Skip to main content
. 2024 Oct 15;68(11):e00591-24. doi: 10.1128/aac.00591-24

TABLE 2.

Antimicrobial susceptibility testing results for E. faecalis, E. faecium, and E. lactis, including vancomycin-resistant E. faecalis and E. faecium, 2018–2019 DHQP Sentinel Surveillance system isolatesa

% Susceptible % Intermediate % Resistant MIC range (µg/mL) MIC50 (µg/mL) MIC90 (µg/mL)
E. faecalis (n = 205)
 Ampicillin 100.0 N/A 0.0 ≤0.25 to 2 1 1
 Penicillin 100.0 N/A 0.0 ≤0.25 to 8 2 4
 Vancomycin 92.2 0.0 7.8 0.5 to > 64 1 2
 Teicoplanin 92.2 0.0 7.8 ≤0.12 to > 64 0.5 1
 Daptomycin 80.0 18.0 2.0 ≤0.25 to 16 2 4
 Linezolid 98.0 0.0 2.0 ≤0.5 to 16 2 2
 Tedizolidb 98.0 N/A 2.0 ≤0.12 to 2 0.5 0.5
 Quinupristin/dalfopristinc N/A N/A N/A 0.5 to > 8 8 8
 Levofloxacin 77.1 0.0 22.9 0.5 to > 8 1 >8
 Doxycycline 45.9 47.3 6.8 ≤2 to 32 8 8
 Tigecyclined 100.0 N/A N/A 0.06 to 0.25 0.12 0.12
 Eravacyclineb,e 95.1 N/A 4.9 ≤0.016 to 0.12 0.06 0.06
 Chloramphenicol 89.3 1.5 9.3 ≤2 to > 32 4 16
 Gentamicinf 77.6 N/A 22.4 - - -
 Streptomycinf 83.4 N/A 16.6 - - -
VR E. faecalis (n = 16)
 Ampicillin 100.0 N/A 0.0 0.5 to 2 1 1
 Penicillin 100.0 N/A 0.0 2 to 8 4 4
 Vancomycin 0.0 0.0 100.0 >64 >64 >64
 Teicoplanin 0.0 0.0 100.0 32 to > 64 >64 >64
 Daptomycin 75.0 18.8 6.3 0.5 to 8 1 4
 Linezolid 81.3 0.0 18.8 ≤0.5 to 16 2 16
 Tedizolidb 81.3 N/A 18.8 ≤0.12 to 2 0.25 2
 Quinupristin/dalfopristinc N/A N/A N/A 0.5 to > 8 8 8
 Levofloxacin 0.0 0.0 100.0 8 to > 8 >8 >8
 Doxycycline 75.0 25.0 0.0 ≤2 to 8 4 8
 Tigecyclined N/A N/A N/A 0.06 to 0.25 0.12 0.12
 Eravacyclineb,e 93.8 N/A 6.3 ≤0.016 to 0.12 0.06 0.06
 Chloramphenicol 62.5 18.8 18.8 8 to > 32 8 >32
 Gentamicinf 18.8 N/A 81.3 - - -
 Streptomycinf 68.8 N/A 31.3 - - -
E. faecium (n = 180)
 Ampicillin 7.2 N/A 92.8 ≤0.25 to > 32 >32 >32
 Penicillin 6.7 N/A 93.3 ≤0.25 to > 32 >32 >32
 Vancomycin 21.1 0.6 78.3 0.5 to > 64 >64 >64
 Teicoplanin 21.1 0.6 78.3 0.5 to > 64 >64 >64
 Daptomycing 94.4 N/A 5.6 ≤0.25 to 16 4 4
 Linezolid 98.3 1.1 0.6 ≤0.5 to 8 2 2
 Tedizolid N/A N/A N/A ≤0.12 to 1 0.5 0.5
 Quinupristin/dalfopristinh N/A N/A N/A 0.25 to 8 1 2
 Levofloxacin 5.0 2.8 92.2 1 to > 8 >8 >8
 Doxycycline 50.6 13.9 35.6 ≤2 to 32 4 16
 Tigecyclined N/A N/A N/A ≤0.03 to 0.5 0.06 0.12
 Eravacyclineb,e 88.3 N/A 11.7 ≤0.016 to > 0.25 0.06 0.12
 Chloramphenicol 87.2 11.1 1.7 4 to > 32 8 16
 Gentamicinf 88.9 N/A 11.1 - - -
 Streptomycinf 60.6 N/A 39.4 - - -
VR E. faecium (n = 141)
 Ampicillin 0.0 N/A 100.0 32 to > 32 >32 >32
 Penicillin 0.0 N/A 100.0 >32 >32 >32
 Vancomycin 0.0 0.0 100.0 >64 >64 >64
 Teicoplanin 0.0 0.7 99.3 16 to > 64 >64 >64
 Daptomycing 95.7 N/A 4.3 ≤0.25 to 16 4 4
 Linezolid 98.6 0.7 0.7 ≤0.5 to 8 2 2
 Tedizolid N/A N/A N/A ≤0.12 to 1 0.5 0.5
 Quinupristin/dalfopristinh 89.4 3.5 7.1 0.25 to 8 1 2
 Levofloxacin 0.0 0.0 100.0 >8 >8 >8
 Doxycycline 52.5 13.5 34.0 ≤2 to 32 4 16
 Tigecyclined N/A N/A N/A ≤0.03 to 0.5 0.06 0.12
 Eravacyclineb, e 88.7 N/A 11.3 ≤0.016 to > 0.25 0.06 0.12
 Chloramphenicol 87.2 11.3 1.4 4 to > 32 8 16
 Gentamicinf 90.8 N/A 9.2 - - -
 Streptomycinf 58.9 N/A 41.1 - - -
E. lactis (n = 19)
 Ampicillin 100.0 N/A 0.0 ≤0.25 to 2 1 2
 Penicillin 100.0 N/A 0.0 ≤0.25 to 8 4 8
 Vancomycin 100.0 0.0 0.0 0.5 to 1 0.5 1
 Teicoplanin 100.0 0.0 0.0 0.5 to 2 1 1
 Daptomycing 94.7 N/A 5.3 0.5 to 8 4 4
 Linezolid 100.0 0.0 0.0 1 to 2 2 2
 Tedizolid N/A N/A N/A 0.25 to 0.5 0.5 0.5
 Quinupristin/dalfopristinh N/A N/A N/A 1 to 4 2 2
 Levofloxacin 89.5 5.3 5.3 0.5 to > 8 1 4
 Doxycycline 94.7 0.0 5.3 ≤2 to 16 ≤2 ≤2
 Tigecyclined N/A N/A N/A 0.06 0.06 0.06
 Eravacyclineb, e 100.0 N/A 0.0 0.03 to 0.06 0.06 0.06
 Chloramphenicol 94.7 5.3 0.0 4 to 16 4 8
 Gentamicinf 100.0 N/A 0.0 - - -
 Streptomycinf 94.7 N/A 5.3 - - -
a

N/A, isolates were tested, but no breakpoints were available; VR, vancomycin resistant.

b

For tedizolid and eravacycline, % nonsusceptible is reported as there is no resistant category.

c

E. faecalis is intrinsically resistant to quinupristin/dalfopristin.

d

U.S. FDA MIC susceptibility test interpretive criteria (breakpoint) for tigecycline (susceptible ≤0.25 μg/mL) is only available for vancomycin-susceptible E. faecalis. The FDA breakpoint for tigecycline was only applied to vancomycin-susceptible E. faecalis isolates (n=189). CLSI breakpoints are not established.

e

U.S. FDA MIC susceptibility test interpretive criteria (breakpoint) for eravacycline (susceptible ≤0.06 μg/mL) was used as CLSI breakpoints are not established.

f

E. faecalis and E. faecium isolates are intrinsically resistant to aminoglycosides. High-level gentamicin resistance and high-level streptomycin resistance were tested using 500 µg/mL and 1000 µg/mL of the antibiotic, respectively. Susceptibility implies synergy between the aminoglycoside and the cell wall active agent and resistance implies no synergy between the aminoglycoside and the cell wall active agent; therefore, MIC range, MIC50, and MIC90 are indicated as (-).

g

For daptomycin and E. faecium/E.lactis, there is no susceptible breakpoint so susceptible-dose dependent (SDD) is reported. Given the close genetic relationship between E. faecium and E. lactis, E. faecium daptomycin breakpoints were applied to the E. lactis isolates.

h

For quinupristin/dalfopristin, CLSI guidance is to report only on vancomycin-resistant E. faecium.