Molecular characteristics of macrolide-resistant Mycoplasma pneumoniae in children with community-acquired pneumonia in Urumqi, Xinjiang, China in autumn, winter, and spring 2023–2024

Following the COVID-19 pandemic, the resurgence of Mycoplasma pneumoniae (MP) infections among children in China has raised urgent concerns regarding antimicrobial drug resistance. We reveal the molecular characteristics of macrolide-resistant MP (MRMP) in children with community-acquired pneumonia (CAP) in autumn, winter, and spring 2023-2024 in Urumqi, Xinjiang, China. Throat samples were collected from 1446 children hospitalized for CAP between October 2023 and April 2024. The polymerase chain reaction fluorescent probe method was used to detect respiratory pathogens, and clinical data from the children were collected. Throat swab samples with positive MP nucleic acid test results were subjected to MP-23S rRNA gene sequencing, P1 genotyping, multilocus sequence typing, and 16S rRNA evolution analyses. The overall positive rate for MP was 32.2 %. Among these cases, 88 % exhibited MP infection exclusively, while 12 % demonstrated mixed MP infections, with double infections being the most prevalent type of co-infection. Children aged 7-12 years had the highest infection rate, reaching 42.2 % (P < 0.05). The prevalence of macrolide-resistance mutations in MP was 99.1 %, which was predominantly due to the A2063G mutation (98.2 %). The dominant P1 genotype was P1-I (91.5 %), with a resistance mutation rate of 100 %. ST-3 was the dominant MP strain. Evolutionary analysis of 16S rRNA showed that all predominant MP strains belonged to the same evolutionary branch. The MP infection rate in children with CAP showed a significant upward trend from autumn 2023 and remained at a high level until spring 2024. During this period, the infection rate of MRMP, mainly P1-I and ST-3 types, was high. Additionally, we identified 4 MP strains classified as type P1-II, all of which belonged to CC2, and 85 MP strains were categorized as type P1-I, all belonging to CC1. This study reveals that the MRMP epidemic was driven by near-universal macrolide-related mutations associated with clonal ST-3/P1-I strains. Our findings underscore the necessity of implementing real-time molecular surveillance and establishing treatment guidelines in post-pandemic settings.