Do you switch to an alternative agent for C difficile colitis for a patient with suspected infection and positive testing who continues to have >3 watery bowel movements daily despite multiple days of oral vancomycin treatment?

The question about switching to another agent for Clostridioides difficile (Cdif) colitis in a patient who tests positive for Cdif but continues to have diarrhea despite multiple days of oral vancomycin treatment does not include any information regarding the clinical status of the patient, the presence of co-morbid conditions, and whether this is a first or recurrent episode. Furthermore, we do not know if this patient’s diagnosis is based on NAAT positivity alone or if the patient is also toxin positive. If we assume this is a first episode and the patient was started on oral vancomycin 125mg p.o. QID, the Infectious Disease group in our healthcare system usually waits about 5-7 days while closely monitoring the patient’s response. In add...

I don't know if all nucleic acid-based tests for C. difficile are quantitative, but the most commonly used tested is cobas C. diff by Roche. The test results are reported qualitatively for some reason. Y'all have gotten used to cycle thresholds, but I, in a former life, ran thousands of RT-Q-PCR assays. A few years back, the surgeon/brother-in-law was questioning if his patient with C. diff was improving or not on PO vanco. I knew she was, because, as Dr. @Dr. First Last mentioned, you need the other parameters of the patient, such as frequency, fever, WBC, bandemia, pulse, etc. I knew these were all improving, but the patient was still having diarrhea. I went to the Micro lab and asked if they could re-run the cobas assay and give me the c...