A 62-year-old man with type 2 diabetes mellitus,
chronic kidney disease, and a history of ventricular tachycardia
with an automated implantable cardiac defibrillator (AICD) came to
his primary care physician (PCP) with symptoms of shaking,
weakness, and vomiting. He denied fevers. The physical examination
was unremarkable except for the presence of chronic peripheral
neuropathy. The physician ordered routine blood tests and 2
peripheral blood cultures, diagnosed the patient with a nonspecific
viral syndrome, and sent him home.
The routine laboratory tests done that day
revealed only a normocytic anemia. However, 5 days later, the PCP
was notified that both sets of blood cultures were growing
Corynebacterium spp. Uncertain of how to interpret the
result (as this bacteria may represent contaminated blood cultures
rather than a true cause of disease), the PCP contacted an
infectious disease specialist, who recommended hospitalization. The
patient was hospitalized, seen by a different infectious disease
specialist, and started on IV antibiotics. The patient's subsequent
evaluation revealed no evidence of infection, including an
unremarkable abdominal CT scan and a normal transthoracic
echocardiogram (TTE). Repeat blood cultures (drawn before
antibiotics were begun) remained negative. The patient was
clinically stable, so the antibiotics were stopped and the patient
was discharged to home. The physicians assumed that the
Corynebacterium was a contaminant from the skin.
One month later, the patient presented to the
emergency department (ED) with nausea and vomiting. His physical
examination and laboratory test results were unremarkable. His
symptoms improved with IV fluids, and he was discharged after an
Two days later, 2 out of 2 blood cultures drawn
at that ED visit started growing Corynebacterium spp. That
evening, the results were reported to a covering physician who was
unfamiliar with the patient or previous culture results. The
physician assumed that the blood cultures were contaminated from
the skin and took no action.
Three weeks later, the patient was readmitted
after being shocked by his defibrillator (AICD). A transesophageal
echocardiogram (TEE) revealed a tricuspid vegetation and blood
cultures again showed Corynebacterium spp. (the final
speciation was never determined). Diagnosed with subacute bacterial
endocarditis and treated with IV vancomycin, the patient made a
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