S116 – Microbiology of PTA in the Age of Antibiotic Resistance

Abstract

ObjectivesNumerous publications have demonstrated Group A Streptococcus pyogenes is the most common pathogen isolated from peritonsillar abscesses (PTAs). We have noted multiple patients presenting with PTAs despite being recently treated with penicillin for tonsillitis. The objective of this study was to assess the bacterial content of PTAs in our practice to determine proper antibiotic therapy.MethodsA retrospective chart review was conducted at 2 tertiary care hospitals. Charts of patients diagnosed with PTA from 2001 through 2005 were reviewed for microbiology studies. If cultures were drawn, the microbiology content and any available sensitivities were assessed.Results205 patients were given the diagnosis of PTA, with an average age of 26. Of these, 64 patients (31.2%) had culture results available for study. Most cultures demonstrated mixed organisms. At least 35.9% demonstrated anaerobic organisms, most commonly Fusobacterium species (20.3%). The 3 most common aerobic organisms isolated were Group A Streptococcus pyogenes (18.8%), Group C Streptococcus (15.6%), and Streptococcus viridans (14.1%). Interestingly, 1 culture (1.6%), grew Escherichia coli as a single pathogen and 2 cultures (3.1%) grew Group D Streptococcus resistant to clindamycin.ConclusionsMost prior studies of PTAs have found Streptococcus pyogenes to be the most common isolate. Our review of 64 cultures found the most frequent pathogen to be anaerobic species, particularly those from genus Fusobacte‐rium. Interestingly, at least 8 cultures (12.5%) isolated pathogens not sensitive to the antibiotic most commonly used in our practice after incision and drainage. These results support the use of broader spectrum antibiotics in the treatment of periton‐sillar abscess.