Multilocus sequence typing of Streptococcus pyogenes isolated from children in Shenzhen / 中华实用儿科临床杂志

ABSTRACT

Objective:To explore the epidemiological characteristics of Streptococcus pyogenes, namely β-hemolytic Group A Streptococcus (GAS) in children in Shenzhen. Methods:Multilocus sequence typing (MLST) data on the epidemic clonal population of GAS infection in children in Shenzhen Children′s Hospital from January 2016 to December 2018 were retrospectively analyzed.In the present study, 32 GAS strains belonging to 7 different emm types were from 32 children′s with impetigo, cellulitis, scarlet fever, sepsis, pneumonia, obstructive sleep apnea hypopnea syndrome, bronchitis, allergy with rhinitis, buttock abscess, allergic purpura or pharyngeal tonsillitis, which were isolated from 23 throat swabs, 5 sputum samples, 3 pus and 1 blood.Using polymerase chain reaction technology, 7 pairs of allelic housekeeping genes ( gki, gtr, murI, mutS, recP, xpt and yqiL) of 32 GAS isolates were analyzed, and the target gene products were subjected to sequencing.Then the obtained gene sequences of each allele were submitted to the MLST database to obtain the allele profile.Finally, the allele profiles were introduced in the MLST database again to confirm the sequence typing (ST). Results:The GAS clone groups of emm 1.00 and its subtypes, emm 4.00, emm 12.00 and its subtypes, emm 22.00, emm 28.00, emm 75.00, and emm 89.00 belonged to the sequence typing ST28, ST39, ST36, ST46, ST52, ST49, and ST921, respectively. Conclusions:From 2016 to 2018, the MLST clone populations of GAS isolates causing infections in children in Shenzhen are classified as ST28, ST39, ST36, ST46, ST52, ST49 and ST921.