The experience of intramuscular benzathine penicillin for prophylaxis of recurrent cellulitis: A cohort study

Background/Purpose: Recurrent cellulitis is an important clinical issue but the optimal strategy for prophylaxis is not determined. Intramuscular benzathine penicillin at a 4-week interval had been adopted in our hospital and the study was conducted to evaluate the efficacy. Methods: From January 1, 2009 to May 31, 2013, all patients aged >= 18 year, with a history of recurrent cellulitis and having received at least three shots of intramuscular benzathine penicillin for prophylaxis were retrospectively recruited for analysis. Two treatment periods (prophylaxis period and nonprophylaxis period) were defined. The effects of benzathine penicillin prophylaxis and patient characteristics on the incidence rate of recurrent cellulitis were analyzed using Poisson regression model. Results: A total of 72 patients were enrolled, including 26 (36.1%) men. The most common underlying conditions were past surgery at the proximal side of the affected limb (38, 52.8%), malignancy (31, 43.1%), and diabetes mellitus (24, 33.3%). The incidence rate of recurrent cellulitis in the prophylaxis period was 0.73 episode/patient-year, significantly lower than that of 1.25 episodes/patient-year in the nonprophylaxis period (p < 0.001). Tinea pedis was a significant factor associated with increasing incidence of recurrent cellulitis in our cohort. Conclusion: Intramuscular benzathine penicillin at a 4-week interval may be an effective prophylactic strategy to reduce the incidence of cellulitis. Further studies are necessary to determine the factors associated with failure of prophylaxis as well as optimal individualized dosage and dosing interval of the prophylactic agent. Copyright (C) 2015, Taiwan Society of Microbiology. Published by Elsevier Taiwan LLC.