Case 4 occurred in an 80-year-old female who was admitted due to increasing fatigue and copious diarrhea consistent with community onset CDI. Her risk factors for CDI included advanced age and recent antibiotic use (vancomycin, levofloxacin, and piperacillin–tazobactam). This patient’s initial severity of illness was mild (WBC 9,100/μL, serum creatinine 116% of the premorbid level) and she was treated with oral metronidazole 500 mg three times daily beginning on hospital day 1. After 3 days of metronidazole treatment, her abdominal pain had improved, but the diarrhea persisted and her WBC began trending upward (16,500/μL). On hospital day 4, the patient developed septic shock secondary to CDI. As her CDI had progressed to a severe complicated case, intravenous tigecycline and vancomycin 250 mg four times daily were added. Tigecycline was given as a 100-mg loading dose followed by 50 mg twice daily. The patient was treated successfully with 6 days of triple therapy with tigecycline, vancomycin, and metronidazole. Due to the high risk of CDI recurrence in this patient, a vancomycin taper was completed. The patient was discharged to home and had no CDI recurrence within 28 days of follow-up.
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.