TITLE:
Investigation of Streptococcus pyogenes Carriage in Population Vulnerable to Scarlet Fever during 2015-2017 in Shanghai, China
AUTHORS:
Mingliang Chen, Chi Zhang, Dechuan Kong, Hao Pan, Xi Zhang, Min Chen
KEYWORDS:
Scarlet Fever, Carriage Rate, Child, Emm type, Superantigen
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.6 No.11,
November
19,
2018
ABSTRACT: This study aimed to investigate the carriage of Streptococcus pyogenes in population vulnerable to scarlet fever and to compare their genotypic characterization between different age groups. Pharyngeal swabs were collected from 120 - 150 students in each of the three districts in Shanghai in May and December during 2015 to 2017, while emm typing and detection of 12 superantigen genes were performed to characterize the isolates. During 2015-2017, the average carriage rate in students was 5.7% (135/2,371), without significant difference between different years or districts. The carriage rate was significantly different between children from the three age groups, with 2.4% in 3 - 4 years, 5.4% in 5 - 9 years, and 9.1% in 10 - 14 years. Eight emm types were found, including emm 1, emm 4, emm 12, emm 22, emm 75, emm 89, emm 70 and emm 241, among which emm 12 accounted for 60%, and emm 1 27.5%. The predominance of emm 12 was found in each year, but the proportion of emm 12 was lower in 10 - 14 years (43.3%) than in 3 - 4 years (86.7%) and in 5 - 9 years (73.3%) (P = 0.002 and 0.003). Superantigen genes of speB, speC, speG, ssa and smeZ were found in almost all the isolates. The average carriage of S. pyogenes in population vulnerable to scarlet fever was 5.7% in Shanghai, highest in 10 - 14 years (9.1%), while emm 12 was the predominant type.