Journal Article

Distribution of serotypes and antibiotic resistance profiles of Streptococcus pneumoniae in hospitalized adult patients: aretrospective multicenter surveillance in China (2018–2019)

Zhang, Feifei, Zhao, Chunjiang, Yang, Shuo, Chen, Hongbin, Wang, Hui, Wang, Zhanwei

2025

Overview

Background Streptococcus pneumoniae ( S. pneumoniae ) remains a major cause of community acquired pneumonia (CAP), particularly among older adults. In China, pneumococcal infections pose a substantial disease burden, with rising antibiotic resistance. Although vaccines have effectively reduced disease worldwide, data on adult serotype distribution and resistance in China are scarce. This study investigates serotype patterns and antimicrobial susceptibility of S. pneumoniae among Chinese adults. Methods We collected a total of 474 S. pneumoniae isolates from adult patients diagnosed with pneumococcal infections in 14 cities across five geographic regions of China between 2018 and 2019. Clinical specimens included sputum, blood, bronchoalveolar lavage fluid (BALF), cerebrospinal fluid (CSF), pharyngeal and nasal swabs, and middle ear fluid. Minimum inhibitory concentrations (MICs) of antimicrobial agents were determined using the agar dilution method. Pneumococcal serotyping was performed using the Pneumotest-Latex kit and type-specific antisera. Results Serotype 19F was the most prevalent across all age groups, specimen types, and regions. 20-valent pneumococcal conjugate vaccine (PCV20) is expected to provide the highest serotype coverage (69.4%) among all vaccines evaluated. Multidrug resistance was detected in over 94% of isolates, with high resistance to macrolides, tetracycline, and clindamycin. β-lactam resistance varied by syndrome and region. Non-invasive isolates showed slightly higher resistance than invasive ones. Serotypes covered by higher-valency vaccines were more likely to be antibiotic-resistant, although fluoroquinolone and vancomycin resistance remained low. Conclusions Our findings highlight a high burden of antimicrobial resistance and predominance of specific serotypes, particularly 19F, among adult S. pneumoniae isolates in China. The broad serotype coverage of PCV20 suggests its potential advantage in future adult immunization strategies. Continued surveillance of serotype distribution and resistance patterns is essential to inform vaccine policy and guide effective antibiotic use.

• Publisher: BioMed Central,Springer Nature B.V,BMC
• Subject: Adolescent / Adult / Adults / Age groups / Aged / Aged, 80 and over / Amides / Anti-Bacterial Agents - pharmacology / Antibiotic resistance / Antibiotics / Antimicrobial agents / Antimicrobial resistance / Antisera / Bacteria / Bronchus / Cerebrospinal fluid / China / China - epidemiology / Clindamycin / Dilution / Drug Resistance, Bacterial / Drug Resistance, Multiple, Bacterial / Ear diseases / Female / High resistance / Hospitalization / Hospitals / Humans / Immunization / Infectious disease and antibiotic resistance epidemiology / Infectious Diseases / Internal Medicine / Latex / Lavage / Male / Medical Microbiology / Medicine / Medicine & Public Health / Meningitis / Microbial Sensitivity Tests / Middle Aged / Middle ear / Mortality / Multidrug resistance / Multidrug resistant organisms / Older people / Parasitology / Pediatrics / Penicillin / Pneumococcal conjunctive vaccine / Pneumococcal Infections - epidemiology / Pneumococcal Infections - microbiology / Pneumococcal Vaccines / Pneumonia / Regulatory approval / Retrospective Studies / Serogroup / Serotype / Serotypes / Serotyping / Sputum / Streptococcus infections / Streptococcus pneumoniae / Streptococcus pneumoniae - classification / Streptococcus pneumoniae - drug effects / Streptococcus pneumoniae - isolation & purification / Surveillance / Tropical Medicine / Vaccines / Valency / Vancomycin / Young Adult / β-Lactam antibiotics