TY - JOUR
T1 - Age influences the emm type distribution of pediatric group A streptococcal pharyngeal isolates
AU - Jaggi, Preeti
AU - Tanz, Robert R.
AU - Beall, Bernard
AU - Shulman, Stanford T.
N1 - Funding Information:
Supported by a grant from IDBiomedical.
PY - 2005/12
Y1 - 2005/12
N2 - Background: emm types 12, 1, 28, 3, 4, 2 and 6 (in that order) are the types most commonly associated with uncomplicated group A streptococcal (GAS) pharyngitis in the United States, together accounting for ∼78% of isolates. Objective: To determine whether the distribution of common pharyngeal group A streptococcal GAS types differs at various ages throughout childhood. Study Design: We emm typed 3356 GAS isolates collected from the United States and Canada during 3 streptococcal seasons (2000-2003). Variations in prevalence by age for the 7 most prevalent emm types and the "uncommon" category (all types accounting for <5% of the total number of isolates) were analyzed and assessed for significance by χ2. Results: The proportion of uncommon isolates increased significantly with increasing age from 18% in group 1 to 37% in group 4 (P = 0.001). We found a significant decrease in the proportion of the common pharyngeal emm types, specifically emm 12 and emm 4 type isolates, with increasing age (P = 0.001 and P = 0.003, respectively); there was no significant decline in the prevalence of other common pharyngeal types (emm 1, 2, 3, 6 and 28) with increasing age. Conclusion: Age-related changes in emm type distribution of pharyngeal GAS are present in childhood; these changes may reflect acquisition of immunity to more common types as a consequence of exposure early in life, but this remains to be demonstrated.
AB - Background: emm types 12, 1, 28, 3, 4, 2 and 6 (in that order) are the types most commonly associated with uncomplicated group A streptococcal (GAS) pharyngitis in the United States, together accounting for ∼78% of isolates. Objective: To determine whether the distribution of common pharyngeal group A streptococcal GAS types differs at various ages throughout childhood. Study Design: We emm typed 3356 GAS isolates collected from the United States and Canada during 3 streptococcal seasons (2000-2003). Variations in prevalence by age for the 7 most prevalent emm types and the "uncommon" category (all types accounting for <5% of the total number of isolates) were analyzed and assessed for significance by χ2. Results: The proportion of uncommon isolates increased significantly with increasing age from 18% in group 1 to 37% in group 4 (P = 0.001). We found a significant decrease in the proportion of the common pharyngeal emm types, specifically emm 12 and emm 4 type isolates, with increasing age (P = 0.001 and P = 0.003, respectively); there was no significant decline in the prevalence of other common pharyngeal types (emm 1, 2, 3, 6 and 28) with increasing age. Conclusion: Age-related changes in emm type distribution of pharyngeal GAS are present in childhood; these changes may reflect acquisition of immunity to more common types as a consequence of exposure early in life, but this remains to be demonstrated.
KW - Children
KW - M type
KW - Streptococcus pyogenes
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U2 - 10.1097/01.inf.0000190023.89759.96
DO - 10.1097/01.inf.0000190023.89759.96
M3 - Article
C2 - 16371871
AN - SCOPUS:29444450740
VL - 24
SP - 1089
EP - 1092
JO - Pediatric Infectious Disease Journal
JF - Pediatric Infectious Disease Journal
SN - 0891-3668
IS - 12
ER -