Yvonne Fouhy,¹ Karl Scanlon,¹† Katherine Schouest,² Charles Spillane,² Lisa Crossman,³ Matthew B. Avison,⁴ Robert P. Ryan,¹ and J. Maxwell Dow¹*

BIOMERIT Research Centre, Department of Microbiology, BioSciences Institute, National University of Ireland, Cork, Ireland.

Abstract

The genome of Stenotrophomonas maltophilia encodes a cell-cell signaling system that is highly related to the diffusible signal factor (DSF)-dependent system of the phytopathogen Xanthomonas campestris. Here we show that in S. maltophilia, DSF signaling controls factors contributing to the virulence and antibiotic resistance of this important nosocomial pathogen.Stenotrophomonas maltophilia is a gram-negative bacterium that is widespread in the environment and that has become important in the last 15 years as an emerging opportunistic pathogen associated with nosocomial colonization and infection (9, 23, 36). S. maltophilia is frequently isolated from clinical specimens and is implicated in catheter-related bacteremia and septicemia, urinary and respiratory tract infections, and endocarditis (9, 23, 36). Infections occur in cystic fibrosis and burn patients and are common in individuals with impaired defenses who are susceptible to opportunistic infections. The treatment of S. maltophilia infections is problematic, as isolates are resistant to many clinically useful antibiotics. A number of laboratories have begun to address the molecular bases for the broad antibiotic resistance and for virulence in S. maltophilia (14, 25, 29, 31, 34, 48). Cell-cell signaling is known to regulate diverse functions that contribute to the virulence and persistence of bacterial pathogens of both animals and plants (43, 45). However cell-cell signaling systems in S. maltophilia have not yet been described, and their role (if any) in regulation of these properties has therefore not been tested.

Keywords:Stenotrophomonas maltophilia,Nosocomial Pathogen,Cell Signaling,Xanthomonas campestris, pathogens.