[Epidemiological characteristics of co-infection with drug-resistant Mycoplasma pneumoniae and non-bacterial pathogens in a children's hospital in Ningbo City from 2021 to 2024].

To investigate the epidemiological characteristics of co-infection involving macrolide-resistant Mycoplasma pneumoniae (MRMP) and non-bacterial pathogens in hospitalized children at Women and Children's Hospital of Ningbo University from 2021 to 2024, a retrospective cross-sectional study was conducted. Throat swabs were collected from children admitted for respiratory tract infections between January 2021 and December 2024. A total of 22 311 children aged 0-18 years old were included, including 12 021 males and 10 290 females. The median age was 5.00 years and the mean age was (5.02±3.25) years. Real-time fluorescence quantitative polymerase chain reaction (PCR) and multiplex PCR were employed to determine the MP infection rate, the prevalence of MRMP, and the co-infection rates with non-bacterial pathogens across different years. Patients with MRMP were categorized into two groups based on the presence or absence of co-infections: simple infection group and mixed infection group. The differences in age, gender, and onset time between these groups were analyzed, along with the distribution of pathogens in the mixed infection group. Chi-square tests were used for intergroup comparisons. The results showed that the overall positive rate of MP among the 22 311 children was 39.42% (8 794/22 311), with a detection rate of MP drug resistance gene mutations at 70.42% (6 193/8 794). The co-infection rate of MRMP was 24.29% (1 504/6 193). Statistically significant differences were observed in the MP positive rate and the detection rate of drug resistance gene mutations from 2021 to 2024 (²=1 674.420, <0.05; ²=67.733, <0.05), with peak values in 2023 (50.87% and 73.83%, respectively). Among the annual co-infections, the highest rate was in 2024 (28.72%), while the lowest was in 2022 (7.30%). In the age distribution, the rate of mixed infections decreased with increasing age (=84.742, <0.05). Seasonally, the infection rates in winter 2023 and the spring, summer, and autumn of 2024 were significantly higher than those in 2022 (=24.243, 13.101, 26.181, and 10.687, respectively; all <0.05), with the lowest mixed infection rate observed in winter 2022 over the four-year period. Over the four years, the highest positive rate for rhinovirus was consistently observed in MRMP co-infections each year, particularly in the 3-to 6-year-old age group. The positive rate for mixed infections involving respiratory syncytial virus, human bocavirus, and parainfluenza virus was notably higher in the 0- to 3-year-old age group. Following the removal of non-pharmaceutical interventions (NPIs) in December 2022, the co-infection rate of other respiratory viruses and MRMP increased in Ningbo City. In conclusion, the positive rate of MRMP has shown an upward trend from 2021 to 2023. Post-NPI removal, MRMP mixed infections have become more prevalent in 2023 and 2024, predominantly affecting children aged 0-6 years, with rhinovirus being the most common co-pathogen.