title: Correlation between staphylococcal biofilm formation in vitro and potential for catheter-related infections.
abstract: BACKGROUND
  The present study evaluated biofilm-forming capacity and the presence of both icaA and icaD genes among staphylococcal strains isolated from catheter-related infections and blood culture.
  
  
  METHODS
  Ninety staphylococcal isolates, which included 45 strains of catheter infection origin and 45 strains of blood culture origin, were tested for their ability to produce biofilm using microtiter test plates and a catheter test. The presence of icaA and icaD genes was determined by polymerase chain reaction (PCR).
  
  
  RESULTS
  Of the 45 strains of catheter infection origin, 22 (48.88%) formed biofilm. In comparison, only 10 (22.22%) of the 45 strains of blood culture origin formed biofilms. Similar results were obtained from both the microplate test and catheter test. In the 32 strains that were able to form biofilm, 30 were positive for icaA and icaD genes, and the remaining 2 strains were negative for both genes. Fifteen staphylococcal strains of all origins presented only the icaA locus and did not form biofilm. In 88 of 90 tested strains (97.77%), there was a positive correlation between biofilm production and presence of icaA and icaD genes, and between no biofilm production and absence of both or only one of the tested genes.
  
  
  CONCLUSIONS
  The ability of staphylococcal isolates to form biofilm in vitro appears to be an indication of a virulence trait that enhances the ability of isolates to cause catheter-related infections. In addition, our results indicate an important role of ica genes and phenotypic variability of biofilm production as virulence factors in staphylococcal infections.
authors.affiliation: Faculty of Medecine and Pharmacy, Hassan II University, Casablanca, Morocco. salwa.oufrid@gmail.com.
authors.forename: Salwa
authors.initials: S
authors.lastname: Oufrid
authors.forename: Zineb
authors.initials: Z
authors.lastname: Ghazlane
authors.forename: Loubna
authors.initials: L
authors.lastname: Jamali
authors.forename: Fatima
authors.initials: F
authors.lastname: El Otmani
authors.forename: Mustapha
authors.initials: M
authors.lastname: Talmi
authors.forename: Naima
authors.initials: N
authors.lastname: Elmdaghri
authors.forename: Khalid
authors.initials: K
authors.lastname: Zerouali
authors.forename: Mohammed
authors.initials: M
authors.lastname: Timinouni
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms / Q000254:growth & development*; D055499:Catheter-Related Infections / Q000382:microbiology*; D006801:Humans; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000382:microbiology*; D013210:Staphylococcus / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors