Etiology and clinical severity of community-acquired acute gastroenteritis in adults at a coastal provincial hospital in Thailand

Acute gastroenteritis (AGE) remains a common cause of illness in tropical regions, but its etiology and predictors of severe disease in adults are incompletely characterized. We conducted a prospective study of adults with community-acquired AGE at Samut Sakhon Hospital, Thailand, from December 2019 to May 2020. Of 534 patients assessed, 266 were included; 161 (60.5%) had severe disease requiring hospitalization and 105 (39.5%) had mild disease managed as outpatients. Among 165 patients who underwent all four diagnostic tests, including stool examination, concentration testing, culture, and viral RT-PCR, an enteropathogen was detected in 49 (29.7%). Detection was similar between severe and mild cases (29.6% vs. 30.0%). Viral pathogens were detected in 10.2% of patients, while parasites were detected in 0.9%. Among patients undergoing stool culture, bacterial pathogens were identified in 15.8%, most commonly Salmonella spp. (6.7%) and Vibrio parahaemolyticus (4.8%). All bacterial isolates were susceptible to ciprofloxacin. Thai nationality, the presence of any comorbidity, history of fever, dehydration, higher diarrhea frequency, higher neutrophil percentage, and lower hematocrit independently predicted severe disease. These findings support early clinical risk stratification and improved diagnostic stewardship to guide targeted treatment and reduce unnecessary antibiotic use in adults with AGE.