Characteristics of Streptococcus pneumoniae colonising Cypriot children during a period of high PCV10 and PCV13 vaccine coverage: serotypes and antimicrobial resistance
摘要
Nasopharyngeal carriage of Streptococcus pneumoniae is a key factor for transmission, invasive disease, and antimicrobial resistance. Data on pneumococcal carriage in children in Cypriot are limited.
MethodsWe conducted a cross sectional study from December 2023 to May 2024, during a period of high PCV10 and PCV13 vaccine coverage in Cyprus, including children aged six months to six years who attended outpatient clinics in Cyprus. Nasopharyngeal swabs were cultured, and Streptococcus pneumoniae isolates were identified using conventional methods and confirmed by polymerase chain reaction. Serotyping was performed using multiplex polymerase chain reaction, latex agglutination, and whole-genome sequencing when needed. Antimicrobial susceptibility was assessed according to European guidelines. Logistic regression was used to identify risk factors for carriage.
ResultsA total of 809 children were included, 83.85% of whom were fully vaccinated with pneumococcal conjugate vaccines. The overall prevalence of carriage was 35.72%. Recent antibiotic use (OR 1.47, 95% CI 1.03–2.12) and daycare attendance (OR 1.89, 95% CI 1.37–2.63) were associated with increased carriage, whereas receipt of at least one vaccine dose was protective (OR 0.38, 95% CI 0.17–0.82). Among the 290 isolates, 34 distinct serotypes were identified, predominantly non-vaccine types including 15B, 23A, 23B, 24, 6C, and 15A. Most isolates (68%) were not covered by available vaccines. Resistance was highest for erythromycin (54.32%), tetracycline (37.28%), and clindamycin (31.65%). Multidrug resistance occurred in 28.94% of the isolates, mainly in serotypes 24, 15A, and 19A.
ConclusionsDespite extensive vaccination, pneumococcal carriage in Cypriot children remains high, with predominance of non-vaccine serotypes and substantial antimicrobial resistance. Continuous surveillance is essential to guide vaccination and antimicrobial stewardship.