Outbreak of Pseudomonas aeruginosa infections caused by commercial piercing of upper ear cartilage

Context Sporadic infections following ear piercing are well documented, but common-source outbreaks are rarely recognized. Objective To investigate reports of auricular chondritis subsequent to commercial ear piercing. Design, Setting, and Subjects Outbreak investigation by Oregon public health agencies, including cohort study of persons pierced at a jewelry kiosk in August-September 2000, environmental sampling, and molecular subtyping of isolates. Confirmed cases had Pseudomonas aeruginosa cultured from ear wounds. Suspected cases had signs and symptoms of external ear infection, including drainage of pus or blood for at least 14 days. Main Outcome Measures Risk factors for infection and comparison of bacterial isolates by molecular subtyping. Results From 186 piercings in 118 individuals, we identified 7 confirmed P aeruginosa infections and 18 suspected infections. Confirmed cases were 10 to 19 years old. Most were initially treated with antibiotics ineffective against Pseudomonas. Four were hospitalized, 4 underwent incision and drainage surgeries (1 as an outpatient), and several were cosmetically deformed. Upper ear cartilage piercing was more likely to result in either confirmed or suspected infection than was lobe piercing (confirmed: RR undefined, P<.001; suspected: RR, 3.6; 95% confidence interval, 1.5-8.5). All persons with confirmed infections had their ear cartilage pierced With an open, spring-loaded piercing gun. Patient isolates were indistinguishable by molecular subtyping, and matching isolates were recovered from a disinfectant bottle and nearby sink. At least 1 worker admitted sometimes spraying the disinfectant on the ear studs before piercing. Conclusions Ear cartilage piercing is inherently more risky than lobe piercing. Clinicians should respond aggressively to potential auricular chondritis and consider Pseudomonas a possible cause pending culture results.