Pneumococcal Carriage, Serotypes, and Antibiotic Resistance in Malaysian Children: A Multi-Centre Study

The goal of this observational study is to determine the prevalence, serotype distribution, and antimicrobial resistance patterns of nasopharyngeal carriage of Streptococcus pneumoniae in Malaysian children aged ≤5 years following the implementation of pneumococcal conjugate vaccines (PCVs). The study focuses on healthy and mildly symptomatic male and female children aged 0-60 months recruited from urban and semi-urban settings in Kuala Lumpur, Selangor, and Negeri Sembilan. The main questions it aims to answer are: 1. What is the overall and age-specific prevalence of nasopharyngeal pneumococcal carriage among children aged ≤5 years in Malaysia? 2. What are the circulating serotypes and antimicrobial resistance (AMR) profiles of pneumococcal isolates, and how are they associated with vaccination status and PCV valency coverage? Researchers will compare carriage prevalence, serotype distribution (vaccine-type vs non-vaccine-type), and antimicrobial resistance patterns across different states, vaccination statuses, and socioeconomic backgrounds to determine differences in transmission dynamics and potential serotype replacement patterns. Participants will: 1. Undergo a nasopharyngeal swab collection for pneumococcal detection. 2. Provide demographic and vaccination history information through a standardised case report form completed with parental/guardian consent. 3. Have their samples analysed using bacterial culture, antimicrobial susceptibility testing, and whole-genome sequencing (WGS) for serotyping and resistance profiling.