Case 1 occurred in a 64-year-old female who was admitted for community onset CDI. This patient had multiple risk factors for CDI, including recent antibiotic use (meropenem and vancomycin for pneumonia, and levofloxacin for chronic leukopenia) and immunosuppression. She was initially leukopenic secondary to end-stage liver disease awaiting transplantation with mild CDI (WBC 600/μL, serum creatinine 138% relative to baseline). She was treated with intravenous metronidazole 500 mg three times daily for CDI starting on hospital day 1. On hospital day 2, follow-up PCR for toxigenic C. difficile remained positive. Her early hospital course was unremarkable; however, she developed ileus, nausea, and vomiting on hospital day 4 and her CDI had progressed from mild to a severe complicated case. The patient was transferred to the intensive care unit (ICU) and oral vancomycin 125 mg four times daily was added to the regimen. On hospital day 6, the patient’s ileus remained unresolved, her serum creatinine level increased to 188% of the premorbid level and she developed severe abdominal pain. Due to the concerns for limited effectiveness of oral vancomycin in the setting of ileus, intravenous tigecycline was added to the regimen on hospital day 6 as a 100-mg loading dose followed by 50-mg doses twice daily. This patient was treated with a combination of intravenous tigecycline, oral vancomycin, and intravenous metronidazole for 10 days. No side effects of tigecycline therapy were noted in the electronic medical record. Follow-up PCR for toxigenic C. difficile was negative at the end of treatment. This patient was at high risk of recurrence due to her chronic antibiotic use and pancytopenia. Therefore, she was discharged to a long-term care facility where she completed a 30-day vancomycin taper. She had no subsequent recurrence of CDI on record.
Case 6 occurred in an 84-year-old female admitted from a nursing home with altered mental status, leukocytosis (WBC 19,300/μL), and acute kidney failure (serum creatinine increased 497% relative to baseline). The patient was admitted to the ICU with severe complicated CDI with septic shock. Intravenous metronidazole 500 mg three times daily and oral vancomycin 125 mg four times daily were started on hospital day 1. The patient’s diarrhea and leukocytosis persisted (WBC 41,200/μL) and intravenous tigecycline was added on hospital day 7 as a 100-mg loading dose followed by 50 mg twice daily. She was treated with combination tigecycline, vancomycin, and metronidazole for 3 days. The patient’s diarrhea resolved and her WBC decreased yet remained elevated (WBC 33,600/μL). Tigecycline was discontinued per the family’s decision to switch her to oral antibiotics for discharge to hospice. This patient was classified as clinical failure due to non-resolving leukocytosis and sustained response was unevaluable due to the lack of clinical cure. No side effects associated with tigecycline use were noted in the electronic medical record.