Causes of Lower Respiratory Tract Infections and the Use of Diagnostic Biomarkers in Blood Samples from Children in Hohhot, Inner Mongolia, China, Between July 2019 and June 2020.

BACKGROUND Lower respiratory tract infection (LRTI) in children is due to various pathogens. Appropriate diagnosis and early treatment are important for reducing the mortality rate of LRTI. Data on the epidemiology profiles of LRTI are scarce in northern China. The aim of this study was to provide data on the pathogen pattern of LRTI in hospitalized children in Hohhot, Inner Mongolia, China. MATERIAL AND METHODS From July 2019 to June 2020, nasopharyngeal swabs were collected from 265 children in Hohhot with LRTI, and pathogens were detected with RT-PCR and PCR. The correlations among procalcitonin (PCT), C-reactive protein (CRP), and white blood cells (WBC) with acute respiratory infections were evaluated. RESULTS The highest prevalence of LRTI was detected in 2- to 6-year-old children (149, 56.2%) in winter. Eleven respiratory pathogens were evaluated, and respiratory syncytial virus, Streptococcus pneumoniae and Haemophilus influenza were the most common pathogens in this region. Single viruses, bacteria, mycoplasma, and multiple pathogens were identified in 24.2, 15.8, 5.3, and 54.7% of patients, respectively. The mean blood biomarker values of patients with LRTI were significantly different from those of healthy children. Furthermore, The AUCs were 0.90, 0.74, and 0.84 for bacteria, virus, and mycoplasma PCT values, which were significantly higher than that of WBC and CRP. CONCLUSIONS This evaluation of the regional pattern of pathogens in children with acute respiratory infections and the correlation with blood biomarkers provides valuable information for the prevention and treatment of LRTI in children.