Clinical and laboratory features of pediatric Mycoplasma pneumoniae Pneumonia with viral versus bacterial co-infection

To analyse the epidemiological, clinical, and laboratory differences among children, in Suzhou, with Mycoplasma pneumoniae (MP) mixed with viral or bacterial pneumonia and to provide evidence for early clinical differentiation and localised prevention. This retrospective study included 392 children with Mycoplasma pneumoniae pneumonia (MPP) who were divided into an MPP mixed with viral pneumonia group ( n = 254) and a bacterial pneumonia group ( n = 138). Epidemiological characteristics, clinical manifestations, immune, coagulation, and inflammatory indicators, pathogen distribution, and bacterial drug susceptibility were compared. The MPP mixed with viral pneumonia group had older children [6 (3, 8) vs. 4 (2, 6.25) years, P = 0.001], a higher incidence of pneumonia in spring (51.97% vs. 18.12%, P < 0.001), and more crackles and fewer breath sounds ( P < 0.05). The MPP mixed with bacterial group was more common in the summer and autumn, with a higher vomiting incidence ( P = 0.021), higher C3 abnormal rate ( P = 0.049) and greater procalcitonin elevation ( P < 0.001). The MPP mixed with viral pneumonia group had higher level of serum amyloid A and D-dimer ( P < 0.05). Human rhinovirus was the predominant virus (53.67%), and Streptococcus pneumoniae was the main bacterium (58.99%) with 100% Erythromycin resistance but high sensitivity to Penicillin G and Cefotaxime. The two groups differed in age, season, clinical features, and several biomarkers. Viral coinfection was associated with higher SAA and D-dimer, while bacterial coinfection with higher PCT. However, the discriminatory value of these markers is limited, and they should be used in conjunction with other clinical data. Local pathogens were dominated by rhinovirus and S. pneumoniae , with the latter exhibiting complete erythromycin resistance, highlighting the need for surveillance and rational antibiotic use.