Identification and genotypic analysis of Streptococcus pyogenes isolated from pharyngitis and tonsillitis infected children in IBB city in Yemen

Streptococcus pyogenes is beta-hemolytic bacterium that belongs to Lancefield serogroup A, also known as group A streptococci (GAS). GAS causes a wide variety of life threatening diseases including pharyngitis and tonsillitis disease. A total of 93 throat swab and 93 blood specimens were collected from pharyngitis and tonsillitis infected children in different schools in Almashana, IBB city in Yemen. All isolates were diagnosis by using two methods: throat swab culture and serological test (ASO test). The result shows difference between throat swab culture method and blood specimens serology method (ASO). 38 isolates (40.8%) for throat swab culture and 60 isolates (64.5%) for blood specimens serology method (ASO) were positive in 93 total isolates. All isolates were characterized by their antimicrobial susceptibility test to different antibiotics including penicillin G, chloramphenicol, erythromycin, clindamycin and streptomycin. All isolates were sensitive to penicillin G and chloramphenicol. Most isolates (61.3%) showed a high degree of resistance to erythromycin. Resistance to clindamycin and streptomycin were observed in 34.4 and 46.2% of isolates, respectively. The 93 isolates were subjected to fingerprinting by random amplified polymorphic DNA (RAPD) analysis. Amplification of genomic DNA of GAS was performed with three primers. The results reveal that approximately 36 different amplified DNA fragments (rapdemes) were observed in all, of which 21 (58.3%) were shared and 15 (41.7%) unshared or unique rapdemes. RAPD analysis provides a practical alternative for genomic typing of GAS. It can be recommended for the typing of GAS, especially if used in parallel with serotyping.   Key words: Group A streptococci (GAS), IBB city, antistreptolysin-O (ASO) test, pharyngitis, random amplified polymorphic DNA (RAPD).