Recurrent Paenibacillus infection

The genus Paenibacillus includes Gram-positive bacteria that are rarely known to cause infection in humans. Here we report a case of recurrent Paenibacillus macerans infection in an otherwise healthy 66-year-old man following environmental exposure decades prior to presentation to our clinic. Despite numerous attempts at surgical debridement, Paenibacillus was repeatedly cultured from the soft tissue of the lower extremity wound site over a period of years. Post-operative antibiotic treatment prevented recurrence; however, upon antibiotic discontinuation, Paenibacillus was again cultured from the wound. After multiple rounds of debridement and antibiotic therapy, the patient was started on indefinite, low-dose trimethoprim-sulfamethoxazole therapy to suppress infection resulting from transition of Paenibacillus spores to vegetative cells. This case adds to the limited number of case reports describing Paenibacillus species infection in healthy adults and presents a unique case of bona fide P. macerans infection requiring life-long antibiotic therapy.