ABSTRSCT Background This study delineated the evolving epidemiology of pneumococcal disease in Taiwan, focusing on emerging serotypes, antimicrobial susceptibility, and genotypes before and after the pandemic. Methods Culture-confirmed pneumococcal disease (CCPD) was analyzed across four Chang Gung Memorial Hospitals in Taiwan in 2019∼2024. Serotypes, multi-locus sequence types, and penicillin and ceftriaxone susceptibility of pneumococcal isolates were determined. Results The incidence of CCPD dropped from 16.09 in 2019 to 5.39 in 2021, followed by a rise to 9.04 in 2024, per 100,000 population. Invasive pneumococcal disease (IPD) accounted for 13.0% (126/969) of CCPD. The most common serotypes for CCPD were 23A (28.4%), 15A (14.2%), 19A (9.5%), and 15B/C (8.7%). Serotype coverage was 24.8% for PCV13, 36.4% for PCV20, and 78.2% for PCV21. Non-PCV13 serotypes contributed to approximately three fourths of CCPD. Penicillin non-susceptibility of non-PCV13 serotypes (59.7%) surpassed that of the PCV13 serotypes (45.7%) in 2024. Penicillin and ceftriaxone non-susceptibility of the isolates from children was higher than that from adults, and such non-susceptibility was more common in isolates from sputum than that from blood. Clonal complex 166 has been emerging as the predominant lineage (27.8%, 269/969), primarily composed of serotypes 23A (85.5%, 230/269) and 11A (6.7%, 18/269). Conclusions The study shows continuously escalating penicillin and ceftriaxone resistance among pneumococcal isolates after the pandemic. Lower β-lactam susceptibility in pediatric upper respiratory tract isolates and adult sputum isolates appear to be derived from the serotype shift for CCPD.
Chen et al. (Fri,) studied this question.