Introduction
Materials and methods
Species identification, antimicrobial susceptibility testing and analysis of vancomycin resistance determinants
Antimicrobial agent/phenotype |
E. faecium
|
E. faecalis
| ||||
---|---|---|---|---|---|---|
R (%) | MIC50
| MIC90
| R (%) | MIC50
| MIC90
| |
Linezolid | 41 (100) | 16 | 64 | 8 (100) | 16 | 32 |
Tedizolid | 41 (100) | 4 | >32 | 8 (100) | 4 | 16 |
Penicillin | 41 (100) | 256 | >256 | 1 (12.5) | 4 | 16 |
Ampicillin | 41 (100) | 256 | >256 | 0 | 0.5 | 1.0 |
HLGR | 33 (80.5) | >1024 | >1024 | 7 (87.5) | >1024 | >1024 |
HLSR | 31 (75.6) | 2048 | >2048 | 8 (100) | >2048 | >2048 |
Vancomycin | 37 (90.2) | >256 | >256 | 0 | 2.0 | 4.0 |
Teicoplanin | 34 (82.9) | 64 | 256 | 0 | 0.25 | 0.5 |
Tetracycline | 12 (29.3) | 0.25 | 32 | 8 (100) | 64 | 128 |
Erythromycin | 31 (75.6) | 256 | >256 | 8 (100) | >256 | >256 |
Tigecycline | 0 | 0.25 | 0.25 | 0 | 0.25 | 0.25 |
Ciprofloxacin | 41 (100) | 256 | >256 | 8 (100) | 128 | 128 |
Chloramphenicol | 22 (53.6) | 32 | 64 | 6 (75.0) | 64 | 128 |
Rifampin | 39 (95.2) | 128 | >256 | 6 (75.0) | 8 | 64 |
Daptomycin | 0 | 2 | 4 | 0 | 1 | 2 |
Quinupristin–dalfopristin | 0 | 0.5 | 1 | nd | nd | nd |
Molecular typing of isolates
Detection and analysis of linezolid resistance determinants
Conjugation experiments
Genomic sequencing and plasmidome of optrA–E. faecalis
Growth experiments
Nucleotide accession numbers
Results
Bacterial isolates: epidemiological data, species, antimicrobial susceptibility and clonal relatedness
A.E. faecium
| |||||||||||||||
Centre | Year of isolationa
| ST | Lineage | MT | MIC (mg/L) | Linezolid resistance determinants | Tn1546 typed
| ||||||||
Linezolid | Tedizolid | 1b
| 2b
| 3b
| 4b
| 5b
| 6b
| Mutated copies of 23S rDNA |
optrA
| ||||||
GDA | 2013 (1) | 17 | 17/18 | 7 | 128 | >32 | − | − | − | + | − | + | 2 | − | |
2013 (1) | 117 | 17/18 | 527 | 128 | >32 | + | − | − | − | + | + | 3 | − | ||
2013 (2) | 202 | 17/18 | 1 | 16–32 | 8–16 | + | − | − | − | + | + | 3 | − | ||
2013 (7) | 117 | 17/18 | 12 | 32–64 | 8–32 | + | − | − | − | + | + | 3 | − | A | |
2014 (1) | 117 | 17/18 | 12 | 32 | 4 | + | − | − | − | + | + | 3 | − | A | |
LEG | 2011 (1) | 877 | 17/18 | 12 | 16 | >32 | − | − | − | + | + | + | 3 | − | |
LODZ1 | 2012 (1) | 117 | 17/18 | 12 | 8 | 4 | − | − | − | + | − | + | 2 | − | A |
LODZ2 | 2015 (1) | 117 | 17/18 | 12 | 8 | 2 | − | − | + | + | − | + | 3 | − | A |
POZ1 | 2011 (1) | 202 | 17/18 | 11 | 8 | 4 | − | − | − | − | + | + | 2 | − | |
POZ2 | 2012 (4) | 117 | 17/18 | 12 | 8 | 8 | − | − | + | − | + | + | 3 | − | |
8 | 8 | − | − | + | − | + | + | 3 | [+] | ||||||
8 | 1 | − | + | + | − | + | + | 4 | − | ||||||
8 | 4 | − | − | + | − | + | + | 3 | [+] | ||||||
POZ3 | 2015 (1) | 18 | 17/18 | 10 | 32 | 4 | + | − | − | + | + | + | 4 | − | |
SOC | 2014 (1) | 117 | 17/18 | 12 | 32 | 1 | − | − | − | + | − | + | 2 | − | B |
WLO | 2015 (5) | 203 | 78 | 159 | 16–32 | 2–4 | − | − | + | − | + | + | 3 | − | |
WRO1 | 2013 (1) | 17 | 17/18 | 1 | 16 | 4 | − | − | − | + | − | + | 2c
| [+] | |
WRO2 | 2014 (2) | 117 | 17/18 | 12 | 32 | 2 | − | − | + | − | − | + | 2 | − | C |
117 | 17/18 | 12 | 16 | 16 | + | + | + | + | − | + | 5 | − | C | ||
WAR1 | 2013 (1) | 78 | 78 | 282 | 16 | 16 | − | + | − | − | + | + | 3 | − | |
WAR2 | 2013 (1) | 412 | 78 | 159 | 8 | 2 | − | − | − | + | − | − | 1 | − | |
WAR3 | 2011 (1) | 880 | 78 | 1 | 16 | 8 | − | − | + | − | + | + | 3 | − | |
2011 (1) | 80 | 17/18 | 1 | 8 | 4 | − | − | − | − | + | + | 2 | − | ||
2014 (1) | 80 | 17/18 | 1 | 32 | 4 | − | − | − | − | − | − | 0 | − | ||
2014 (1) | 117 | 17/18 | 159 | 8 | 2 | − | − | − | − | − | + | 1c
| − | ||
WAR4 | 2010 (1) | 78 | 78 | 159 | 16 | 4 | − | + | − | + | + | + | 4 | − | |
WAR5 | 2008 (1) | 192 | 78 | 159 | 16 | 2 | − | − | − | − | + | + | 2 | − | |
2014 (1) | 117 | 17/18 | 12 | 32 | 16 | + | − | + | + | + | + | 5 | − | C | |
2015 (2) | 117 | 17/18 | 12 | 128 | >32 | + | − | + | + | + | + | 5 | − | A | |
B. E. faecalis
| |||||||||||||||
Centre | Year of isolation a
| ST | CC | MIC (mg/L) | Linezolid resistance determinants | ||||||||||
Linezolid | Tedizolid | 1b
| 2b
| 3b
| 4b
| Mutated copies of 23S rDNA |
optrA
| ||||||||
POZ1 | 2012 (4) | 6 | 6 | 8–16 | 4–8 | + | + | − | − | 2 | − | ||||
2012 (1) | 6 | 6 | 32 | 16 | + | + | − | + | 3 | − | |||||
RZE | 2015 (1) | 6 | 6 | 32 | 4 | + | − | − | + | 2 | − | ||||
KIEL | 2012 (1) | 116 | 116 | 32 | 16 | − | − | − | − | 0 | + | ||||
BYD | 2013 (1) | 116 | 116 | 16 | 4 | − | − | − | − | 0 | + |