Stenotrophomonas maltophilia strains from cystic fibrosis patients: Genomic variability and molecular characterization of some virulence determinants

Mauro Nicoletti, Angelo Iacobino, Gianni Prosseda, Ersilia Fiscarelli, Raffaele Zarrilli, Elena De Carolis, Andrea Petrucca, Lucia Nencioni, Bianca Colonna, Mariassunta Casalino

Research output: Contribution to journalArticlepeer-review


The genetic relatedness of 52 Stenotrophomonas maltophilia strains, collected from various environmental and clinical sources, including cystic fibrosis (CF) patients, as well as the presence and the expression of some virulence-associated genes were studied. Pulsed-field gel electrophoresis (PFGE) analysis identified 47 profiles and three clusters of isolates with an identical PFGE pattern considered to be indistinguishable strains. Restriction fragment length polymorphism of the g. yrB gene grouped the 52 strains into nine different profiles. Most CF clinical isolates (29 out of 41) showed profile 1, while the analysis of the hypervariable regions of the 16S rRNA gene revealed five distinct allelic variations, with the majority of CF isolates (23 out of 41) belonging to sequence group 1. Furthermore, the strains were characterized for motility and expression of virulence-associated genes, including genes encoding type-1 fimbriae, proteases (StmPr1 and StmPr2) and esterase. All S. maltophilia strains exhibited a very broad range of swimming and twitching motility, while none showed swarming motility. A complete smf-1 gene was PCR-amplified only from clinically derived S. maltophilia strains. Finally, the virulence of representative S. maltophilia strains impaired in the expression of proteases and esterase activities was evaluated by infecting larvae of the wax moth Galleria mellonella. The results obtained strongly indicate that the major extracellular protease StmPr1 may be a relevant virulence factor of S. maltophilia.

Original languageEnglish
Pages (from-to)34-43
Number of pages10
JournalInternational journal of medical microbiology : IJMM
Issue number1
Publication statusPublished - Jan 2011


  • Animal model
  • Cystic fibrosis
  • Esterase
  • Extracellular proteases
  • Galleria mellonella
  • Molecular typing
  • Stenotrophomonas maltophilia
  • Virulence factors

ASJC Scopus subject areas

  • Microbiology
  • Infectious Diseases
  • Microbiology (medical)


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