Background: To evaluate the usefulness of a molecular diagnostic panel for the diagnosis and management of patients with gastrointestinal infections.
Materials/methods: Retrospective observational study of molecular panels for syndromic diagnosis of infectious gastroenteritis (GEI) BIOFIRE® FILMARRAY® GI Panel, BioFire Diagnostics (bioMérieux) conducted from January to October 2019. The results of the traditional microbiological techniques and variables obtained from the clinical history were also reviewed.
Results: RT-PCR was performed on 54 non-shaped feces, one sample per patient. The age range was from 10 months to 92 years with a median of 33.30 years. Thirty of them were men and 24 women. Cultures were performed in 94% of the cases, viral antigens in 50%, parasites in 26% and Clostridioides difficile toxins in 48%. The indications for requesting the microarray were the severity of the condition (invasive diarrhea and / or dehydration) in 50% of the cases, base immunosuppression in 30%, travel history in the previous week in 7% and others in 13%.
The panel was negative in 57% of cases, detected Campylobacter sp in 21%, C. difficile toxin in 8%, Salmonella sp 4% and other enteropathogens (8%). Seven coinfections were detected by the molecular panel (13%) and none by traditional techniques.
There was an agreement between the results of the microarray and traditional microbiological methods in 84% of cases (kappa_0.687).
Table 1: Distribution of positive tests by classical techniques and by PCR
* PCR was performed in all cases (54) but traditional tests only when expressly requested under clinical criteria (the table reflects the total of each type performed)
There was a therapeutic modification in 63% of the cases in which the panel was requested due to the severity of the diarrhea, in 54% of the cases in which the PCR was performed due to travel history, in 40% when the cause was immunosuppression and when the cause was unknown, no therapeutic change was assumed.
The BIOFIRE® FILMARRAY® results had an average delay of 12 hours vs an average of the traditional techniques of 26 hours (range: 2-72).
Conclusions: The agreement between traditional techniques and PCR is substantial (kappa: 0.6) although it is far from perfect. The average time saved by PCR, its greater range of potential diagnoses per test and the possibility of detecting coinfections can allow effective and faster clinical decisions.