By Ethan Covey
The use of C diff Banana Broth (Hardy Diagnostics) may improve surveillance testing for Clostridioides difficile infection (CDI) and optimize workflow for C. difficile screening, which would eliminate the need for anaerobic culturing, according to a poster presented at the ASM Microbe 2024 conference.
“A lack of CD [C. difficile] surveillance programs is a gap in preventing infections and transmission events due to the complexity of anaerobic culture for CD,” wrote the authors of the poster, who are affiliated with the Massachusetts Host-Microbiome Center of Mass General Brigham, Harvard Medical School, in Boston.
To address this issue, the researchers worked to develop an alternative approach to detecting asymptomatic C. difficile, which would be able to be widely implemented across clinical laboratory settings.
To compare the performance of the Banana Broth, which turns yellow when a positive reaction occurs, with the hospital’s original anaerobic method, rectal swabs previously identified as C. difficile–positive (n=30) and –negative (n=30) were added to tubes containing the Banana Broth. The tubes were incubated for 48 hours at 37° C and monitored every day to detect turbidity and note any change to the yellow color.
The sensitivity of the Banana Broth was determined to be 100%, specificity was 85%, positive predictive value 83% and negative predictive value 100%, according to the researchers.
To improve specificity, the researchers tested 40 rectal swabs using the Banana Broth plus C. Diff Quik Chek Complete (TechLab) and the Xpert C. difficile polymerase chain reaction assay (Cepheid).
There was a 93% concordance between the methods, and the optimized testing method detected three additional positive samples.
“Our findings demonstrate the potential use of BB [Banana Broth] as an alternative selective media for the isolation of CD in a broad range of healthcare facilities,” the authors wrote.
