Bacteriophage genes distribution among GAS belonging to different M serotypes

Abstract number: P1314

Polyakova E., Gao W., Suvorov A., Yang Y., Ferretti J., Totolian A.

Objectives: In spite of the intense use of antibiotics in medical practice, the group A streptococcus (GAS) continues to be one of the most common bacterial pathogens of humans. Recent sequencing information has shown that the GAS possess tremendous genetic variability and one of the reasons for this is the presence of numerous streptococcal bacteriophages, which often carry genes encoding toxins, mitogens, enzymes and antibiotic resistance factors. Little is known about the real impact of specific phage or phage transported virulence genes in GAS pathogenicity. The aim of the present work was to study a possible correlation between the specific M serotype of GAS and bacteriophage content.

Methods: 75 GAS strains belonging to serotypes M1, M12 and M49 (31, 22 and 22) were studied. Streptococcus pyogenes strains type M1 and M12 were obtained from Chinese patients with scarlet fever in Beijing during 2007. M49 strains known to be from patients with invasive disease were obtained from CDC in the USA and collected between 2000–2005. Strains were analysed by PCR with a panel of 27 pairs of primers corresponding to the genes of phage related virulence factors and a set of nine phage related integrases. Results were substantiated by microarray hybridisation.

Results: 75 GAS strains belonging to 3 different M serotypes were analysed by PCR. Among the GAS strains from serotype M49, the highly prevalent genes found were speA, speI, speH, int5 and int7. In M1 strains speA, speH, speC, speC/J, ssa, sdaM, int4 and int7 were determined. In M12 strains the prevalent genes were speH, ssa, speC and int4 (fig1). A distinct correlation was found between the M serotype of GAS under study and phage gene content suggesting that temperate bacteriophages might be an important factors in the development of epidemic strains and may be involved in the triggering of GAS infections.

Phage genes distribution.

Conclusions: PCR analysis of bacteriophage gene content in the epidemic GAS reveals that strains belonging to the same serotype have similar bacteriophage gene patterns. The role of the bacteriophages in GAS pathogenicity is discussed.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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