title: The impact of spgM, rpfF, rmlA gene distribution on biofilm formation in Stenotrophomonas maltophilia.
abstract: BACKGROUND
  Stenotrophomonas maltophilia is emerging as one of the most frequently found bacteria in chronic pulmonary infection. Biofilm is increasingly recognized as a contributing factor to disease pathogenesis. In the present study, a total of 37 isolates of S. maltophilia obtained from chronic pulmonary infection patients were evaluated to the relationship between biofilm production and the relative genes expression.
  
  
  METHODS
  The clonal relatedness of isolates was determined by pulse-field gel electrophoresis. Biofilm formation assays were performed by crystal violet assay, and confirmed by Electron microscopy analysis and CLSM analysis. PCR was employed to learn gene distribution and expression.
  
  
  RESULTS
  Twenty-four pulsotypes were designated for 37 S. maltophilia isolates, and these 24 pulsotypes exhibited various levels of biofilm production, 8 strong biofilm-producing S. maltophilia strains with OD492 value above 0.6, 14 middle biofilm-producing strains with OD492 average value of 0.4 and 2 weak biofilm-producing strains with OD492 average value of 0.19. CLSM analysis showed that the isolates from the early stage of chronic infection enable to form more highly structured and multilayered biofim than those in the late stage. The prevalence of spgM, rmlA, and rpfF genes was 83.3%, 87.5%, and 50.0% in 24 S. maltophilia strains, respectively, and the presence of rmlA, spgM or rpfF had a close relationship with biofilm formation but did not significantly affect the mean amount of biofilm. Significant mutations of spgM and rmlA were found in both strong and weak biofilm-producing strains.
  
  
  CONCLUSIONS
  Mutations in spgM and rmlA may be relevant to biofilm formation in the clinical isolates of S. maltophilia.
authors.affiliation: State Key Laboratory of Respiratory Diseases, the first affiliated hospital of Guangzhou Medical College, Guangzhou, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhuo
authors.affiliation: State Key Laboratory of Respiratory Diseases, the first affiliated hospital of Guangzhou Medical College, Guangzhou, China.
authors.forename: Qian-yu
authors.initials: QY
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Respiratory Diseases, the first affiliated hospital of Guangzhou Medical College, Guangzhou, China.
authors.forename: Shu-nian
authors.initials: SN
authors.lastname: Xiao
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D018441:Biofilms; D016521:Electrophoresis, Gel, Pulsed-Field; D005798:Genes, Bacterial; D005838:Genotype; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D020615:Stenotrophomonas maltophilia / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D001426:Bacterial Proteins