Polymicrobial Osteomyelitis in a Patient With Isolation of Trueperella bernardiae: A Case Report and Literature Review

Abstract

Background: Trueperella bernardiae is a Gram-positive rod that has been described as an opportunistic pathogen in immunocompromised patients. In a significant number of documented cases, infections with Trueperella bernardiae have been associated with polymicrobial infections, which highlight the fact that important bacteria-bacteria relations might be involved in the natural course of these infections, especially in patients with chronic disease courses and a history of multiple antibiotic treatments. Case Presentation: We present a case of a 24-year-old woman with a 3-year history of a chronic pressure ulcer on the right foot associated with varus and cavus deformity. As per relevant medical history, she was positive for multiple wound healing sessions with wound debridement and a large number of antibiotic treatments with minimal improvement. Microbiological cultures were taken from the wound, and a soft tissue infection diagnosis was initially made. Empirical treatment was initiated with levofloxacin. At 48 h, cultures were positive for Providencia stuartii, Pseudomonas aeruginosa, Proteus penneri, Streptococcus agalactiae, and Trueperella bernardiae, and the susceptibility test was performed. Three weeks later, the symptoms progressed to purulent exudate of the wound and foul-smelling with the positive probe-to-bone test. Diagnosis was changed to polymicrobial osteomyelitis, and antibiotic therapy with ciprofloxacin and trimethoprim-sulfamethoxazole was prescribed for a 4-week course of treatment, achieving the complete remission of symptoms. Conclusions: Trueperella bernardiae represents an emerging bacterium that can be isolated in various clinical presentations. On osteoarticular infections, the presence of comorbidities, mobility limitations, and a history of multiple antibiotic treatments may be determinant. Their isolation as part of polymicrobial infections highlights relevant interspecies interactions. Research is still lacking in determining standardized methodologies for susceptibility testing and specific clinical breakpoints to guide clinical decisions.

Keywords: Gram-positive rod; Trueperella bernardiae; case report; literature review; polymicrobial infection.

Figure 1

(a) Culture. Trueperella bernardiae culture on phenylethyl alcohol agar. (b) Amplification of Trueperella bernardiae colonies. Small, whitish, nonhemolytic, and rounded colonies are observed. (c) Gram staining of Trueperella bernardiae (100X). Gram-positive cocco-bacilli are shown.