Microbiology Case Study: A 70 Year Old Male with a Decubitus Ulcer

Clinical History

A 70 year old male with a history of multiple system atrophy and left hip fracture presented to his primary care physician after being found by his home health nurse to have a sacral decubitus ulcer. Physical examination revealed an afebrile immobile patient with a 3.0 cm stage III ulcer over the sacrum with purulent exudate. Tissue was obtained and sent to our laboratory for Gram stain and culture.

Laboratory Findings

Gram stain was significant for many polymorphonuclear neutrophils and mixed gram positive and gram negative organisms. Blood and chocolate plates grew mixed organisms with a predominant gram positive coccobacillus. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) identified this organism as Trueperella bernardiae.

Image 1. Gram stain from tissue showing mixed gram positive and gram negative organisms.
Image 2. Blood agar showing non-hemolytic white colonies.

Discussion

Trueperella bernardiae is a nonspore-forming, facultatively anaerobic, gram-positive coccobacillus. It was previously categorized within the Actinomyces and Arcanobacterium genera. It is classically associated with pig farming. It is often considered to be a contaminant or normal flora, however, it has been reported as a cause of bone and soft tissue infections. Highly invasive diseases are rare. The incidence of infection may have been underreported previously due to the difficulty to culture and identify it from normal flora prior to the advent of MALDI-TOF. Antibiotic sensitivity data is limited, however, there are reports of susceptibility to beta-lactams, clindamycin, tetracycline, and vancomycin. Minimum inhibitory concentration interpretation is often based on data from bacteria of the Corynebacterium.

References

  1. Rattes ALR, Araujo MR, Federico MP, et al. Trueperella bernardiae: first report of wound infection post laparoscopic surgery. Clin Case Rep. 2016 Aug;4(8):812-815.
  2. Lawrence CHD, Waseem S, Newsholme W, Klein JL. Trueperella bernardiae: an unusual cause of septic thrombophlebitis in an injection drug user. New Microbes New Infect. 2018 Nov;26:89-91.
  3. Cobo F, Rodriquez-Granger J, Sampedro A, et al. Two Rare Cases of Wound Infections Caused by Trueperella bernardiae. Jpn J Infect Dis. 2017;70:682-684.
  4. Gowe I, Parsons C, Best M, et al. Successful treatment of olecranon bursitis caused by Trueperella bernardiae: importance of environmental exposure and pathogen identification. Case Reports in Infectious Diseases. 2018;5353085.

-Jonathan Wilcock, MD is a 1st year anatomic and clinical pathology resident at the University of Vermont Medical Center.

-Christi Wojewoda, MD, is the Director of Clinical Microbiology at the University of Vermont Medical Center and an Associate Professor at the University of Vermont.

One thought on “Microbiology Case Study: A 70 Year Old Male with a Decubitus Ulcer”

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s