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. 2020 Aug 20;64(9):e00533-20. doi: 10.1128/AAC.00533-20

TABLE 1.

Microbiological activities of gentamicin congeners against Gram-negative wild-type strains and an isogenic E. coli panel that harbored key aminoglycoside-modifying enzymes

Panel Geometric mean MIC value (mg/liter)a
Mixb C1a C2 C2a C1
Wild type
    E. coli ATCC 25922 0.5 0.5 0.5 0.5 0.5
    P. aeruginosa ATCC 27853 0.5 0.25 0.25 0.25 1
    A. baumannii M2c 1 0.25 0.5 0.5 2
Isogenice
    E. coli ATCC 700926 + empty vectord 0.25 0.125 0.125 0.125 0.125
    E. coli ATCC 700926 + aac(6′)-Ib 1 4 0.5 32 0.25
    E. coli ATCC 700926 + aac(3)-III 4 2 4 4 32
    E. coli ATCC 700926 + aph(3′)-Ia 0.5 0.125 0.25 0.25 0.5
a

MIC values are the geometric mean of multiple independent measurements rounded to the nearest CLSI standard dilution increment.

b

“Mix” refers to batch of laboratory-grade gentamicin used to purify the gentamicin congeners.

c

Wild-type A. baumannii M2 has been previously characterized (34).

d

Parent E. coli strain containing the empty version of the pBBR1MCS-4 vector (35) used to carry the aminoglycoside-modifying enzyme genes in the isogenic panel.

e

Nine additional isogenic E. coli isolates with either aac(6′)-aph(2′′), aph(3′)-II, aph(3′)-III, aph(3′)-IV, aph(3′)-V, aph(3′)-VII, aac(2′)-I, aac(3)-I, or aac(3)-X were also tested, and the MICs for each congener fell within ±1 log2 dilution of the gentamicin “Mix” MIC.