14th ICID - Poster Abstracts - International Society for Infectious ...

When citing these abstracts please use the following reference:
Author(s) of abstract. Title of abstract [abstract]. Int J Infect Dis 2010;14S1: Abstract number.
Please note that the official publication of the International Journal of Infectious Diseases 2010, Volume 14, Supplement 1
is available electronically on http://www.sciencedirect.com
Final Abstract Number: 77.014
Session: Gram-positives & Miscellaneous Pathogens
Date: Friday, March 12, 2010
Time: 12:30-13:30
Room: Poster & Exhibition Area/Ground Level
Type: Poster Presentation
Concordance between Vir and protein M gene (emm) types of Streptococcus pyogenes strains
isolated from patients with invasive and non-invasive infections of Mexico
M. Carranza 1 , M. Quiñonez-Alvarado 2 , E. Martìnez-Lopez 3 , L. Perea-Mejia 4 , A. Inzunza-Montiel 4 ,
A. Villaseñor-Sierra 5
1 Centro de Investigación Biomedica de Occidente, IMSS, Guadalajara, Jal, Mexico, 2 3Centro de
investigación Biomédica de Occidente. IMSS,, Guadalajara, Mexico, 3 Hospital Civil de
Guadalajara, Guadalajara, Mexico, 4 Facultad de Medicina, UNAM, Mexico, Mexico, 5 Centro de
investigación Biomédica de Occidente. IMSS, Guadalajara, Mexico
Background: Identification of the emm types of Group A Streptococcus (GAS) strains associated
to invasive infections and acute pharyngitis from Mexico by the protein M gene (emm) typing is
crucial to evaluate the potential usefulness of the 26-valent candidate GAS vaccine developed in
the U.S.A. In the same way, RFLP patterns of other method to type GAS strains such as Vir
typing has been described to have a high concordance with specific emm types, but consistency
has not been proven.
Methods: Cross sectional study. We studied 101 GAS strains isolated of patients with invasive (n
= 32) and non-invasive (n = 69) infections from three cities of Mexico, during the 1999-2008
period. RFLP of the Vir regulon (Vir typing) was performed using HinfI restriction enzyme
according with the technique described by Gardiner et al. The M protein gene (emm) typing of
GAS was performed according with the CDC protocol
(http://www.cdc.gov/ncidod/biotech/strep/protocols.html) described by Beall B.
Results: All the GAS strains were typeable by the M protein gene (emm) typing method. Analysis
of the 101 GAS strains with both techniques resulted in 33 Vir RFLP patterns and 13 M protein
gene (emm) types. Seven emm types (emm12, emm1, emm4, emm6, emm22, emm3, and
emm59) accounted for 79% of the isolates. Other emm types (emm28, emm11, emm49, emm75,
emm77 and emm89) were isolated less frequently. In some cases, a single protein M emm type
resulted in several RFLP patterns by the Vir typing method. All but one (emm4) M protein emm
gene types isolated were included in the 26-valent M protein-based vaccine described by Hu, M
and Dale J et al.
Conclusion: Although the number of GAS strains studied is small, the M protein gene (emm)
typing resulted in the best technique for studying and comparing the genotypes of GAS strains
from this study and elsewhere. The fact that all the GAS strains studied was able to be typed by
the M protein gene (emm) method, and that all but one belonged to the emm types included in
the 26-valent M protein-based vaccine, seems to be promising for the potential of this vaccine in
Mexico.