TY - JOUR
T1 - Capsule-negative EMM types are an increasing cause of pediatric group a streptococcal infections at a large pediatric hospital in Texas
AU - Flores, Anthony R.
AU - Chase McNeil, J.
AU - Shah, Brittany
AU - Van Beneden, Chris
AU - Shelburne, Samuel A.
N1 - Funding Information:
Financial support. This work was supported by the National Institutes of Allergy and Infectious Diseases at the National Institutes of Health (grants R01AI125292 to S. A. S. and R01AI125216 to A. R. F.).
Publisher Copyright:
© The Author(s) 2018.
PY - 2019/7/1
Y1 - 2019/7/1
N2 - Background. Bacterial infections caused by group A Streptococcus (GAS) are common in childhood. Few study reports have provided data on pediatric-specific trends in the epidemiology and bacterial strain characteristics of GAS infections. Methods. We prospectively collected GAS isolates from the clinical microbiology laboratory at Texas Children's Hospital between July 1, 2013, and June 30, 2017. Patient characteristics and GAS disease categories were determined through chart review. GAS isolates were obtained from patients in either the inpatient or outpatient setting, and cases were defined as pharyngeal disease, skin and soft-tissue infection (SSTI), or invasive disease on the basis of predefined criteria. All isolates were emm typed to determine trends over time. Results. We identified 930 cases over the 4-year period, including 432 (46.4%) pharyngeal, 235 (25.3%) SSTI, and 263 (28.3%) invasive disease types. The most frequently encountered emm types were emm1 (21.4%), emm12 (15.7%), emm89 (14.6%), emm4 (9.2%), and emm3 (8.2%). We observed significant changes over the 4-year period in the relative frequency of infections caused by emm1 (−17.7%; P = .046), emm4 (8.7%; P = .023), or emm6 (−7.9%; P = .024). Using bioinformatic analyses and targeted gene sequencing, we also discovered that all GAS emm28 and emm87 types harbored mutations that rendered them incapable of producing capsule. The relative frequency of GAS disease cases caused by capsule-negative GAS emm types (emm4, emm22, emm28, emm87, and emm89) increased over the 4-year period (32.2%-44.4%), although the difference was statistically significant for only nonpharyngeal disease types (27.1%-43.9%; P = .038). Conclusions. Our data suggest an evolving epidemiology of GAS in the Houston pediatric population characterized by an increase in the frequency of capsule-negative emm types.
AB - Background. Bacterial infections caused by group A Streptococcus (GAS) are common in childhood. Few study reports have provided data on pediatric-specific trends in the epidemiology and bacterial strain characteristics of GAS infections. Methods. We prospectively collected GAS isolates from the clinical microbiology laboratory at Texas Children's Hospital between July 1, 2013, and June 30, 2017. Patient characteristics and GAS disease categories were determined through chart review. GAS isolates were obtained from patients in either the inpatient or outpatient setting, and cases were defined as pharyngeal disease, skin and soft-tissue infection (SSTI), or invasive disease on the basis of predefined criteria. All isolates were emm typed to determine trends over time. Results. We identified 930 cases over the 4-year period, including 432 (46.4%) pharyngeal, 235 (25.3%) SSTI, and 263 (28.3%) invasive disease types. The most frequently encountered emm types were emm1 (21.4%), emm12 (15.7%), emm89 (14.6%), emm4 (9.2%), and emm3 (8.2%). We observed significant changes over the 4-year period in the relative frequency of infections caused by emm1 (−17.7%; P = .046), emm4 (8.7%; P = .023), or emm6 (−7.9%; P = .024). Using bioinformatic analyses and targeted gene sequencing, we also discovered that all GAS emm28 and emm87 types harbored mutations that rendered them incapable of producing capsule. The relative frequency of GAS disease cases caused by capsule-negative GAS emm types (emm4, emm22, emm28, emm87, and emm89) increased over the 4-year period (32.2%-44.4%), although the difference was statistically significant for only nonpharyngeal disease types (27.1%-43.9%; P = .038). Conclusions. Our data suggest an evolving epidemiology of GAS in the Houston pediatric population characterized by an increase in the frequency of capsule-negative emm types.
KW - Capsule
KW - Emm type
KW - Epidemiology
KW - Group A Streptococcus
KW - Invasive
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U2 - 10.1093/jpids/piy053
DO - 10.1093/jpids/piy053
M3 - Article
C2 - 30085121
AN - SCOPUS:85057973845
SN - 2048-7193
VL - 8
SP - 244
EP - 250
JO - Journal of the Pediatric Infectious Diseases Society
JF - Journal of the Pediatric Infectious Diseases Society
IS - 3
ER -