Microbiology Case study: 48 Year Old Male with Multiple Injuries Following a Motorcycle Accident

Case History

The patient is a 48 year old male who presented after a motorcycle crash where he slide sideways into a ditch. He did not lose consciousness. At presentation he complained of pain across the abdomen, right wrist and left shoulder. He also had shortness of breath and chest wall pain. He denied hitting his head and was helmeted. He underwent exploratory laparotomy with repair of traumatic diaphragmatic hernia and left chest tube placement with post-operative course complicated by significant leukocytosis and bandemia on post-operative day 5 which triggered CT re-imaging of the chest/abdomen/pelvis. This study demonstrated intraperitoneal free air that prompted repeat exploratory laparotomy with subtotal colectomy with the abdomen open and wound vac in place. On post-operative day 9 the patient had an increasing white count that prompted return to OR with bowel staple line demonstrating leak, which prompted a small bowel resection, and ileostomy formation. After leaving the OR, the patient experienced worsening septic shock. Aggressive antibiotic therapy and IV fluid resuscitation was continued. Blood cultures taken on post-operative day 9 grew a large Gram positive rod. Growth of this organism was seen both aerobic and anaerobically.

Laboratory Identification

Image 1. Gram stain of the anaerobic blood culture bottle showing gram positive/variable rods.


Image 2. Aerobic blood agar plate showing small clear colonies.

Blood cultures showed box shaped gram positive/ variable rods that were growing on blood agar plates both aerobe and anaerobically. It was motile, indole and catalase negative, and esculin positive, and was identified by the MALDI to be Clostridium tertium.


Clostridium tertium is an aerotolerant gram positive rod that is widely distributed in the soil and can also be found the GI tract of animals and humans (1). C. tertium is non-toxin producing and produces terminal spores in anaerobic conditions (2). Infection with C. tertium is uncommon though it has been increasing in frequency as a cause of bacteremia, especially in patients with neutropenia, the immunocompromised, those with hematologic malignancy, those with inflammatory bowel disease, and in people with abdominal trauma or who have undergone abdominal surgery. Less commonly, C. tertium can be isolated in spontaneous bacterial peritonitis, enterocolitis, meningitis, septic arthritis, necrotizing fasciitis, post-traumatic brain abscess, and complicated pneumonia in mono- or polymicrobial infections (1). Additionally there has been a link between C. tertium infection and attempted suicide with the herbicides containing Glyphosate, as it causes GI toxicity which alters the gut environment (2). As with Clostridium difficile, the use of broad-spectrum antibiotics such as third-generation cephalosporins might predispose to intestinal colonization with C. tertium (1).

Increases in the diagnosis of C. tertium may be related to better diagnostic equipment such as the MALDI as it can easily be confused with a facultative anaerobic Bacillus or Lactobacillus species due to its gram variable appearance and ability to grow in aerobic conditions. A distinguishing feature between Bacillus species and C. tertium is negatively of the catalase reaction as Bacillus should be positive. Lactobacillus can still be a challenge as they are also catalase negative.

The treatment of C. tertium infection is complicated due to resistance to various antibiotics, including various beta-lactam antibiotics (such as third- and fourth-generation cephalosporins), clindamycin, daptomycin, and cotrimoxazole. Older reports state resistance to metronidazole, but this has not been confirmed in more recent publications. Available data indicate sensitivity to vancomycin, carbapenems, and quinolones (1)(3).


  1. Salvador F, Porte L, Durán, L, Marcotti A, Pérez J, Thompson L, Noriega LM, Lois V, Weitzel T. Breakthrough bacteremia due to Clostridium tertium in a patient with neutropenic fever, and identification by MALDI-TOF mass spectrometry. International Journal of Infection Disease. 2013;17:11 (1062-1063). https://doi.org/10.1016/j.ijid.2013.03.005
  2. You M-J, Shin G-W, Lee C-S. Clostridium tertium Bacteremia in a Patient with Glyphosate Ingestion. The American Journal of Case Reports. 2015;16:4-7. doi:10.12659/AJCR.891287.
  3. Miller D, Brazer S, Murdoch D, Reller LB, Corey, GR. Significance of Clostridium tertium Bacteremia in Neutropenic and Nonneutropenic Patients: Review of 32 Cases. Clinical Infectious Diseases. 2001; 32:975–8


-Casey Rankins, DO, 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.

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