Table 2.
Antibiotic resistance genes in the 82 vancomycin-resistant enterococcal strains.
| Antibiotics | Gene | Total (n = 82) | LKM (n = 44) | HCT (n = 23) | ICU (n = 15) |
|---|---|---|---|---|---|
| Vancomycin, n (%) | vanA | 81 (99) | 44 (100) | 22 (96) | 15 (100) |
| vanA and vanB | 1 (1) | 0 | 1 (4) | 0 | |
| Daptomycin, n (%) * | 28 (34) | 11 (25) | 9 (39) | 8 (53) | |
| Linezolid, n (%) † | optrA, poxtA, cfr, eatAv, 23S rDNA | 11 (13) | 6 (14) | 4 (17) | 1 (7) |
| Macrolides, n (%) | erm(B) | 67 (82) | 36 (82) | 18 (78) | 13 (87) |
| Macrolides, lincosamides, and streptogramin B, n (%) | msr(C) | 81 (99) | 44 (100) | 22 (96) | 15 (100) |
| Teicoplanin, n (%) ** | vanHAX, vanR/vanS | 78 (95) | 43 (98) | 22 (96) | 13 (87) |
| Tetracyclines, n (%) | |||||
| Tetracyclines only | tet(L) | 37 (45) | 17 (39) | 12 (52) | 8 (53) |
| Minocycline and tetracyclines | tet(M) | 63 (77) | 35 (80) | 16 (70) | 12 (80) |
| Aminoglycosides, n (%) | |||||
| Streptomycin | ant(6)-Ia | 51 (62) | 31 (71) | 9 (39) | 11 (73) |
| Kanamycin, neomycin | aph(3’)-III | 64 (78) | 36 (82) | 17 (74) | 11 (73) |
| Trimethoprim, n (%) | dfrG | 22 (27) | 9 (21) | 6 (26) | 7 (47) |
Abbreviations: LKM, leukemia; HCT, hematopoietic cell transplant; ICU, intensive care unit. * Daptomycin resistance was conferred by the presence of amino-acid substitutions in predominant LiaFSR proteins; threonine to alanine on position 120 of the LiaS protein sequence, tryptophan to cysteine on position 73 the LiaR sequence, histidine to arginine on position 215, and aspartic acid to asparagine on position 27. † Linezolid resistance was conferred by the presence of the optrA, poxtA, and cfr genes; mutations in the 23S rDNA genes; laboratory susceptibility testing, with a minimum inhibitory concentration range of 8–64 µg/mL. ** Teicoplanin resistance was conferred to the presence of the vanHAX gene operon and the VanR/VanS two-component system [18,19].