Characteristics of antibiotic resistance in group A Streptococcus strains isolated from children with scarlet fever

Abstract

Objective To analyze the characteristics of antibiotic resistance in group A Streptococcus (GAS) strains isolated from children with scarlet fever in Tianjin in order to provide reference for clinical drug administration. Methods GAS strains were collected from 2011 to 2016. A total of 276 isolates were analyzed by antibiotic susceptibility test and emm typing. Results All of the isolates were susceptible to penicillin, cefazolin and vancomycin, while 98.2 % were susceptible to both chloramphenicol and levofloxacin. The resistance rates to azithromycin, erythromycin, clarithromycin, clindamycin and tetracycline were 97.8%, 97.1%, 94.2%, 94.2% and 79.3%. The concomitant resistance to erythromycin, azithromycin, clarithromycin, clindamycin and tetracycline was 73.2%. The resistance rates of GAS strains isolated from different years to tetracycline, clindamycin, clarithromycin, erythromycin and azithromycin were significantly different. A statistically significant difference was found between the percentages of emm12 and emm1 strains resistant to tetracycline (84.0% vs 59.5%, χ2=13.820, P=0.000). Conclusions The isolated GAS strains are sensitive to β-lactams and highly resistant to macrolide antibiotics, clindamycin and tetracycline. Penicillin remains the preferred treatment for GAS infection and cephalosporins may be used as a substitute if the patient is allergic to penicillin. Key words: Scarlet fever; Group A Streptococcus; Antibiotic resistance