Serotype distribution of <i>Streptococcus pneumoniae</i> in children with invasive diseases in Türkiye, 2019–2025: An update in the 10th to 15th years of routine pneumococcal conjugate vaccination

isolates from sterile sites (blood, cerebrospinal fluid, pleural fluid) were confirmed by standard methods and serotyped using the Quellung reaction. Antimicrobial susceptibility was determined by gradient test as per CLSI criteria. A total of 203 samples were identified from 203 pediatric cases (median age 4 y, 56.2% boys). The clinical presentations were bacteremia/sepsis (57.6%) and meningitis (26.1%). The leading serotypes were 3 (14.3%), 14 (10.3%), 19F (7.9%), 19A (6.4%), 9N (4.4%), 15A (4.4%). PCV13 serotypes accounted for 46.8% isolates, while PCV7 and PCV10 serotypes were detected in 23.2% and 24.6%, respectively. Broader vaccines would increase coverage: PCV15 (46.8%) and PCV20 (56.7%). Antibiotic susceptibility (non-meningitis breakpoint) remained high for beta-lactams; 91.9% of isolates were penicillin-susceptible, with only 0.7% fully resistant, and cefotaxime resistance was rare (2.7%). Conversely, macrolide resistance was high, with 60.2% of isolates resistant to erythromycin. A decade after PCV13 implementation, vaccine serotypes - particularly 3, 14, 19F, and 19A - still cause nearly half of pediatric IPD, though non-vaccine serotypes such as 9N and 15A are rising. Higher-valent PCVs may improve protection, and continued surveillance is critical to guide vaccine policy and treatment strategies.

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Publication Details

Journal
Human Vaccines & Immunotherapeutics
Published
2026-04-06
DOI
https://doi.org/10.1080/21645515.2026.2650946
Primary Topic
Pneumonia and Respiratory Infections
Type
article
Field-Weighted Citation Impact
0.00

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article

Serotype distribution of Streptococcus pneumoniae in children with invasive diseases in Türkiye, 2019–2025: An update in the 10th to 15th years of routine pneumococcal conjugate vaccination

BO Baysan, Asuman Bırıncı, Yücel Duman, Özlem Koyuncu Özyurt et al.
Human Vaccines & Immunotherapeutics
Pneumonia and Respiratory Infections
article

Serotype distribution of Streptococcus pneumoniae in children with invasive diseases in Türkiye, 2019–2025: An update in the 10th to 15th years of routine pneumococcal conjugate vaccination

BO Baysan, Asuman Bırıncı, Yücel Duman, Özlem Koyuncu Özyurt, Ufuk Hasdemir, Esra Özkaya, Nisel Yılmaz, Duygu Öcal, Soner Sertan Kara, Ener Çağrı Dinleyici, Akgün Yaman, Lütfiye Öksüz, Cüneyt Özakın, Yelda Sorguç, Gülşen Hasçelik, Zeynep Çizmeci, Şöhret Aydemir, Eda KARADAĞ ÖNCEL, Özgen Alpay Özbek, Fatma Nur Öz, Melike Emiroglu, Candan Öztürk, Gülşen Hazırolan, Faruk Aydın, Hüseyin Güdücüoğlu, İlker Devrim, Deniz Bahar Akgün Karapınar, Hakan Uslu, Yasemin Ay Altıntop, Adem Karbuz, Mehmet Ceyhan, Yasemin Zer
article en

Abstract

isolates from sterile sites (blood, cerebrospinal fluid, pleural fluid) were confirmed by standard methods and serotyped using the Quellung reaction. Antimicrobial susceptibility was determined by gradient test as per CLSI criteria. A total of 203 samples were identified from 203 pediatric cases (median age 4 y, 56.2% boys). The clinical presentations were bacteremia/sepsis (57.6%) and meningitis (26.1%). The leading serotypes were 3 (14.3%), 14 (10.3%), 19F (7.9%), 19A (6.4%), 9N (4.4%), 15A (4.4%). PCV13 serotypes accounted for 46.8% isolates, while PCV7 and PCV10 serotypes were detected in 23.2% and 24.6%, respectively. Broader vaccines would increase coverage: PCV15 (46.8%) and PCV20 (56.7%). Antibiotic susceptibility (non-meningitis breakpoint) remained high for beta-lactams; 91.9% of isolates were penicillin-susceptible, with only 0.7% fully resistant, and cefotaxime resistance was rare (2.7%). Conversely, macrolide resistance was high, with 60.2% of isolates resistant to erythromycin. A decade after PCV13 implementation, vaccine serotypes - particularly 3, 14, 19F, and 19A - still cause nearly half of pediatric IPD, though non-vaccine serotypes such as 9N and 15A are rising. Higher-valent PCVs may improve protection, and continued surveillance is critical to guide vaccine policy and treatment strategies.

Human Vaccines & ImmunotherapeuticsVol. 22(1)
Dicle University (TR), Trakya University (TR), University of Medicine Tirana (AL), Ministry of Health (TR), Bursa Uludağ Üni̇versi̇tesi̇ (TR), Izmir University (TR), Infectious Disease Research Institute (US), Selçuk University (TR), Ankara University (TR), Karadeniz Technical University (TR), University of Health Science (KH), Dokuz Eylül University (TR), Akdeniz University (TR), Inonu University (TR), Ondokuz Mayıs University (TR), Ege University (TR), Dr. Behçet Uz Çocuk Hastalıkları Hastanesi (TR), International Clinic of Rehabilitation (UA), Infectious Disease Consultants (US), Office of Infectious Diseases (US), Sağlık Hizmetleri Uygulama ve Araştırma Hastanesi (TR), Izmir Tepecik Eğitim ve Araştırma Hastanesi (TR), Muslim Community Center Medical Clinic (US), Pediatric Infectious Diseases Society (US), Atlas Üniversitesi, Istanbul Arel University (TR), Eskişehir Osmangazi University (TR), Mersin Üniversitesi (TR), Cukurova University (TR), Gaziantep University (TR), Atatürk University (TR), Hacettepe University (TR), Istanbul University (TR), Marmara University (TR), Adnan Menderes University (TR), University of Health Sciences Antigua (AG)
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Good health and well-being
Openalex Percentile: Top 29%
Pneumonia and Respiratory Infections
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