Case 7 occurred in a 73-year-old female who was initially admitted due to pneumonia and acute kidney injury. The patient was treated empirically with vancomycin, levofloxacin, and piperacillin-tazobactam. On hospital day 3, the patient developed copious diarrhea, nausea, leukocytosis (WBC 20,000/μL) and serum creatinine increased 151% of the premorbid level. Clostridium difficile toxin was detected and oral metronidazole 500 mg three times daily was initiated. Tigecycline was added on hospital day 5 based on recommendations by the consulting infectious diseases specialist. Tigecycline was initiated instead of vancomycin due to the additional coverage of the patient’s concomitant vancomycin-resistant enterococcal urinary tract infection. The patient was successfully treated with 4 days of combination therapy with tigecycline and metronidazole with resolution of all CDI symptoms. No side effects attributed to tigecycline use were noted, and she had no documented CDI recurrence 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.