Antimicrobial resistance and molecular epidemiology of Streptococcus pneumoniae in China: a 14‑year serial surveillance study across age groups.

چکیده اصلی

BACKGROUND: Streptococcus pneumoniae poses a significant health threat with rising antimicrobial resistance. In China, long-term, age-stratified data on its molecular epidemiology remain limited. This study investigates resistance trends and serotype distribution across pediatric, adult, and elderly populations over 14 years. METHODS: A total of 1312 clinical isolates collected during seven two‑year surveillance phases (2007-2020) from 24 hospitals across China were analyzed using whole-genome sequencing for serotype prediction, multilocus sequence typing (MLST), and Global Pneumococcal Sequence Clustering (GPSC); antibacterial susceptibility was performed using agar dilution method. RESULTS: Serotypes 19 F and 19 A consistently accounted for the largest proportion of isolates throughout the study period. PCV13 serotype coverage was highest in children (85.8%) and increased nationally from 64.5% to 77.9% over 14 years. MLST identified ST271 and ST320 as the most prevalent clones, often associated with serotypes 19 F and 19 A, respectively. AMR was severe, with > 90% macrolide resistance nationwide. Penicillin non-susceptibility (using non‑meningitis oral breakpoints) increased markedly, especially among pediatric isolates, which also showed higher β-lactam resistance. Fluoroquinolones retained high susceptibility (>97% of isolates susceptible). The resistance gene erm(B) was detected in 96.3% of isolates. CONCLUSION: S. pneumoniae in China exhibits persistent high resistance to macrolides and increasing β-lactam non-susceptibility, particularly in children. Dominant clones and serotypes showed no statistically significant change in proportional trends over the 14 years. PCV13 serotype coverage remains high, yet actual vaccine uptake is low; this suggests a missed opportunity for preventing infections caused by vaccine serotypes, highlighting the potential benefit of increased immunization efforts.

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