Viral and Bacterial Etiology of Acute Febrile Respiratory Syndrome among Patients in Qinghai, China.

Objective This study was conducted to investigate the viral and bacterial etiology and epidemiology of patients with acute febrile respiratory syndrome (AFRS) in Qinghai using a commercial routine multiplex-ligation-nucleic acid amplification test (NAT)-based assay. Methods A total of 445 nasopharyngeal swabs specimens from patients with AFRS were analyzed using the RespiFinderSmart22kit (PathoFinder BV, Netherlands) and the LightCycler 480 real-time PCR system. Results Among the 225 (225/445, 51%) positive specimens, 329 positive pathogens were detected, including 298 (90.58%) viruses and 31 (9%) bacteria. The most commonly detected pathogens were influenza virus (IFV; 37.39%; 123/329), adenovirus (AdV; 17.02%; 56/329), human coronaviruses (HCoVs; 10.94%; 36/329), rhinovirus/enterovirus (RV/EV; 10.03%; 33/329), parainfluenza viruses (PIVs; 8.51%; 28/329), and Mycoplasma pneumoniae (M. pneu; 8.51%; 28/329), respectively. Among the co-infected cases (17.53%; 78/445), IFV/AdV and IFV/M. pneu were the most common co-infections. Most of the respiratory viruses were detected in summer and fall. Conclusion In our study, IFV-A was the most common respiratory pathogen among 22 detected pathogens, followed by AdV, HCoV, RV/EV, PIV, and M. pneu. Bacteria appeared less frequently than viruses, and co-infection was the most common phenomenon among viral pathogens. Pathogens were distributed among different age groups and respiratory viruses were generally active in July, September, and November. Enhanced surveillance and early detection can be useful in the diagnosis, treatment, and prevention of AFRS, as well as for guiding the development of appropriate public health strategies.