OBJECTIVE  To analyze the clinical characteristics and risk factors of Mycoplasma-associated plastic bronchitis (M-PB), providing references for clinical treatment.

METHODS  The etiology and drug resistance of children with PB and severe pneumonia admitted to the pediatric department of Dongguan Maternal and Child Health Care Hospital from Sep. 2022 to Dec. 2024 were collected. Meanwhile, a comparative analysis was conducted on various indicators between M-PB and non-plastic severe Mycoplasma pneumonia. Indicators with statistically significant differences were used as independent variables, with M-PB as the dependent variable. Multivariate regression analysis was employed to identify risk factors associated with M-PB, and a receiver operating characteristic (ROC) curve was plotted to assess its feasibility.

RESULTS  Among the 102 cases in the M-PB group, 9 were sensitive to macrolides, while 93 cases (91.18%) with resistant to macrolides. In the 194 cases of non-plastic severe Mycoplasma pneumonia, 14 were sensitive to macrolides and 180 cases (92.78%) resistant. There was no statistically significant difference in fever duration, hospital stay and prognosis between the azithromycin treatment group (children under 8 years old) and the doxycycline treatment group (children over 8 years old). Among M-PB patients, 9 cases experienced more than three respiratory tract infections within 6 to 12 months after discharge, and 5 had a history of rhinitis or allergies. The age, fever duration, hospital stay, neutrophil-to-lymphocyte ratio, lactate dehydrogenase, serum ferritin, C-reactive protein and D-dimer levels were all higher in the M-PB group than those in the non-plastic severe Mycoplasma pneumonia group (P＜0.05). Fever duration (OR=1.501, 95%CI: 1.196–1.885, P＜0.001) was identified as a risk factor for PB. The area under the curve for predicting M-PB with a fever duration＞9.50 days was 0.752 (95%CI: 0.667–0.838, P＜0.001), with an optimal cutoff value of 9.50 days.

CONCLUSIONS  The main pathogen of PB is Mycoplasma, mostly were macrolide-resistant. The prognosis is similar between the azithromycin group (children under 8 years old) and the doxycycline group (children over 8 years old). Patients with M-PB exhibit stronger inflammatory responses than those with non-plastic severe Mycoplasma pneumonia, with elevated levels of various inflammatory factors and significantly prolonged fever duration. Fever duration＞9.50 days is a risk factor for M-PB. Patients who experience recurrent respiratory infections after discharge often have a history of rhinitis and/or allergies, necessitating the management of rhinitis and avoidance of allergens.