Antimicrobial susceptibility and molecular characteristics of Mycoplasma pneumoniae isolates from Children in Xi'an regions of China

Chao Huang¹Jun Yang²Jia Cao¹Haiyan Ren¹Nan Gao^2*Jianjun Liu^1,2*

• ¹Xi'an International Medical Center Hospital, Xi’an, China
• ²Xi'an Gaoxin Hospital, Xi'an, China

This study investigates the molecular epidemiology and antimicrobial resistance patterns of Mycoplasma pneumoniae (MP) in pediatric patients from Xi'an, China, collected in 2023. This study examined the recent genetic traits and antimicrobial drug sensitivity characteristics of Mycoplasma pneumoniae in children in Xi'an, offering valuable clinical insights for the management of Mycoplasma pneumoniae infection in pediatric patients in Xi'an. A total of 376 hospitalized children diagnosed with Mycoplasma pneumoniae (MP) infection, exhibiting respiratory symptoms such as fever and cough, were enrolled in the study conducted at our hospital from January 2023 to December 2023. The study sought to explore Mycoplasma pneumoniae infection, genetic analysis, and drug resistance through the utilization of Mycoplasma pneumoniae in vitro culture drug susceptibility testing, and MALDI-TOF MS detection. Among the 376 children clinically diagnosed with Mycoplasma pneumoniae pneumonia, drug susceptibility tests were conducted on 70 cases, revealing a high resistance of the bacteria to macrolide drugs. Through method analysis using MALDI-TOF mass spectrometry, it was found that the prevalent Mycoplasma pneumoniae strains in Xi'an were predominantly P1-I (68/70), with all strains exhibiting the A→G mutation at position 2063, the A→T mutation at position 2064,and the A→C mutation at position 2617. Remarkably, all isolates harbored simultaneous mutations at positions A2063G, A2064G, and A2617C in the 23S rRNA gene, confirmed by Sanger sequencing, an uncommon triple mutation pattern associated with macrolide resistance. Despite universal genotypic mutations, phenotypic resistance to macrolides was observed in only 39% of isolates, highlighting a notable genotype-phenotype discordance. High resistance rates to fluoroquinolones (20–30%) and tetracyclines (8.6–30%) were also observed. Given the continued rise of antibiotic-resistant MP globally, our findings emphasize the need for ongoing regional surveillance and reconsideration of treatment guidelines. We recommend future studies to employ whole-genome sequencing to confirm and clarify resistance mechanisms comprehensively.