85 year old patient on treatment with moxifloxacin for a respiratory infection admitted for vomiting, diarrhoea and fever of 38.5o C; with hypoalbuminaemia of 2.62 g/dL, serum creatinine (Crs) around 1 mg/dL and a clearance calculated according to the Cockcroft-Gault equation of 38.26 mL/min.
A diagnosis of severe and complicated CDI without abdominal distension was made according to the criteria established in the guidelines for the diagnosis, treatment and prevention of CDI3 and intravenous metronidazole 500 mg 3 times a day plus oral vancomycin 500 mg four times a day was prescribed. After 3 days of treatment, trough plasma vancomycin levels of 5.77 μg/mL are detected. This value increases to 10.81 μg/mL on the sixth day of treatment. After 7 days, following resolution of the diarrhoea and a negative stool toxin result, antibiotics are discontinued.