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.
Zhang, X., Hou, F., Li, X., Zhou, L., Liu, Y. and Zhang, T. (2016) Study of Surveillance Data for Class B Notifiable Disease in China from 2005 to 2014. International Journal of Infectious Diseases, 48, 7-13. https://doi.org/10.1016/j.ijid.2016.04.010
You, Y., Davies, M.R., Protani, M., McIntyre, L., Walker, M.J. and Zhang, J. (2018) Scarlet Fever Epidemic in China Caused by Streptococcus pyogenes Serotype M12: Epidemiologic and Molecular Analysis. EBioMedicine, 28, 128-135.
Streptococcus Laboratory of Centers for Disease Control and Prevention (2017) Introduction to emm Typing: M Protein Gene (emm) Typing Streptococcus pyogenes.
Chen, M., Yao, W., Wang, X., Li, Y., Wang, G., Zhang, X., Pan, H., Hu, J. and Zeng, M. (2012) Outbreak of Scarlet Fever Associated with emm 12 Type Group A Streptococcus in 2011 in Shanghai, China. The Pediatric Infectious Disease Journal, 31, e158-162. https://doi.org/10.1097/INF.0b013e31825874f3
Park, D.W., Kim, S.H., Park, J.W., Kim, M.J., Cho, S.J., Park, H.J., Jung, S.H., Seo, M.H., Lee, Y.S., Kim, B.H., Min, H., Lee, S.Y., Ha, D.R., Kim, E.S., Hong, Y. and Chung, J.K. (2017) Incidence and Characteristics of Scarlet Fever, South Korea, 2008-2015. Emerging Infectious Diseases, 23, 658-661.
Turner, C.E., Pyzio, M., Song, B., Lamagni, T., Meltzer, M., Chow, J.Y., Efstratiou, A., Curtis, S. and Sriskandan, S. (2016) Scarlet Fever Upsurge in England and Molecular-Genetic Analysis in North-West London, 2014. Emerging Infectious Diseases, 22, 1075-1078. https://doi.org/10.3201/eid2206.151726
Liu, Z., Fang, M., Hu, B., Bi, Z., Kou, Z., Ren, Y., Chen, B. and Bi, Z. (2014) Molecular Types of Group A Streptococcus Isolated from Scarlet Fever Patients and Asymptomatic Carriers in Shandong Province, 2013. Zhonghua Liu Xing Bing Xue Za Zhi, 35, 1375-1378.