PMID:1713075

Citation	Fessia, SL and Griffin, MJ (1991) A method for assaying biofilm capacity on polyurethane-coated slides.Perit Dial Int 11:144-6
Abstract	Isolates of coagulase-negative Staphylococci (CNS) were examined for their ability to form biofilms on polyurethane-coated slides. These slides provided a smooth plastic coating simulating polymeric plastic surfaces of medical grade catheter tubing. Slides were placed into plastic conical tubes containing tryptic soy broth inoculated with 10(6) bacteria per mL. The tubes were then incubated at 37 degrees for 48 hours. After incubation, 1 of the slides was stained with a fluorescent acridine orange stain and the other with a safranin stain. The incubation tubes were also stained with safranin. Forty-eight percent of the 65 CNS isolates were found to form a biofilm using acridine orange staining. Forty percent of the 65 CNS isolates were found to form a biofilm using the safranin stain on slides, whereas only 34% were found to adhere on sides of plastic tubes. Increased sensitivity of the fluorescent stain was probably due to enhanced visualization of smaller numbers of bacteria on the plastic. This method using fluorescent stained plastic-coated slides was easier to visualize and interpret than the tube method.
Links	PubMed
Keywords	Acridine Orange; Bacterial Adhesion; Catheters, Indwelling; Humans; Peritonitis; Phenazines; Polyurethanes; Staining and Labeling; Staphylococcal Infections; Staphylococcus; Staphylococcus epidermidis; Biofilm; Coagulase-negative; Glycoca
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Main Points of the Paper

Please summarize the main points of the paper.

• Slides were used to test a strain's ability to form biofilms
  • 48% of the 65 isolates tested formed biofilm
• Slide method was compared to the tube method for assessing biofilm formation
  • slides were easier to visualize and interpret than the tube method

Materials and Methods Used

Please list the materials and methods used in this paper (strains, plasmids, antibodies, etc).

• Strain identification
  • 65 clinical isolates of Coagulase-negative Staphylococci(CNS) from peritoneal fluid, blood, wounds, and skin
  • blood agar
  • coagulase test
  • STAPH-TracTM

• To grow biofilms
  • Microscope slides sprayed with Zip guard spray containing 9.9% polyurethane resin Type I with 1.1% silicates
  • 50ml conical tubes
  • 40ml tryptic soy

• • To test for biofilm
  • Vacutainer acridine orange stain
  • Accra Lab safranin stain

• To visualize/compare staining results
  • Zeiss epifluorescent microscope (acridine orange)
  • Light microscopy (safrinin)
  • observation of slime in broth culture (as confirmation of the capacity of CNS-isolates to form biofilms)

Phenotype Annotations

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Species	Taxon ID	Strain	Gene (if known)	OMP	Phenotype	Details	Evidence	Notes
Staphylococcus epidermidis	NCBI:1282				Morphology	Positive for biofilm formation- adherence to slides after incubation	Staining	Acridine orange/ safranin staining
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Notes

• Absolute positives were determined by the production of visible slime in the bottom of the culture tube
• Authors note that difficulties in interpretation arise when the stains tint the plastic
• Authors also note that acridine orange was determined to be more sensitive, due to the ability to visualize small numbers of cells