Molecular epidemiological characteristics of scarlet fever among children in Minhang District, Shanghai, 2023-2024
- Author:
ZHANG Chi
;
CHEN Xi
;
TONG Rui
;
LIU Xiaohua
- Publication Type:Journal Article
- Keywords:
Scarlet fever;
group A streptococcus;
antibiotic resistance;
emm genes;
superantigen
- From:
China Tropical Medicine
2024;24(12):1458-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To explore and analyze the epidemiological characteristics of scarlet fever caused by group A Streptococcus (GAS) in Minhang District, Shanghai from 2023 to 2024, providing relevant information for clinical treatment and infection control. Methods Throat swab specimens were collected from children clinically diagnosed with scarlet fever at a sentinel hospital in Shanghai from May 2023 to June 2024. GAS strains were isolated and cultured using blood agar plates, and mass spectrometry performed species identification. The polymerase chain reaction (PCR) method was used to assess emm gene typing and 11 superantigens, while the broth microdilution method was used to determine the resistance of the strains to 14 antibiotics. Whole genome sequencing was performed on 68 GAS strains. The chi-square test and Fisher's exact probability method were conducted for intergroup comparisons. Results A total of 178 GAS strains were isolated from 305 throat swab specimens of scarlet fever cases in children. All GAS strains were sensitive to penicillin, cefotaxime, linezolid, vancomycin, meropenem, chloramphenicol, levofloxacin, teicoplanin, and cefepime, while the resistance rates to erythromycin, clarithromycin, and tetracycline were 99.44%, 99.44%, and 94.94%, respectively. There are two types of emm genes, with emm12 being the main type (89.33%, 159/178), followed by emm1 10.7% (19/178). There were 26 types of superantigen gene spectrums. The speA gene carrying rate of emm1 type GAS (94.74%, 18/19) was significantly higher than emm12(12.00%,32/159) (χ2=46.77, P<0.001). The simultaneous carrying rate of speH and speI genes in emm12 type GAS (59.75%, 95/159) was higher than in emm1 type (0) (χ2=24.35, P<0.001). Whole-genome sequencing revealed that all 68 GAS strains carried the drug resistance gene ermB, with 98.52% (67/68) carrying tetM. Conclusions In Minhang District of Shanghai, non-invasive scarlet fever in children is predominantly caused by emm12 GAS, which shows high resistance to erythromycin, clindamycin, and tetracycline, with higher carriage rates of speH and speI in emm12 types compared to other strains.
- Full text:20251113151008013665.Molecular epidemiological characteristics of scarlet fever among children in Minhang District, Shanghai, 2023-2024.pdf
