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.
Case 3 occurred in a 38-year-old male who was initially admitted due to acute hypoxic respiratory failure and necrotizing pancreatitis. For this infection, he was treated with piperacillin–tazobactam, which was switched to ampicillin–sulbactam after 10 days by the consulting infectious diseases specialist. On hospital day 25, the patient started developing copious diarrhea (>15 loose stools per day), fever (38.4 °C), and leukocytosis (WBC 13,500/μL) consistent with C. difficile sepsis and severe complicated CDI. The patient’s serum creatinine levels increased 143% relative to baseline. Upon confirmation of CDI on hospital day 26, intravenous metronidazole 500 mg three times daily was initiated. Tigecycline was added on hospital day 27 for dual coverage of enterococcal pancreatitis and C. difficile. Oral vancomycin 250 mg four times daily was also added at this time and metronidazole was discontinued by decision of the treating physician. Fever and leukocytosis subsided and diarrhea improved on 8 days of combination therapy with tigecycline and oral vancomycin. There was no recurrence of CDI on record.