Genome analysis of a highly virulent serotype 1 strain of Streptococcus pneumoniae from West Africa.
Streptococcus pneumoniae is a leading cause of pneumonia, meningitis, and bacteremia, estimated to cause 2 million deaths annually. The majority of pneumococcal mortality occurs in developing countries, with serotype 1 a leading cause in these areas. To begin to better understand the larger impact that serotype 1 strains have in developing countries, we characterized virulence and genetic content of PNI0373, a serotype 1 strain from a diseased patient in The Gambia. PNI0373 and another African serotype 1 strain showed high virulence in a mouse intraperitoneal challenge model, with 20% survival at a dose of 1 cfu. The PNI0373 genome sequence was similar in structure to other pneumococci, with the exception of a 100 kb inversion. PNI0373 showed only 15 lineage specific CDS when compared to the pan-genome of pneumococcus. However analysis of non-core orthologs of pneumococcal genomes, showed serotype 1 strains to be closely related. Three regions were found to be serotype 1 associated and likely products of horizontal gene transfer. A detailed inventory of known virulence factors showed that some functions associated with colonization were absent, consistent with the observation that carriage of this highly virulent serotype is unusual. The African serotype 1 strains thus appear to be closely related to each other and different from other pneumococci despite similar genetic content.
The Genome Institute, Washington University, St. Louis, Missouri, USA.
Tiffany M
TM
Williams
Nicholas J
NJ
Loman
Chinelo
C
Ebruke
Daniel M
DM
Musher
Richard A
RA
Adegbola
Mark J
MJ
Pallen
George M
GM
Weinstock
Martin
M
Antonio
D000354:Africa, Western; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002876:Chromosomes, Bacterial / Q000235:genetics; D017124:Conserved Sequence / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D005798:Genes, Bacterial / Q000235:genetics; D016680:Genome, Bacterial / Q000235:genetics*; D006801:Humans; D051379:Mice; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D039002:Prophages / Q000235:genetics; D012703:Serotyping; D022541:Streptococcal Vaccines / Q000276:immunology; D013296:Streptococcus pneumoniae / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D016019:Survival Analysis; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000378:metabolism
D001426:Bacterial Proteins; D022541:Streptococcal Vaccines; D037521:Virulence Factors