Persistent serotype 3 and 19A invasive pneumococcal diseases in adults in vaccine era: Serotype-dependent difference in ceftriaxone susceptibility

Jin Gu Yoon, A. Yeung Jang, Min Ja Kim, Yu Bin Seo, Jacob Lee, Young Hwa Choi, Young Keun Kim, Eun Joo Jeong, Hyun Soo Kim, Ki Tae Kwon, Dong Sik Jung, Won Suk Choi, Jin Soo Lee, Kyung Hwa Park, Hye Won Jeong, Seung hee Baik, Seong Hui Kang, In Gyu Bae, Ji Yun Noh, Hee Jin CheongWoo Joo Kim, Joon Young Song

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Background: Invasive pneumococcal disease (IPD) is associated with substantial morbidity and mortality in children and elderly populations. Serotype distribution and antibiotic susceptibility of IPD isolates are changing with the implementation of pneumococcal vaccination and increasing antibiotic use worldwide. We aimed to determine serotype distribution, antibiogram, and molecular epidemiology of pneumococci in the late stage of PCV13 era. Methods: Prospective multicenter IPD surveillance study was conducted for adults aged ≥ 19 years from July 2019 to June 2021. Clinical and epidemiologic data were collected. In addition, antibiotic susceptibility test, serotype identification and multi-locus sequence typing (MLST) was taken for pneumococcal isolates. Results: A total of 160 IPD cases were collected with mean age of 65.1 years (male, 72.5%). Serotyping was taken for 116 available pneumococcal isolates. PCV13 and PPSV23 serotypes were 32.8% (n = 38) and 56.0% (n = 65), respectively. Serotype 3 (13.8%) and 19A (9.5%) were the most common causative agents of IPD, followed by serogroup 11 (6.9%), 23A (6.9%), 10A (4.3%), and 15B (4.3%). Notably, 32.5% of invasive pneumococcal isolates were non-susceptible to ceftriaxone. Serotypes 11A, 11E and 19A pneumococci showed high ceftriaxone non-susceptible rate (80%, 100% and 81.8% respectively), and they were related to sequence type (ST) 166 and ST320. In comparison, most serotype 3 isolates were ceftriaxone susceptible and related to ST180. Conclusions: PCV serotypes, especially 3 and 19A, are still prevalent in adult IPDs, suggesting that individual PCV13 immunization would be necessary for the elderly people and chronically ill patients. Ceftriaxone non-susceptible rate was remarkably high in invasive pneumococcal isolates.

Original languageEnglish
Pages (from-to)2258-2265
Number of pages8
Issue number15
Publication statusPublished - 2022 Apr 1
Externally publishedYes


  • Multi-locus Sequence Typing
  • Pneumococcal Infections
  • Pneumococcal Vaccines
  • Serotype

ASJC Scopus subject areas

  • Molecular Medicine
  • Immunology and Microbiology(all)
  • veterinary(all)
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases


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