Antimicrobial resistance of Group A streptococcus isolates from patients in Shenzhen, China during COVID-19 pandemic

Background Group a streptococcus (GAS) is one of the few bacterial pathogens that can cause a wide range of infectious diseases and autoimmune diseases. Human beings are the only host of GAS, which is mainly transmitted through airborne droplets and skin mucous membrane contact. The COVID-19 pandemic has changed our way of life. The objective of this study was to investigate the antimicrobial resistance, emm typing and multilocus sequence type (MLST) of GAS isolates from patients in Shenzhen children’s Hospital during COVID-19 pandemic. Methods We collected GAS strains that were isolated, identified and stored in patients (0-18 years old) who visited the outpatient department or ward of Shenzhen Children's Hospital from January 2019 to December 2020. Antimicrobial susceptibility test was performed according to the distribution of conventional antibiotics and Clinical and Laboratory Standards Institute (CLSI) recommendations. The distribution of the macrolide-resistance genes (ermB, ermA, mefA) and tetracycline-resistance gene （tetM， tetO）, emm (M protein-coding gene) typing and multilocus sequence type (MLST) were examined by polymerase chain reaction (PCR). Results All the 124 GAS strains were sensitive to penicillin, and 95.2% were sensitive to levofloxacin. Most strains were resistant to clindamycin, azithromycin, clarithromycin, erythromycin and tetracycline, and the resistance rates were 73.4% (91/124), 78.2% (97/124), 78.2% (97/124), 78.2% (97/124), 75.0% (93/124), respectively. The resistance rate of chloramphenicol was 3.2% (4/124). The rate of macrolide-resistance genes was as follows: 99 strains (79.8%) carried ermB, 55 strains (44.0%) carried ermA, 56 strains (45.1%) carried mefA; Tetracycline-resistance genes carried: 58 strains (46.7%) carried tetO, 100 strains (80.6%) carried tetM; 94 strains carried ermB and tetM together, accounting for 75.8%. A total of 12 emm types were detected in this study. The emm types of 71 GAS isolates were mainly emm1, emm3, emm4, emm6, emm12, emm74, emm75, emm88, emm89 and emm110 in 2019. While emm types of 53 GAS isolates were mainly emm1, emm2, emm3, emm4, emm12 and emm22 in 2020. The clones carrying both Erythromycin-resistance and tetracycline-resistance genes were ST36/emm12, ST28/emm1, ST15/emm3 and ST39/ emm4. Conclusions Under COVID-19 pandemic, our collections of GAS strains decreased dramatically. The resistance rate of GAS strains in 2020 increased slightly compared with 2019. The main emm types analysis of GAS infections among children during COVID-19 pandemic was not significantly different from our previous study. On the whole, Continuous surveillance of antibiotics resistance pattern of GAS must be strengthen to improve the reasonable use of antibiotics in hospitals.