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. 2021 Sep 17;65(10):e01069-21. doi: 10.1128/AAC.01069-21

TABLE 2.

Summary of AST MIC and MBEC values determined for E. coli KAM32 transformed with various qac vectors and grown as planktonic (broth), colony (agar spot), and biofilm (MBEC) cultures for 24 h at 37°C

Condition and vectord MIC or MBEC (μg/ml)a
CPC CET BZK DDAB CDEB CTAB DOM ET AC MV CHX ERY TOB
MICb
    Agar (n = 3)
        pMS119EH 2 1 1 0.5 2 4 2 12 1 80 4 2 4
        pEmrE 8 4 2 2 8 8 4 256 8 160 4 2 2
        pQacE 8 8 4 1 8 8 4 32 4 80 4 2 2
        pQacEΔ1 2 4 1 0.5 4 4 2 8 4 80 4 2 4
        pQacF 8 8 4 2 8 8 4 8 4 80 4 2 8
        pQacG 8 8 4 2 8 4 2 8 1 80 4 2 8
        pQacH 8 4 4 2 8 8 8 32 4 80 4 2 4
    Broth (n = 3)
        pMS119EH 1.2 2 2 0.5 2 1 1 16 8 80 1 1–2 2
        pEmrE 2.4 4 2 1 2 1 1–2 64 64 320 1 1 2–4
        pQacE 1.2–2.4 4 2 1 2 1 1–2 64 16–32 80 1 1–2 2
        pQacEΔ1 1.2–2.4 2 2 0.5 2 1 1 32 8 80 1 1 2
        pQacF 1.2–2.4 8 4 2 2 2 1–2 16 8 80 1 2 2–4
        pQacG 2.4 4 4 2 4 2 1–2 16 8 160 1 2 2–4
        pQacH 1.2–2.4 4 4 2 4 1 1–2 32 16–32 160 1 1–2 2–4
    MBEC (n = 6)c
        pMS119EH 128 16 32 16 16 8 8 64 32 4,096 32 64 2–4
        pEmrE 32 32 16 16 64 8 26 512 256 1,6384 64 128 8–16
        pQacE 32 32 16 8 32–64 8 16 256 128–256 1,6384 64 128 8
        pQacEΔ1 64 64 32 6 16 4 8 64 64 1,6384 64 64–128 8
        pQacF 64 64 32 16 32–64 4 32 256 64 4,096 32 64 16
        pQacG 256 128 32 16 32–64 16 8 32–64 16–32 1,6384 64 64 8
        pQacH 32 16 16 16 32–64 16 3 341 256 4,096 64 128 16–32
a

Antimicrobial abbreviations: CPC, cetylpyridinium chloride; CET, cetrimide bromide; BZK, benzalkonium chloride; DDAB, didecyldimethylammonium bromide; CDEB, cetyldimethylethylammonium bromide; CTAB, cetyltrimethylammonium bromide; DOM, domiphen bromide; ET, ethidium bromide; MV, methyl viologen dichloride; CHX, chlorhexidine dichloride; AC, acriflavine; ERY, erythromycin; TOB, tobramycin. Boldface numbers indicate ≤4- or ≥4-fold changes in MIC/MBEC AST values compared to pMS119EH transformants under the same AST growth conditions.

b

AST involved 10−4 dilutions of plasmid-transformed cultures adjusted to an optical density at 600 nm of 1.0 as the starting inoculum in Luria-Bertani medium with 100 μg/ml ampicillin and 0.05 mM isopropyl β-d-1-thiogalactopyranoside (IPTG).

c

Shown are results from 24-h biofilms grown on the MBEC device pegged lid incubated with drug for 24 h in LB broth prior to AST.

d

All genes were directionally cloned in the multiple-cloning site of pMS119EH at 5' XbaI and 3' HindIII restriction sites.