title: Virulence of Bacteria Colonizing Vascular Bundles in Ischemic Lower Limbs.
abstract: BACKGROUND
  We documented previously the presence of bacterial flora in vascular bundles, lymphatics, and lymph nodes of ischemic lower limbs amputated because of multifocal atheromatic changes that made them unsuitable for reconstructive surgery and discussed their potential role in tissue destruction. The question arose why bacterial strains inhabiting lower limb skin and considered to be saprophytes become pathogenic once they colonize deep tissues. Bacterial pathogenicity is evoked by activation of multiple virulence factors encoded by groups of genes.
  
  
  METHODS
  We identified virulence genes in bacteria cultured from deep tissue of ischemic legs of 50 patients using a polymerase chain reaction technique.
  
  
  RESULTS
  The staphylococcal virulence genes fnbA (fibronectin-binding protein A), cna (collagen adhesin precursor), and ica (intercellular adhesion) were present in bacteria isolated from both arteries and, to a lesser extent, skin. The IS256 gene, whose product is responsible for biofilm formation, was more frequent in bacteria retrieved from the arteries than skin bacteria. Among the virulence genes of Staphylococcus epidermidis encoding autolysin atlE, icaAB (intercellular adhesion), and biofilm insert IS256, only the latter was detected in arterial specimens. Bacteria cultured from the lymphatics did not reveal expression of eta and IS256 in arteries. The Enterococcus faecalis asa 373 (aggregation substance) and cylA (cytolysin activator) frequency was greater in arteries than in skin bacteria, as were the E. faecium cyl A genes. All Pseudomonas aeruginosa virulence genes were present in bacteria cultured from both the skin and arteries. Staphylococci colonizing arterial bundles and transported to tissues via ischemic limb lymphatics expressed virulence genes at greater frequency than did those dwelling on the skin surface. Moreover, enterococci and Pseudomonas isolated from arterial bundles expressed many virulence genes.
  
  
  CONCLUSIONS
  These findings may add to the understanding of the mechanism of development of destructive changes in lower limb ischemic tissues by the patient's, but not hospital-acquired, bacteria, as well as the generally unsatisfactory results of antibiotic administration in these cases. More aggressive antibiotic therapy targeted at the virulent species should be applied.
authors.affiliation: 1 Department of Surgical Research Transplantation, Mossakowski Medical Research Centre , Polish Academy of Sciences, Warsaw, Poland.|2 Central Clinical Hospital , Ministry of Internal Affairs, Warsaw, Poland .
authors.forename: Waldemar L
authors.initials: WL
authors.lastname: Olszewski
authors.affiliation: 1 Department of Surgical Research Transplantation, Mossakowski Medical Research Centre , Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Adrianna
authors.initials: A
authors.lastname: Podbielska
authors.affiliation: 1 Department of Surgical Research Transplantation, Mossakowski Medical Research Centre , Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Galkowska
authors.affiliation: 3 Department of Clinical Bacteriology, Warsaw Medical University , Warsaw, Poland .
authors.forename: Marlena
authors.initials: M
authors.lastname: Golas
authors.affiliation: 3 Department of Clinical Bacteriology, Warsaw Medical University , Warsaw, Poland .
authors.forename: Katarzyn
authors.initials: K
authors.lastname: Piskorska
authors.affiliation: 4 Department of Human Epigenetics, Mossakowski Medical Research Centre , Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Stelmach
authors.affiliation: 3 Department of Clinical Bacteriology, Warsaw Medical University , Warsaw, Poland .
authors.forename: Ewa
authors.initials: E
authors.lastname: Swoboda
authors.affiliation: 2 Central Clinical Hospital , Ministry of Internal Affairs, Warsaw, Poland .|4 Department of Human Epigenetics, Mossakowski Medical Research Centre , Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Marzamma
authors.initials: M
authors.lastname: Zaleska
authors.affiliation: 1 Department of Surgical Research Transplantation, Mossakowski Medical Research Centre , Polish Academy of Sciences, Warsaw, Poland.|2 Central Clinical Hospital , Ministry of Internal Affairs, Warsaw, Poland .
authors.forename: Marek
authors.initials: M
authors.lastname: Durlik
mesh_terms: D000368:Aged; D001419:Bacteria / Q000302:isolation & purification / Q000472:pathogenicity*; D001424:Bacterial Infections / Q000382:microbiology*; D005260:Female; D006801:Humans; D007511:Ischemia / Q000150:complications*; D035002:Lower Extremity / Q000473:pathology*; D008199:Lymphadenitis / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D014657:Vasculitis / Q000382:microbiology*; D037521:Virulence Factors / Q000032:analysis*
chemical_list: D037521:Virulence Factors