Molecular epidemiology of Streptococcus pneumoniae isolated from pediatric community-acquired pneumonia in pre-conjugate vaccine era in Western China

Abstract

Background Streptococcus pneumoniae (S. pneumoniae) is one of the most common pathogens which can cause morbidity and mortality in pediatric infections worldwide. This study aimed to describe the phenotypic and molecular characteristics of community-acquired pneumonia (CAP)-causing S. pneumoniae recovered from children in Western China. Methods We retrospectively enrolled pediatric patients younger than 5 years diagnosed with CAP. All 419 S. pneumoniae isolates were tested for antibiotic susceptibility, serotypes, virulence genes, resistance genes, and sequence types. The potential relationships between molecular characteristics were tested by correspondence analysis. Results Most of S. pneumoniae isolates were resistant to erythromycin, tetracycline, clindamycin and trimethoprim-sulfamethoxazole, with 93.8% isolates classified as multidrug resistant. The dominant STs were ST271 (30.8%) and ST320 (12.2%), while the prevailing serotypes were 19F (46.8%), 6B (11.5%), 23F (9.5%) and 19A (9.3%). The coverage rates of PCV-7 and PCV-13 were 73.03% and 86.16%, while the coverage rates of PCV13 among children aged < 1 year and 1–2 years were high in 93.18% and 93.62%. We also observed that CC271 expressed more of mef (A/E), lytA, rlrA and sipA than non-CC271 isolates. Moreover, there were strong corresponding relationships between molecular characteristics. Conclusions The high coverage rate of PCV13 suggests the necessity of introducing the PCV13 vaccine in Western China. Our findings underscore the value of monitoring multiple molecular characteristics to provide new guidance for developing future pneumococcal vaccines.

Genotypic and phenotypic characteristics of Streptococcus pneumoniae from community-acquired pneumonia patients and healthy asymptomatic participants in Sichuan province, China

“…It is well known that the distribution of S. pneumoniae serotypes changes over age, geographic region, time, and diseases [ 27 , 28 ]. In our study, the most frequent serotypes in CAP carriers group were 3, 19F, 19A, which were similar to other recent studies in China [ 16 , 29 ], however different with serotypes in Italy [ 30 ]. Additionally, the major serotypes from asymptomatic carriers were 3, 6, and 19F in our study, whereas were 19F, 6B, and 6C in Brazil [ 31 ], indicating that serotypes is closely related to geographic region.…”

“…On the other side, we found that serotypes 3 and 19F were frequently found in both asymptomatic carriers and CAP carriers. Indeed, these serotypes are common in asymptomatic carriers and CAP carriers worldwide [ 16 , 33 – 35 ].…”

“…In the pathogenesis of pneumococcal disease, nasopharyngeal colonization is the necessary first step [ 15 ], suggesting that exploration of S. pneumoniae characteristics in asymptomatic carriers is warranted. Although epidemiology studies of S. pneumoniae from patients with CAP and IPD have been conducted in China [ 16 , 17 ], limited data are available for the genotypic characteristics of S. pneumoniae from asymptomatic participants and CAP patients.…”

Molecular Characterization of Predominant Serotypes, Drug Resistance, and Virulence Genes of Streptococcus pneumoniae Isolates From East China

“…Recent epidemiological studies reported the predominant or common serotypes of S. pneumoniae isolates prevailing in the different areas and adjacent countries of China. 19F, 6B, 23F, and 19A were the common serotypes observed among the S. pneumoniae isolates in Western China, while 19F, 19A, and 23F were the predominant serotypes among the S. pneumoniae isolates in North China ( Zhao et al, 2020 ; Liang et al, 2021 ; Zhou et al, 2022 ). In the different areas of Southwest China, 19F and 19A were the predominant pneumococcal serotypes ( Shen et al, 2017 ; Ma et al, 2021 ; Yan et al, 2021 ).…”

“…However, β-lactam antibiotic resistance rates of S. pneumoniae isolates from different areas and countries have a large diversity. For example, PNC and CTX resistance rates among the S. pneumoniae isolates from Western China, North China, and Southwest China were 1.2–79.9% and 0.5–28.6% ( Shen et al, 2017 ; Zhao et al, 2020 ; Liang et al, 2021 ; Yan et al, 2021 ; Zhou et al, 2022 ), while the PNC resistance rates among the S. pneumoniae isolates from East Asia (Japan and South Korea), Southeast Asia (Thailand and Malaysia), India, United States, Europe, and Latin America were 1.7–22.8%, 4–83.1%, 10%, 10.8%, 19.4%, and 68.6%, respectively ( Mendes et al, 2016 ; Yahiaoui et al, 2016 ; Singh et al, 2017 ; Park et al, 2019 ; Moreno et al, 2020 ; Wangirapan et al, 2020 ; Dzaraly et al, 2021 ; Yanagihara et al, 2021 ). In this study, the PNC non-susceptible rate among the 309 S. pneumoniae isolates was as high as 81.6% (63.2% intermediate and 18.4% resistant), but the CTX non-susceptible rate was only 14.2% (11.6% intermediate and 2.6% resistant).…”