TABLE 2

Effectiveness of tetrasodium EDTA at killing clinically relevant microorganisms grown as single cells or as biofilms

Organism typeaResult (%) by:Biofilm
killingb
MICMBCMBEC
Gram-positive bacteria
    Staphylococcus epidermidis
        ON0.0630.51.04.2
        SK0.0630.52.03.7
    Staphylococcus aureus
        ON0.0631.0c4.06.0
        Methicillin resistant
            ON0.0631.00.54.6
            SK0.0632.0c4.04.4
    Enterococcus faecalis
        ON0.0632.04.03.7
        Vancomycin resistant (SK)0.0312.00.251.8
Gram-negative bacteria
    Escherichia coli
        ON0.51.01.05.6
        SK0.1250.252.04.4
    Stenotrophomonas maltophilia (ON)0.0631.04.06.5
    Pseudomonas aeruginosa (SK)0.251.04.05.3
    Enterobacter agglomerans (ON)0.1250.254.05.1
    Serratia marcescens (SK)1.01.04.05.0
    Proteus mirabilis (ON)0.0632.04.05.7
    Klebsiella pneumoniae (SK)1.01.02.04.6
Fungi
    Candida albicans
        ON1.02.01.02.7
        SK1.01.01.01.7
    Candida glabrata
        ON0.252.01.01.9
        SK0.1252.01.02.0
Control bacteria
    Salmonella enterica serovar Typhimurium0.250.51.04.7
  • a Microorganisms were obtained from Southlake Regional Health Centre in Ontario (ON) and Royal University Hospital in Saskatchewan (SK).

  • b These numbers refer to the log10 reductions of differences between the mean starting number of cells in the biofilm and the mean number of remaining cells after treatment with tetrasodium EDTA for 24 h at the concentrations listed in the MBEC column.

  • c MBC was determined by confirming the lack of surviving cells through inoculation of the treated culture into fresh medium and growth for 24 h at 37°C.