The complete genome, comparative and functional analysis of Stenotrophomonas maltophilia reveals an organism heavily shielded by drug resistance determinants.
BACKGROUND
Stenotrophomonas maltophilia is a nosocomial opportunistic pathogen of the Xanthomonadaceae. The organism has been isolated from both clinical and soil environments in addition to the sputum of cystic fibrosis patients and the immunocompromised. Whilst relatively distant phylogenetically, the closest sequenced relatives of S. maltophilia are the plant pathogenic xanthomonads.


RESULTS
The genome of the bacteremia-associated isolate S. maltophilia K279a is 4,851,126 bp and of high G+C content. The sequence reveals an organism with a remarkable capacity for drug and heavy metal resistance. In addition to a number of genes conferring resistance to antimicrobial drugs of different classes via alternative mechanisms, nine resistance-nodulation-division (RND)-type putative antimicrobial efflux systems are present. Functional genomic analysis confirms a role in drug resistance for several of the novel RND efflux pumps. S. maltophilia possesses potentially mobile regions of DNA and encodes a number of pili and fimbriae likely to be involved in adhesion and biofilm formation that may also contribute to increased antimicrobial drug resistance.


CONCLUSIONS
The panoply of antimicrobial drug resistance genes and mobile genetic elements found suggests that the organism can act as a reservoir of antimicrobial drug resistance determinants in a clinical environment, which is an issue of considerable concern.
Crossman
Lisa C
LC
Pathogen Sequencing Unit, The Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK.
Gould
Virginia C
VC
Dow
J Maxwell
JM
Vernikos
Georgios S
GS
Okazaki
Aki
A
Sebaihia
Mohammed
M
Saunders
David
D
Arrowsmith
Claire
C
Carver
Tim
T
Peters
Nicholas
N
Adlem
Ellen
E
Kerhornou
Arnaud
A
Lord
Angela
A
Murphy
Lee
L
Seeger
Katharine
K
Squares
Robert
R
Rutter
Simon
S
Quail
Michael A
MA
Rajandream
Mari-Adele
MA
Harris
David
D
Churcher
Carol
C
Bentley
Stephen D
SD
Parkhill
Julian
J
Thomson
Nicholas R
NR
Avison
Matthew B
MB
D004352:Drug Resistance, Microbial / Q000235:genetics*; D016680:Genome, Bacterial; D019216:Metals, Heavy / Q000633:toxicity; D020615:Stenotrophomonas maltophilia / Q000235:genetics* / Q000502:physiology
D019216:Metals, Heavy