School of Podiatric Medicine - Student Research

Document Type

Poster

Publication Date

Fall 9-24-2026

Abstract

Pediococcus pentosaceus (Pep) is a Gram-positive lactic acid bacterium widely utilized in food fermentation and recognized for its probiotic properties. While generally considered non-pathogenic, it can act as an opportunistic pathogen in immunocompromised hosts. Its intrinsic resistance to glycopeptides, with additional reported resistance to tetracycline and novobiocin, limits empiric treatment options and poses a diagnostic challenge when encountered in clinical cultures and deemed to be pathogenic.

We present the case of a male living with type two diabetes mellitus, hypertension, peripheral artery disease and obesity admitted with a non-healing infected diabetic foot ulcer of the great toe. Magnetic resonance imaging demonstrated osteomyelitis involving the phalanges of the first digit, quickly extending to the first metatarsal head. Wound culture grew P. pentosaceus, resistant to vancomycin and susceptible to penicillin.

Due to interest in this typically opportunistic pathogen, and in this case primary pathogen responsible for osteomyelitis of the diabetic foot, a scoping literature review was conducted using the search terms “pentosaceus AND (wound OR foot) AND infection,” yielding 1522 initial results, of which one article met full inclusion criteria. A secondary review broadening the search to the entire Pediococcus genus was subsequently performed to provide additional clinical context. The available literature predominantly described bacteremia caused by P. acidilactici in immunocompromised individuals, with no prior cases documenting lower extremity bone infection. To our knowledge, this is the first reported case of diabetic foot osteomyelitis attributable to this organism.

These findings underscore the importance of timely pathogen identification, culture-directed antibiotic selection, and early interprofessional collaboration with infectious disease specialists when managing complex diabetic foot and bone infections caused by rare or atypical organisms. Recognition of P. pentosaceus as a rare but clinically significant pathogen may improve clinical decision-making, facilitate limb salvage, and reduce patient morbidity in future encounters.

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