumed to have community-acquired pathogens Under 18 Abscess less than three centimeters in diameter