High diversity of group A streptococcal emm types among healthy schoolchildren in Ethiopia.
BACKGROUND
Although the prevalence of rheumatic heart disease in Ethiopia is one of the highest in the world, the epidemiology of group A streptococci (GAS) in this country is little known. GAS typing is a hallmark of both the epidemiology and understanding of diseases caused by these organisms. We have therefore conducted this study to investigate the emm (M-protein gene) type distribution of GAS carriers among Ethiopian schoolchildren.


METHODS
In the present study, we performed emm typing of 82 GAS isolates collected from the throats of healthy schoolchildren (6-14 years of age) residing in 3 different urban sites in Ethiopia: Addis Ababa, Gondar, and Dire Dawa.


RESULTS
We report high diversity of GAS isolates recovered from healthy schoolchildren. Eighty-two isolates represented 43 different sequence types. Thirteen newly described subtypes were detected in this study. Of the emm types prevalent in the study communities, 46% were not included in the 26-valent GAS vaccine.


CONCLUSIONS
The high diversity of emm types encountered within 3 months of collection suggest that production of a vaccine candidate based on the M-protein amino termini appears to be impractical for this population. We suggest that investigations of other vaccine candidates, including the C5a peptidase, GAS carbohydrate, and fibronectin-binding proteins, as well as conserved M-protein region vaccines, should be intensified to address the needs of this population.
Abdissa
Alemseged
A
Armauer Hansen Research Institute, Addis Ababa University, Addis Ababa, Ethiopia. alemable@yahoo.com
Asrat
Daniel
D
Kronvall
Göran
G
Shittu
Belay
B
Achiko
Dilachew
D
Zeidan
Mohammed
M
Yamuah
Lawrence K
LK
Aseffa
Abraham
A
D000293:Adolescent; D000942:Antigens, Bacterial / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D002648:Child; D017931:DNA Primers; D004269:DNA, Bacterial / Q000235:genetics; D005002:Ethiopia; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D012016:Reference Values; D013297:Streptococcus pyogenes / Q000235:genetics / Q000302:isolation & purification*
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; C014689:streptococcal M protein