Serotype distribution and antimicrobial resistance in pediatric invasive pneumococcal pneumonia: A Laboratory Surveillance Study from Argentina, 2022-2024.
Source: PubMed, NCBI / U.S. National Library of Medicine
Streptococcus pneumoniae remains a leading global cause of pediatric morbidity and mortality, with evolving serotype distributions following vaccine introductions. This national surveillance study characterizes the contemporary epidemiology of invasive pneumococcal pneumonia (IPP) among Argentine children under 11 years (2022-2024). We analyzed 316 invasive pneumonia isolates from 78 pediatric hospitals across 24 jurisdictions, obtained through Argentina's National IPD Surveillance System. Serotyping (Quellung reaction) and antimicrobial susceptibility testing (CLSI agar dilution) were performed. Isolates were stratified by age (<2, 2-5, 6-10 years) and clinical presentation. The surveillance showed persistent dominance of vaccine-type serotypes 3 (22.1 %), 19A (12.0 %), and 14 (6.3 %), alongside emerging non-vaccine type 12F (6.7 %). Distinct age-specific patterns emerged, with serotypes 7F and 1 predominating in 6-10 years and 24A exclusively detected in infants. Serotypes 3 and 19A demonstrated a significant association with pleural effusion, while serotype 24B was the dominant variant in non-effusion invasive pneumonia cases. Antimicrobial susceptibility testing revealed high susceptibility to β-lactams, with 94 % of isolates susceptible to penicillin and amoxicillin. However, a concerning 24.3 % rate of multidrug resistance was observed, primarily concentrated in serotypes 19A and 24F/A/B. Our analysis breaks significant shifts in pneu
Abstract
Streptococcus pneumoniae remains a leading global cause of pediatric morbidity and mortality, with evolving serotype distributions following vaccine introductions. This national surveillance study characterizes the contemporary epidemiology of invasive pneumococcal pneumonia (IPP) among Argentine children under 11 years (2022-2024). We analyzed 316 invasive pneumonia isolates from 78 pediatric hospitals across 24 jurisdictions, obtained through Argentina's National IPD Surveillance System. Serotyping (Quellung reaction) and antimicrobial susceptibility testing (CLSI agar dilution) were performed. Isolates were stratified by age (<2, 2-5, 6-10 years) and clinical presentation. The surveillance showed persistent dominance of vaccine-type serotypes 3 (22.1 %), 19A (12.0 %), and 14 (6.3 %), alongside emerging non-vaccine type 12F (6.7 %). Distinct age-specific patterns emerged, with serotypes 7F and 1 predominating in 6-10 years and 24A exclusively detected in infants. Serotypes 3 and 19A demonstrated a significant association with pleural effusion, while serotype 24B was the dominant variant in non-effusion invasive pneumonia cases. Antimicrobial susceptibility testing revealed high susceptibility to β-lactams, with 94 % of isolates susceptible to penicillin and amoxicillin. However, a concerning 24.3 % rate of multidrug resistance was observed, primarily concentrated in serotypes 19A and 24F/A/B. Our analysis breaks significant shifts in pneumococcal serotype epidemiology following PCV13 implementation, with three key patterns emerging: (1) persistent circulation of vaccine-type serotypes 3 and 19A, (2) emergence of non-vaccine type particularly 12F and 24B, and (3) dynamic fluctuations in serotype distribution suggesting ongoing selective pressure. These evolving epidemiological patterns, coupled with concerning multidrug resistance in key serotypes 19A and 24F/A/B, underscore two critical needs: enhanced national surveillance systems to monitor serotype replacement, and the evaluation of next-generation vaccines that provide broader coverage against both persistent vaccine-types and emerging non-vaccine types.