Case 91

1. Presented by Eitan Halper-Stromberg MD and Karen Carroll MD

An adult patient a past medical history of long-standing diabetes, presents with altered mental status, vomiting, and tachycardia to the 200s. EMS found the patient unresponsive, and per report had not taken their insulin recently. Prior to EMS being called, the patient had recently presented to urgent care with lower extremity cramping, and was treated for a presumed strained muscle. On exam the patient appears severely dehydrated, tachypneic, and has a decreased level of consciousness. They are transferred to the ICU and intubated for airway protection and the patient is resuscitated aggressively for severe hypotension and tachycardia. Notable labs include glucose 800, HgA1C 16, lactate 2.5, and anion gap 36. Though the gram stain of a blood culture bottle that signaled positive was initially read as negative, the more sensitive acridine orange stain demonstrated a multitude of fluorescent, curved, rod-shaped bacteria.

The organism grew in an anaerobic bottle but not the aerobic bottle collected from the blood. Plating on standard media, MacConkey agar and 5% SBA, did not yield discernable colony growth. After plating on chocolate agar media, left and a charcoal based media, right, and storing in microaerophilic conditions (10% CO2, 5% O2, 85% N2) the following is seen:

Catalase and Oxidase tests were both positive. Identification was ultimately discerned with MALDI-TOF-MS. The organism was further tested for antibiotic susceptibility, with susceptibilities to erythromycin (macrolide), ciprofloxacin (quinolone) and doxycycline (tetracycline). It also appeared susceptible to meropenem and resistant to ampicillin, though CLSI breakpoints do not exist officially for this organism for these two antibiotics. The ID fellow, upon discovering the identity of the microbe, hypothesized that the patient's hypotension with subsequent PEA precipitated bowel ischemia which then provided the opportunity for the bacteria to translocate from the bowel to the bloodstream.

Which organism is most likely?