Insights on evolution of virulence and resistance from the complete genome analysis of an early methicillin-resistant Staphylococcus aureus strain and a biofilm-producing methicillin-resistant Staphylococcus epidermidis strain.
Staphylococcus aureus is an opportunistic pathogen and the major causative agent of numerous hospital- and community-acquired infections. Staphylococcus epidermidis has emerged as a causative agent of infections often associated with implanted medical devices. We have sequenced the approximately 2.8-Mb genome of S. aureus COL, an early methicillin-resistant isolate, and the approximately 2.6-Mb genome of S. epidermidis RP62a, a methicillin-resistant biofilm isolate. Comparative analysis of these and other staphylococcal genomes was used to explore the evolution of virulence and resistance between these two species. The S. aureus and S. epidermidis genomes are syntenic throughout their lengths and share a core set of 1,681 open reading frames. Genome islands in nonsyntenic regions are the primary source of variations in pathogenicity and resistance. Gene transfer between staphylococci and low-GC-content gram-positive bacteria appears to have shaped their virulence and resistance profiles. Integrated plasmids in S. epidermidis carry genes encoding resistance to cadmium and species-specific LPXTG surface proteins. A novel genome island encodes multiple phenol-soluble modulins, a potential S. epidermidis virulence factor. S. epidermidis contains the cap operon, encoding the polyglutamate capsule, a major virulence factor in Bacillus anthracis. Additional phenotypic differences are likely the result of single nucleotide polymorphisms, which are most numerous in cell envelope proteins. Overall differences in pathogenicity can be attributed to genome islands in S. aureus which encode enterotoxins, exotoxins, leukocidins, and leukotoxins not found in S. epidermidis.
Gill
Steven R
SR
Microbial Genomics, The Institute for Genomic Research, 9712 Medical Center Dr., Rockville, MD 20850, USA. srgill@tigr.org
Fouts
Derrick E
DE
Archer
Gordon L
GL
Mongodin
Emmanuel F
EF
Deboy
Robert T
RT
Ravel
Jacques
J
Paulsen
Ian T
IT
Kolonay
James F
JF
Brinkac
Lauren
L
Beanan
Mauren
M
Dodson
Robert J
RJ
Daugherty
Sean C
SC
Madupu
Ramana
R
Angiuoli
Samuel V
SV
Durkin
A Scott
AS
Haft
Daniel H
DH
Vamathevan
Jessica
J
Khouri
Hoda
H
Utterback
Terry
T
Lee
Chris
C
Dimitrov
George
G
Jiang
Lingxia
L
Qin
Haiying
H
Weidman
Jan
J
Tran
Kevin
K
Kang
Kathy
K
Hance
Ioana R
IR
Nelson
Karen E
KE
Fraser
Claire M
CM
D018441:Biofilms; D002874:Chromosome Mapping; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D016680:Genome, Bacterial; D044404:Genomic Islands; D016106:Methicillin Resistance / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D013211:Staphylococcus aureus / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D013212:Staphylococcus epidermidis / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics