Abstract:

Objective To investigate the application of combined determination of inflammatory markers in acute respiratory tract infections，and to provide a reference for clinical prevention and rational diagnosis and treatment. Methods A total of 122 560 patients with acute respiratory tract infections in Shanghai Songjiang Jiuting Hospital from February 2023 to January 2024 were enrolled. They were classified into ≤3，4-6，7-11，12-14 and >14 years old groups. IgM antibodies against Mycoplasma pneumoniae（MP），Chlamydia pneumoniae（CP），respiratory syncytial virus（RSV），adenovirus（ADV），group B coxsackie virus（COXB），influenza A virus （IFVA） and influenza B virus （IFVB） were determined. Totally，300 patients with acute respiratory tract infections in the same period in Shanghai Songjiang Jiuting Hospital were enrolled. The positive status of pathogens was determined by polymerase chain reaction-fluorescence probe method，and the patients were classified into MP infection group（100 cases，MP positive），viral infection group（100 cases，IFVA or IFVB positive）and bacterial infection group（100 cases）. Another 80 healthy subjects from Shanghai Songjiang Jiuting Hospital during the same period were enrolled as healthy control group. Blood routine test，interleukin-6（IL-6），procalcitonin（PCT），C-reactive protein（CRP）and neutrophil-to-lymphocyte ratio（NLR）were performed，determined and calculated. Receiver operating characteristic（ROC）curve was used to evaluate the efficacy of each indicator in differentiating different pathogen infections. Results The total positive rates of pathogens in the≤3，4-6，7-11，12-14 and >14 years old groups were 17.75%，24.48%，22.70%，19.20% and 15.91%，respectively. There was statistical significance in the positive rates of MP IgM antibodies among different age groups （P<0.05），and they were gradually decreased with the increase of ages. The positive rate of MP IgM antibody in≤3 years old group was higher than that of other pathogens（P<0.05），and the positive rates of MP and IFVA in 7-11 years old group were higher than those in other age groups（P<0.05）. The bacterial infection group，viral infection group and MP infection group，except for NLR（P>0.05），had higher indicators[white blood cell（WBC）count，CRP，PCT，IL-6]than healthy control group （P<0.05）. The areas under curves（AUC）of the combined determination of PCT，CRP，WBC count and IL-6 for differentiating between bacterial infection and viral infection，bacterial infection and MP infection，and viral infection and MP infection were 0.887，0.856 and 0.658，respectively. Conclusions The combined determination of inflammatory indicators has certain clinical value in the differential diagnosis of bacterial infections and viral infections，as well as Mycoplasma infections. Combined with pathogen determination，it can enhance the efficiency of early differential diagnosis of acute respiratory tract infections in children.

Key words: Inflammatory marker, Mycoplasma pneumoniae, Influenza A virus, Influenza B virus, Acute respiratory tract infection