OBJECTIVE To understand the clinical characteristics of patients with Mycoplasma pneumoniae (MP) infection, and to explore the related factors of mixed infection, to provide theoretical support for the diagnosis and treatment of MP infection.

METHODS The clinical data of patients diagnosed with MP infection in the 305th hospital of PLA from Dec. 2023 to Apr. 2024 were collected, and the clinical characteristics of patients infected with MP were analyzed. Additionally, the impacts of MP mixed infections with other pathogens on the severity of the disease were compared, while the relevant influencing factors of MP mixed with other pathogens were analyzed by the logistic regression model.

RESULTS A total of 114 patients with MP infection were collected, both genders had 57 cases (50.00%, respectively), 60 (52.63%) were adults, 73 (64.04%) had simple MP infection and 41 (35.96%) had mixed infection. The clinical manifestations of MP infection primarily included fever and cough, with most fevers being low to medium intensity. Additionally, the biochemical indexes were predominantly within normal ranges, however, the interleukin 6 (IL-6) level was relatively high. The abnormalities of chest X-ray examination accounted for 84.21% of the cases. In mixed infection cases, fever, dizziness, fatigue, headache and muscle pain were more prevalent than single MP infection cases (P < 0.05), and CRP level elevated in the mixed infection group (P=0.001), whereas white blood cell level and lymphocyte count decreased compared to the single MP infection group (P < 0.05). Multivariate logistic regression analysis showed that fever (OR=4.112, 95%CI: 1.046-16.161) and above 46 years old (OR=8.555, 95%CI: 1.394-52.493) were the relevant influencing factors for MP mixed with other pathogens infection.

CONCLUSION Clinical features of MP-infected patients are atypical, but IL-6 levels are relatively high. MP is often mixed with viral infections, and fever and above 46 years old are the risk factors for mixed MP infection.