Differences in genotype and virulence among four multidrug-resistant Streptococcus pneumoniae isolates belonging to the PMEN1 clone.
We report on the comparative genomics and characterization of the virulence phenotypes of four S. pneumoniae strains that belong to the multidrug resistant clone PMEN1 (Spain(23F) ST81). Strains SV35-T23 and SV36-T3 were recovered in 1996 from the nasopharynx of patients at an AIDS hospice in New York. Strain SV36-T3 expressed capsule type 3 which is unusual for this clone and represents the product of an in vivo capsular switch event. A third PMEN1 isolate - PN4595-T23 - was recovered in 1996 from the nasopharynx of a child attending day care in Portugal, and a fourth strain - ATCC700669 - was originally isolated from a patient with pneumococcal disease in Spain in 1984. We compared the genomes among four PMEN1 strains and 47 previously sequenced pneumococcal isolates for gene possession differences and allelic variations within core genes. In contrast to the 47 strains - representing a variety of clonal types - the four PMEN1 strains grouped closely together, demonstrating high genomic conservation within this lineage relative to the rest of the species. In the four PMEN1 strains allelic and gene possession differences were clustered into 18 genomic regions including the capsule, the blp bacteriocins, erythromycin resistance, the MM1-2008 prophage and multiple cell wall anchored proteins. In spite of their genomic similarity, the high resolution chinchilla model was able to detect variations in virulence properties of the PMEN1 strains highlighting how small genic or allelic variation can lead to significant changes in pathogenicity and making this set of strains ideal for the identification of novel virulence determinants.
Allegheny General Hospital, Allegheny-Singer Research Institute, Center for Genomic Sciences, Pittsburgh, Pennsylvania, United States of America.
N Luisa
NL
Hiller
Rory A
RA
Eutsey
Evan
E
Powell
Joshua P
JP
Earl
Benjamin
B
Janto
Darren P
DP
Martin
Suzanne
S
Dawid
Azad
A
Ahmed
Mark J
MJ
Longwell
Margaret E
ME
Dahlgren
Suzanne
S
Ezzo
Herve
H
Tettelin
Sean C
SC
Daugherty
Timothy J
TJ
Mitchell
Todd A
TA
Hillman
Farrel J
FJ
Buchinsky
Alexander
A
Tomasz
Herminia
H
de Lencastre
Raquel
R
Sá-Leão
J Christopher
JC
Post
Fen Z
FZ
Hu
Garth D
GD
Ehrlich
D016667:Bacterial Capsules / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001430:Bacteriocins / Q000235:genetics; D002473:Cell Wall / Q000378:metabolism; D018432:Drug Resistance, Multiple / Q000235:genetics*; D004917:Erythromycin / Q000494:pharmacology; D016680:Genome, Bacterial / Q000235:genetics; D005838:Genotype; D009305:Nasopharynx / Q000382:microbiology; D010033:Otitis Media / Q000382:microbiology; D010770:Phosphotransferases / Q000235:genetics; D010802:Phylogeny; D039002:Prophages / Q000235:genetics; D017421:Sequence Analysis; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity* / Q000821:virology
D001426:Bacterial Proteins; D001430:Bacteriocins; D004917:Erythromycin; D010770:Phosphotransferases