Analysis of genomic characteristics and drug sensitivities of group A Streptococcus emm12 in Hainan Province in 2022
Objective To understand the genomic characteristics and sensitivity to currently commonly used antibacterial drugs of group A Streptococcus(GAS)emm12 in Hainan,and to provide etiological data for GAS-related diseases such as scarlet fever.Methods Based on the throat swab isolates of GAS obtained from respiratory syndrome surveillance in Hainan Province in 2022,next-generation sequencing(NGS)was used to conduct genome sequencing,emm genotyping,gene multi-locus sequence typing(MLST),mobile genetic element annotation,drug resistance gene and virulence gene prediction.The phylogenetic tree was constructed using the maximum likelihood(ML)method of MEGA 10.1.8.Minimum inhibitory concentration(MIC)values were determined using the microbroth dilution method for antimicrobial susceptibility testing.Results The four GAS isolates from the 2022 Hainan respiratory syndrome surveillance were all emm12/ST36 types.In addition to the emm gene,a total of 7 superantigen genes were detected:speB(100%),speI(75%),speH(75%),speC(100%),ssa(100%),smeZ(100%),and speG(100%).All strains carried the macrolide resistance genes ermB and ermTM,and tetracycline resistance gene tet(M),none of them carried the resistance gene mefA.The resistance rates to erythromycin,clindamycin,and tetracycline were 100%,while high sensitivity to penicillin was maintained.The phylogenetic tree showed that the Hainan isolates clustered on the same evolutionary branch.Conclusions In 2022,the dominant genotype of GAS in Hainan is emm12 type,with consistency between MLST and emm typing.The carried resistance genes are consistent with the drug susceptibility test results.β-lactam drugs such as penicillin can continue to be the first choice for clinical treatment of GAS in Hainan,and further monitoring with an expanded number of strains is needed.
Scalet fevergroup A Streptococcusemm12superantigensdrug sensitivities
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