New, Accurate Detection Methods Necessary for Treating C. Difficile Infections

Due to the inadequacy of current methods for detecting Clostridioides difficile (CDI) infections, new and more reliable diagnostic approaches, such as microRNAs (miRNAs), must be utilized to more accurately detect and treat CDI, according to a research review published in World Journal of Gastroenterology.

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CDI was classified by the CDC as an urgent threat in a 2019 antibiotic resistance report. In patients with medically-related CDI, 1 in 11 adults over the age of 65 die within 1 month, the study authors say.

Further, although most cases of CDI occur in the hospital setting, the frequency of community-acquired CDI is rising, adding to the need for accurate and timely diagnoses, according to the investigators. There are a variety of current diagnostic tools available for detecting CDI. One of these is examining the patient’s colon through colonoscopy or through flexible sigmoidoscopy to look for inflamed areas and pseudomembranes, investigators say.

Despite the cost-effectiveness and non-invasive nature of the screening that has led to it becoming the first-line approach for CDI diagnosis, results vary widely due to different clinical microbiology methods and their different accuracy and variance, according to the review authors.

Another such assay is cell cytotoxicity neutralization, which is the first-line, fecal-based diagnostic test for CDI, and involves isolating C. difficile toxins from feces and culturing cells for at least 24 hours.

Issues with this method of diagnosis center around a lack of standard to eliminate or reduce nonspecific bacteria colonization from a C. difficile culture, and the time-consuming, labor-intensive nature of culture-based assays that require a high level of laboratory skill, the study authors explain. As a result, it is commonly used as a reference method for research and not for first-line clinical screening, despite being considered the current gold standard.

An additional method is the nucleic acid amplification test, which is a quantitative real-time-PCR-based diagnostic assay that can rapidly detect C. difficile toxins at the DNA level. Many of these tests are probe-based, which increases amplification specificity, the researchers write.

This nucleic acid-based toxin screening has more than 10 times higher sensitivity than a cytotoxin assay, but it comes with relatively low screening specificity due to high false positive cases from asymptomatic infection, the reviewers found. Due to this, optimization is required, as well as a preselection of patients based on symptoms and inflammation biomarkers to reduce the risk of a false positive.

Considering the many concerns that accompany current screening methods, miRNAs present a potentially effective pathway forward. MiRNAs are small molecules that are key regulators of gene expression and silencing at the post-transcriptional level and can act via molecular mechanisms at every step of CDI, the researchers explain.

miRNA can inhibit specific transcripts or inflammatory molecule transcription, which can influence the pathology grade. The imbalance of these biomarkers can be measured and exploited for diagnosis, and when used in conjunction with standard methods, results can be strengthened.

Although there is optimism for the use of miRNA to detect CDI, especially due to their ease of detectability in body fluids, the relationship is limited and must be researched further, the investigators write.

miRNA could be especially useful due to its role in controlling and influencing gene expression and for allowing more personalized CDI treatment. However, miRNA also may pose difficulties because it can be derived from blood cells released by different pathological events, the study authors explain.

“These reported miRNA studies can be used in conjunction with current diagnostic tools to improve diagnostic accuracy aiding in patient management for both symptomatic and asymptomatic CDI patients,” the investigators concluded.

Reference

Bocchetti M, Ferraro MG, Melisi F, et al. Overview of current detection methods and microRNA potential in Clostridioides difficile infection screening. World J Gastroenterol. 2023;29(22):3385-3399. doi:10.3748/wjg.v29.i22.3385