Table 1.
Clinical, phenotypic and genotypic data for the linezolid-resistant Enterococci isolates investigated
| Isolate no. | Organism | Isolation year | Hospitalb | Isolation site | STc | MICs (mg/L)a | Linezolid resistance genes | 23S rRNA gene mutations | Other resistance genes | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| LNZ | P | AMP | VAN | TEC | DAP | TGC | LVX | ERY | HLG | Antibiotic resistance profiles | |||||||||
| 29462 | E. faecalis | 2009 | ZRYH | urine | 86 | 8 | 4 | <=2 | 2 | <=0.125 | 0.5 | 0.06 | 8 | > 4 | R | LVX, ERY | optrA | – | emeA, ANT(6)-Ia, AAC(6′)-Ie-APH(2″)-Ia, dfrG, dfrE, lsaA, fexA, cat, efrB, efrA, ermB, tetM, tet(L) |
| ZJ11066 | E. faecalis | 2011 | ZJFY | blood | 116 | 8 | 2 | <=2 | 1 | 0.125 | 0.5 | 0.12 | 8 | > 4 | R | LVX, ERY | optrA | – | emeA, APH(3′)-IIIa, AAC(6′)-Ie-APH(2″)-Ia, dfrF, dfrG, dfrE, lnuG, lsaA, fexA, efrA, efrB, ermB, ermA1, tet(L), tetM |
| JS11041 | E. faecium | 2011 | JSRM | urine | ND | 8 | > = 64 | > = 32 | 0.5 | 0.25 | 2 | 0.06 | 8 | > 4 | R | P, AMP, LVX, ERY | – | – | ND |
| 19113 | E. faecalis | 2011 | SZRM | bile | ND | 8 | > = 64 | > = 32 | 2 | <=0.125 | 0.5 | 0.06 | 1 | > 4 | R | P, AMP, LVX, ERY | – | – | ND |
| ZJLRE1 | E. faecium | 2011 | ZJFE | blood | ND | 16 | > = 64 | > = 32 | 1 | 0.5 | 1 | 0.06 | 8 | > 4 | R | P, AMP, LVX, ERY | – | G2658 T | ND |
| 1207_26W003 | E. faecalis | 2012 | BJRM | urine | 476 | 4 | 2 | <=2 | 1 | 0.12 | 0.5 | 0.06 | 8 | > 4 | R | LVX, ERY | optrA | – | emeA, APH(3′)-IIIa, AAC(6′)-Ie-APH(2″)-Ia, aad(6), ANT(9)-Ia, dfrG, dfrE, lnuB, lsaE, lsaA, mdtF, SAT-4, cat, fexA, efrB, efrA, ermA1, ermB, tet(L), tetM |
| 1203_10W003 | E. faecalis | 2012 | BJRM | urine | 480 | 8 | 2 | <=2 | 1 | 0.12 | 0.5 | 0.06 | 8 | > 4 | R | LVX, ERY | optrA | – | emeA, AAC(6′)-Ie-APH(2″)-Ia, APH(3′)-IIIa, aad(6), ANT(6)-Ia, dfrG, dfrE, lnuB, lsaE, lsaA, SAT-4, cat, fexA, efrA, efrB, ermB, ermA1, tetM, tet(L) |
| 19677 | E. faecalis | 2012 | SZRM | blood | 59 | 8 | 2 | <=2 | 0.5 | 0.12 | 0.5 | 0.12 | 0.03 | > 4 | R | ERY | optrA | – | emeA, dfrE, lsaA, fexA, efrA, efrB, ermA1, tetM, tet(L) |
| 19506 | E. faecium | 2012 | SZRM | wound | 18 | 16 | > = 64 | > = 32 | 0.5 | 0.25 | 2 | 0.06 | 8 | > 4 | S | P, AMP, LVX, ERY | optrA | – | AAC(6′)-Ii, dfrG, efmA, msrC, fexA, ermA1 |
| 1202_13E004 | E. faecalis | 2012 | BJRM | wound | 416 | 16 | 8 | <=2 | 2 | <=0.125 | 0.5 | 0.12 | 8 | > 4 | R | LVX, ERY | optrA | – | emeA, ANT(6)-Ia, AAC(6′)-Ie-APH(2″)-Ia, dfrG, dfrE, lsaA, fexA, efrB, efrA, ermB, ermA1, tet(L), tetM |
| 1202_21W014 | E. faecalis | 2012 | BJRM | urine | 21 | 8 | 4 | <=2 | 2 | <=0.125 | 0.5 | 0.12 | 8 | > 4 | R | LVX, ERY | optrA | – | emeA, AAC(6′)-Ie-APH(2″)-Ia, aad(6), ANT(6)-Ia, dfrG, dfrE, lnuG, lsaA, SAT-4, fexA, cat, efrA, efrB, ermB, tet(L) |
| SZ21494 | E. faecalis | 2012 | SZRM | wound | 67 | 8 | 4 | <=2 | 1 | <=0.125 | 1 | 0.06 | 1 | > 4 | S | ERY | optrA | – | emeA, dfrE, dfrG, lnuG, lsaA, fexA, cat, efrA, efrB, ermB, ermA1, tetM, tet(L) |
| XM2013_71028 | E. faecalis | 2013 | XMDY | wound | 16 | 8 | 2 | <=2 | 1 | <=0.125 | 1 | 0.06 | 0.5 | > 4 | R | ERY | optrA | – | emeA, APH(3′)-IIIa, AAC(6′)-Ie-APH(2″)-Ia, ANT(9)-Ia, aad(6), dfrG, dfrE, lnuB, lsaE, lsaA, SAT-4, fexA, cat, efrB, efrA, ermB, ermA1, tetM |
| XM2013_42321 | E. faecalis | 2013 | XMDY | urine | 585 | 16 | 4 | <=2 | 1 | <=0.125 | 0.5 | 0.06 | 8 | > 4 | R | LVX, ERY | optrA | – | emeA, APH(3′)-IIIa, AAC(6′)-Ie-APH(2″)-Ia, aad(6), ANT(9)-Ia, dfrE, dfrG, lmrD, lnuB, lsaE, lsaA, SAT-4, cat, fexA, efrB, efrA, ermB, tetM, tet(L) |
| TZ2 | E. faecalis | 2013 | TZSY | blood | 476 | 8 | 2 | <=2 | 1 | <=0.125 | 0.5 | 0.12 | 8 | > 4 | R | LVX, ERY | optrA | – | emeA, AAC(6′)-Ie-APH(2″)-Ia, APH(3′)-IIIa, aad(6), ANT(6)-Ia, dfrG, dfrE, lsaA, SAT-4, fexA, cat, efrB, efrA, ermA1, ermB, tet(L), tetM |
| WHXH | E. faecalis | 2013 | WHDS | blood | 476 | 8 | 4 | <=2 | 2 | <=0.125 | 0.5 | 0.12 | 8 | > 4 | S | LVX, ERY | optrA | – | emeA, AAC(6′)-Ie-APH(2″)-Ia, APH(3′)-IIIa, aad(6), ANT(9)-Ia, dfrE, dfrG, lnuB, lsaE, lsaA, SAT-4, cat, fexA, efrB, efrA, ermB, tetM, tet(C), tet(L) |
aMICs, the minimal inhibitory concentrations; LNZ, linezolid, susceptible (S): ≤ 2 mg/L, intermediate (I): 4 mg/L, resistant (R): ≥ 8 mg/L; P, penicillin, S: ≤ 2 mg/L, R: ≥ 8 mg/L; AMP, ampicillin, S: ≤ 2 mg/L, R: ≥ 8 mg/L; VAN, vancomycin, S: ≤ 4 mg/L, I: 8–16 mg/L, R: ≥ 32 mg/L; TEC, teicoplanin, S: ≤ 8 mg/L, I: 16 mg/L, R: ≥ 32 mg/L; DAP, S: ≤ 1 mg/L, susceptible-dose dependent (SDD): 2–4 mg/L, R: ≥ 8 mg/L; TGC, tigecycline, no breakpoint in CLSI M100; LVX, levofloxacin, S: ≤ 2 mg/L, I: 4 mg/L, R: ≥ 8 mg/L; ERY, erythromycin, S: ≤ 0.5 mg/L, I: 1–4 mg/L, R: ≥ 8 mg/L; HLG, high-level gentamycin (500 mg/L); −, negative; ND, not determined
bZRYH, China-Japan Friendship Hospital; ZJFY, 1st Affiliated Hospital of Zhejiang University; JSRM, Jiangsu Province Hospital; SZRM, Shenzhen People’s Hospital; ZJFE, 2nd Affiliated Hospital of Zhejiang University; BJRM, Peking University People’s Hospital; XMDY, 1st Affiliated Hospital of Xiamen University; TZSY, Taizhou Hospital of Zhejiang Province; WHDS, Wuhan Fourth Hospital
cST sequence type, ND not determined