Characterization of streptococcus pyogenes isolates from Lebanon. (c2012)

Abstract

Streptococcus pyogenes (Group A Streptococcus [GAS]) is one of the clinically most important human pathogens responsible for numerous diseases with diverse clinical manifestations. GAS infections range from mild superficial skin infections to life-threatening systemic diseases associated with high morbidity and mortality rates. As the epidemiology of GAS infections changes, a rapid and trustworthy characterization of the isolates is required for epidemiological analysis and infection control. This study aimed at the molecular characterization of GAS isolated from Lebanon. Isolates were characterized by emm typing, superantigen and antibiotic profiles. Fourty-one distinct emm types were detected among the 150 isolates, the most prevalent of which were emm types: 89 (16%), 12 (10%), 2 (9%) and 1 (8%), previously associated with invasive infections. Five isolates were non-typeable. Antibiotic susceptibility testing against seven different classes revealed that all were susceptible to vancomycin, penicillin G and ampicillin, 9% were resistant to clindamycin, 23% were resistant to erythromycin and only 4% were resistant to erythromycin and clindamycin, showing the macrolide–lincosamide–streptogramin B phenotype. An unexpected high emergence of tetracycline resistant strains (37%) was noted and hence our results confirm that resistance of S. pyogenes is a significant problem in Lebanon. Testing for superantigen showed that SpeB (87%) followed by ssa (36%) and SpeG (30%) were the predominant superantigens recovered, but no clear conclusion was excluded from this study concerning the role of superantigens in disease manifestation. This study provides a database of emm sequences, resistance patterns and superantigen profiles of S. pyogenes, which will assist in long-term epidemiological and evolutionary studies of this significant pathogen in Lebanon. Further surveillance studies are required to understand the local epidemiology of GAS in Lebanon.