Microbial profiles in non-leptospirosis acute undifferentiated febrile illness: Associations with clinical parameters and implications for diagnosis.

BACKGROUND: Acute undifferentiated febrile illness (AUF) remains a challenge in medical diagnosis. This study aimed to investigate the microbial profiles of non-leptospirosis AUF patients from Sisaket province, an endemic region for leptospirosis, and to elucidate their associations with clinical parameters. METHODS: Blood samples from 78 non-leptospirosis AUF patients were confirmed negative for leptospirosis by bacterial culture, lipL32-qPCR, and the microscopic agglutination test. 16S rDNA and ITS sequencing were used to identify bacterial and fungal communities. Patients were categorized into Only Bacteria (OB), Only Fungi (OF), and Both Bacteria and Fungi (BBF) groups. Microbial differences were assessed using Principal Coordinate Analysis (PCoA) and associations with clinical variables analyzed using Generalized Linear Models (GLM). RESULTS: Stenotrophomonas emerged as the predominant bacterial genus in both OB and BBF groups, while Aspergillus and Candida dominated the fungal profiles in OF and BBF groups. Bacterial compositions differed significantly between OB and BBF groups (P = 0.002), indicating that concurrent bacterial-fungal presence alters bacterial community structure, whereas fungal profiles remained stable. GLM analysis revealed significant associations between specific microbial taxa and clinical parameters, including blood pressure, temperature, hematological indices, and liver function tests. CONCLUSION: Our study sheds light on the microbial landscape in non-leptospirosis AUF patients, establishing connections with clinical parameters. This holistic approach enriches our understanding of AUF's etiology, presenting avenues for targeted diagnostic and therapeutic strategies in systemic infections.