The various types of common skin and soft tissue infections (SSTI) present unique questions regarding outpatient management in the era of CA-MRSA. For abscesses, which are now predominantly caused by CA-MRSA, it is unclear whether or not treatment with antibiotics active against this pathogen are additionally efficacious compared to incision and drainage alone. For infected wounds with drainage, CA-MRSA is also a major pathogen and recommended treatments include TMP/SMX and clindamycin. However, it is unclear which of these antibiotics that otherwise possess different antimicrobial spectra is more efficacious. Etiologic investigations of cellulitis without drainage using tissue specimens and conventional and non-conventional identification methods suggest that streptococci are the principal pathogens. Antibiotics such as cephalexin, which do not possess MRSA activity, are recommended. However, with CA-MRSA’s emergence, this pathogen’s role in cellulitis is unclear, as is whether a drug with both MRSA and streptococcal activity, such as clindamycin, would be more efficacious than one with streptococcal but no MRSA activity, such as cephalexin.

Objective:

The objective of this study is evaluate oral off-patent antibiotics for outpatient treatment of patients with any of the 3 main types of acute SSTI, i.e., abscesses, infected wounds, and cellulitis, with the primary objective of determining optimal antibiotic treatment.

This is a multi-center, randomized, double-blind clinical trial conducted at 5 U.S. emergency departments in which subjects will be stratified by the type of infection and then randomized to various 7-day oral antibiotic treatments, including placebo-controlled and comparative designs.

Subjects will be enrolled over a 3 year period.  Subjects with an acute uncomplicated cutaneous abscess receiving I&D will be treated with TMP/SMX or placebo to determine whether the addition of an antibiotic with activity against CA-MRSA is more clinically efficacious than I&D alone. Subjects with an acute uncomplicated wound infection will be treated with TMP/SMX or clindamycin to determine if clindamycin, an antibiotic with activity against CA-MRSA, MSSA, and streptococci is more clinically efficacious than TMP/SMX, an antibiotic with activity against CA-MRSA and MSSA. Subjects with acute uncomplicated cellulitis will be treated with cephalexin and TMP/SMX or cephalexin and placebo to determine if a regimen with the addition of TMP/SMX, an antibiotic with activity against CA-MRSA , is more clinically efficacious than cephalexin alone, an antibiotic with activity against MSSA and streptococci but not CA-MRSA.

The primary outcome will be clinical cure at the TOC in the PP population (subjects who meet enrollment criteria, have none of the exclusion criteria, complete 100% of the first 48 hours of antimicrobial therapy, and have physical follow-up at the TOC; subjects who have been determined to be a clinical failure at any time prior to the TOC who took 100% of the first 48 hours of antimicrobial therapy but who do not have physical follow-up at the TOC will also be included in the PP population. Secondary endpoints will include microbiological cure, change in the dimension of erythema, composite cure, surgical procedures, invasive and recurrent infections, infections in household contacts, and time to normal activity and until analgesics are no longer.