Trueperella pyogenes bacteremia in a patient with nasal NK/T-cell lymphoma: A case report

Abstract

Trueperella pyogenes is a well-known pathogen that causes opportunistic infections in farm animals, especially cattle and pigs. However, human infections are extremely rare and typically linked to occupational exposure. In this report, we present a case of sepsis due to T. pyogenes in an immunocompromised patient. A 75-year-old male patient, with a background of chronic obstructive pulmonary disease and a history of livestock farming, was admitted with headache, nasal congestion, dyspnea, and hypotension. He was hypoxic, pancytopenic, and severely hyponatremic, with elevated inflammatory markers. A biopsy from a maxillary sinus mass revealed nasal-type NK/T-cell lymphoma. Two sets of blood cultures (each consisting of two aerobic and one anaerobic bottle) were collected from separate venipuncture sites 24 h apart. A growth signal was detected on day two, and T. pyogenes was isolated from all bottles across both sets. Beta-hemolytic colonies grew on sheep blood agar; Gram staining revealed pleomorphic Gram-positive rods. The isolate was catalase and oxidase negative and identified as T. pyogenes via VITEK-MS. Susceptibility testing showed resistance to trimethoprim-sulfamethoxazole and susceptibility to penicillin, tetracycline, clindamycin, rifampin, linezolid, and vancomycin. Empirical treatment with meropenem, vancomycin, and levofloxacin was initiated; dexamethasone was added due to suspected lymphoma infiltration. By the fifth day, respiratory symptoms and fever had resolved, and inflammatory markers normalized. The patient was discharged with oral methylprednisolone for lymphoma and levofloxacin for antimicrobial therapy. This case highlights the importance of recognizing T. pyogenes as a rare but significant human pathogen, especially in immunocompromised individuals with animal exposure, and underlines the need for advanced identification methods in clinical microbiology.