Short antibiotic course appears effective for small abscesses
A 10-day course of clindamycin or trimethoprim-sulfamethoxazole after incision and drainage of a small abscess is associated with a better clinical cure rate than incision and drainage alone, according to a recent study.
“The cumulative data from our investigation and that of Talan et al [N Engl J Med 2016;374:823-832] call into question the perception ... that cure rates do not improve with the addition of systemic antibiotic treatment after incision and drainage,” said the researchers.
Participants were 786 outpatients (281 children and 505 adults, mean age, 25.5 years, 57 percent male), each with a single skin abscess ≤5 cm in diameter and accompanied by ≥2 of the following symptoms for ≥24 hours: erythema, swelling or induration, purulent drainage, tenderness, or local warmth. The abscesses were incised and drained and patients were subsequently randomized to receive a 10-day course of oral clindamycin (300 mg TID, n=266), trimethoprim-sulfamethoxazole (80 mg trimethoprim + 400 mg sulfamethoxazole BID, n=263), or placebo (n=257).
Sixty-seven percent of patients (n=527) were positive for Staphylococcus aureus (S. aureus) and 49.4 percent (n=388) positive for methicillin-resistant S. aureus (MRSA).
Clinical cure rate at 7–10 days post-therapy was comparable between patients on clindamycin and trimethoprim-sulfamethoxazole (83.1 percent vs 81.7 percent; rate difference -1.3 percentage points; p=0.73) and superior to that of placebo (68.9 percent; rate difference -14.2 and -12.9 percentage points; p<0.001 for both comparisons). [N Engl J Med 2017;376:2545-2555]
Cure rates were comparable between patients on clindamycin and trimethoprim-sulfamethoxazole who tested positive for S. aureus (83.5 percent vs 83.2 percent; p=0.99), and higher than that of patients on placebo (63.8 percent; p<0.001 for both comparisons). Similar results were demonstrated among patients who tested positive for MRSA (81.7 percent [clindamycin] vs 84.6 percent [trimethoprim-sulfamethoxazole]; p=0.63 compared with 62.9 percent of patients on placebo (p<0.001 and p=0.001 when compared with clindamycin and trimethoprim-sulfamethoxazole, respectively).
In patients without S. aureus, cure rate was similar among all treatments (83.8, 81.9, and 83.1 percent of patients treated with clindamycin, trimethoprim-sulfamethoxazole, and placebo, respectively; p=0.99 for all comparisons).
At 1-month follow-up, 78.6, 73.0, and 62.6 percent of patients initially treated with clindamycin, trimethoprim-sulfamethoxazole, and placebo, respectively, remained cured.
Patients whose abscesses were initially cured with clindamycin had a lower likelihood of new infections (at a different site or recurrence at original abscess site) at 1-month follow-up (6.8 percent) compared with those initially given trimethoprim-sulfamethoxazole (13.5 percent; p=0.03) or placebo (12.4 percent; p=0.06).
More patients on clindamycin reported an adverse event (21.9 percent) compared with those on trimethoprim-sulfamethoxazole (11.1 percent) or placebo (12.5 percent), with the most common adverse events being diarrhoea (16.2, 5.4, and 6.7 percent, respectively) and nausea (2.3, 4.2, and 2.4 percent, respectively). Of the nine serious adverse events reported, only one was deemed treatment-related (trimethoprim-sulfamethoxazole-related hypersensitivity).
“Our findings show a clinical benefit of antibiotic therapy in addition to incision and drainage that seems limited to patients with S. aureus infection,” said the researchers, who acknowledged that a longer follow-up period may have resulted in the detection of more recurrences.
“Our findings suggest that there is a trade-off between more adverse effects and a lower likelihood of infection recurrence when one uses clindamycin rather than [trimethoprim-sulfamethoxazole]. Such information and the local prevalence of resistance should be used by treating physicians and policy makers when choosing an antibiotic for adjunctive therapy of cutaneous abscesses,” they said.