Multiplex Gastrointestinal Panel Testing in Hospitalized Patients With Acute Diarrhea in Thailand

Multiplex gastrointestinal (GI) panel testing is widely used for outpatient diagnosis of diarrhea. However, the clinical practicality of multiplex testing in hospitalized diarrheal subjects has not yet been thoroughly elucidated.

We enrolled hospitalized subjects with acute diarrhea. The subjects' stool samples were collected in triplicate; 1 sample was tested using traditional diagnoses, and the other 2 were tested using Allplex (AP) and FilmArray (FA) GI panel testing. Clinical data were reviewed and analyzed.

Of the 199 subjects, 92 (46.5%) were male, and the mean age was 66.3 years. The median (interquartile range) onset of diarrhea was 6 (2--14) days after hospitalization. One hundred fifty-one patients (75.9%) had sepsis, and 166 (83.4%) had received prior or were receiving current antimicrobial therapy. Positive stool cultures were obtained from 4/89 (4.5%), and Clostridioides difficile toxin gene tests were positive in 14/188 (7.4%) patients. AP and FA multiplex tests were positive for GI pathogens in 49/199 (24.6%) and 40/199 (20.1%), respectively. The target most frequently detected by AP was Aeromonas spp. Both assays commonly detected enteropathogenic E. coli (EPEC), C. difficile toxin gene, and Salmonella spp.; neither assay detected pathogens in 75.4% and 79.9%. Fever (odds ratio [OR], 2.05; 95% CI, 1.08-3.88; P = .028), watery diarrhea (OR, 2.69; 95% CI, 1.25-5.80; P = .011), and antimicrobial therapy (OR, 2.60; 95% CI, 1.18-5.71; P = .018) were independent factors associated with the negative multiplex test result.

Multiplex GI panel testing effectively detects enteric pathogens associated with diarrhea in hospitalized subjects. The etiology remains undiagnosed in >75% of cases. Factors contributing to negative test results should be considered before implementing the tests.