Streptococcus pyogenes (group A streptococcus, GAS) is causative agent of numerous diseases in human. Recently, the novel 64,9 kb integrative and conjugative element with tetracycline and macrolide resistance genes designated ICE-emm12, was discovered in some of Hong Kong isolates associated with scarlet fever outbreaks in South-East Asia in 2011-2012.
Goal of this study was to analyze an occurrence of ICE-emm12 element among Vietnamese and Russian GAS strains.
A total of 49 Vietnamese strains and 33 Russian strains were studied. Strains were cultured in THY broth. DNA was isolated by phenol/chloroform extraction. Presence of ICE-emm12 was tested by PCR. Sequence of ICE-emm12 element of Vietnamese strain was determined by Next Generation Sequencing. Pulsed field gel electrophoresis (PFGE) was done as previously described. emm-typing was done as recommended by the Centers for Disease Control and Prevention. All strains were tested for susceptibility to erythromycin and tetracycline.
Complete sequence of ICE-emm12 element of Vietnamese GAS strain was identical to that of Hong Kong isolate. ICE-emm12 element was discovered in 11 out of 49 (22,4%) Vietnamese strains, and 1 out of 33 (3,0%) Russian strains. These 11 Vietnamese strains were isolated in different regions of Vietnam in 2013-2014 and belonged to emm12 genotype. They were resistant to erythromycin and tetracycline and characterized by similar PFGE patterns. In contrast, Russian ICE-emm12 positive strain belonged to emm88.2 genotype. Interestingly, this ICE-emm12 positive strain was isolated in Moscow in 2008 that can give new insight at evolution of ICE-emm12 and arise of epidemiologically actual emm12 GAS clones.