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 5 occurred in a 68-year-old male who was admitted to the hospital for febrile neutropenia secondary to pre-B cell acute lymphoblastic leukemia. This patient had multiple risk factors for CDI, including advanced age, hematologic malignancy, multiple prior antibiotic use (trimethoprim–sulfamethoxazole, levofloxacin, linezolid, and cefepime), prior chemotherapy use, and hospitalization. On hospital day 6, the patient developed acute respiratory distress and severe sepsis (4/4 SIRS criteria). On hospital day 7, the patient developed diarrhea and C. difficile toxin was detected. This case was classified as severe complicated CDI and treated initially with two days of intravenous metronidazole 500 mg three times daily and oral vancomycin 125 mg four times daily. On hospital day 9, tigecycline was added due to persisting diarrhea (>800 mL liquid stool) and fever (38.2 °C). The patient’s fever resolved on hospital day 11, diarrhea resolved on hospital day 14, and clinical cure was achieved. Triple therapy with tigecycline, vancomycin, and metronidazole was continued for a total of 21 days due to concerns for recurrence in the context of the patient’s pancytopenia. At this time, the patient was switched to palliative care due to underlying cancer with a poor overall prognosis. He tolerated treatment with tigecycline well and no side effects were reported. The patient was discharged home to hospice with no further CDI treatment. Sustained response was unevaluable due to death within 28 days of tigecycline completion.