TABLE 4.
Isolates with elevated or nonsusceptible linezolid MIC values observed during the 2011–2015 LEADER Program
| Organism | Yr | City | State | LZD MIC (μg/ml)a | Resistance mechanism(s) (mutation[s]) | PFGE typeb |
|---|---|---|---|---|---|---|
| S. aureus | 2011 | Akron | OH | 4 | cfr | SA4I |
| S. aureus | 2011 | Houston | TX | 8 | 23S rRNA (G2576T) | |
| S. aureus | 2011 | Long Beach | CA | 8 | cfr; 23S rRNA (G2576T) | SA146A |
| S. aureus | 2011 | Louisville | KY | 8 | cfr | |
| S. aureus | 2011 | Milwaukee | WI | 4 | L3 (ΔS145) | |
| S. aureus | 2012 | Indianapolis | IN | 4 | cfr | |
| S. aureus | 2012 | Maywood | IL | 4 | cfr | |
| S. aureus | 2012 | New York | NY | 32 | 23S rRNA (G2576T); L3 (ΔS145) | |
| S. aureus | 2013 | Detroit | MI | 8 | cfr | |
| S. aureus | 2013 | Long Beach | CA | 32 | cfr; 23S rRNA (G2576T); L3 (D159E, G152D) | SA146A |
| S. aureus | 2014 | Long Beach | CA | 8 | 23S rRNA (G2576T) | SA468A |
| S. aureus | 2014 | Long Beach | CA | 16 | cfr; 23S rRNA (G2576T); L3 (ΔH146, P151L) | SA468B |
| S. aureus | 2014 | New Orleans | LA | 4 | cfr | |
| S. aureus | 2015 | Long Beach | CA | 8 | 23S rRNA (G2576T) | SA468A |
| S. epidermidis | 2011 | Cleveland | OH | 32 | 23S rRNA (G2576T); L3 (M156T, H146P, G137S, F147Y); L4 (71G72 insc) | |
| S. epidermidis | 2011 | Hackensack | NJ | 64 | 23S rRNA (G2576T); L3 (V154L, M156T, H146R, G137D); L4 (71G72 ins) | |
| S. epidermidis | 2011 | Hershey | PA | 64 | 23S rRNA (G2576T); L3 (V154L, M156T, H146R) | SEPI453C |
| S. epidermidis | 2011 | Houston | TX | 64 | 23S rRNA (G2576T); L3 (M156T, H146P, G137S) | SEPI116D |
| S. epidermidis | 2011 | Houston | TX | 16 | L3 (V154L, H146Q, A157R); L4 (71G72 ins) | SEPI116E |
| S. epidermidis | 2011 | Memphis | TN | 128 | 23S rRNA (G2576T); L3 (V154L, M156T, H146R); L4 (71G72 ins) | SEPI436A |
| S. epidermidis | 2011 | Memphis | TN | 128 | 23S rRNA (G2576T); L3 (V154L, M156T, H146R); L4 (71G72 ins) | SEPI436A |
| S. epidermidis | 2011 | New Brunswick | NJ | 64 | 23S rRNA (G2576T) | SEPI129I |
| S. epidermidis | 2011 | New Orleans | LA | 64 | 23S rRNA (G2576T) | SEPI448F |
| S. epidermidis | 2012 | Burlington | MA | 16 | L3 (V154L, A157R); L4 (71G72 ins) | |
| S. epidermidis | 2012 | Detroit | MI | 128 | 23S rRNA (G2576T); L3 (G137S, H146P, F147Y, M156T); L4 (71G72 ins) | SEPI3K |
| S. epidermidis | 2012 | Memphis | TN | 16 | L3 (H146Q, V154L, A157R); L4 (71G72 ins) | SEPI412C |
| S. epidermidis | 2012 | New Brunswick | NJ | 32 | 23S rRNA (G2576T); L3 (H146R, V154L, M156T); L4 (71G72 ins) | SEPI129B |
| S. epidermidis | 2012 | Philadelphia | PA | 16 | L3 (H146Q, V154L, A157R); L4 (71G72 ins) | |
| S. epidermidis | 2012 | Winston-Salem | NC | 128 | 23S rRNA (G2576T); L3 (G137S, H146P, M156T); L4 (71G72 ins) | SEPI454E |
| S. epidermidis | 2012 | Winston-Salem | NC | 128 | 23S rRNA (G2576T); L3 (G137S, H146P, M156T); L4 (71G72 ins) | SEPI454E |
| S. epidermidis | 2013 | Detroit | MI | 128 | 23S rRNA (G2576T); L3 (G137S, H146P, M156T); L4 (71G72 ins) | SEPI3K |
| S. epidermidis | 2013 | Houston | TX | 64 | 23S rRNA (G2576T); L3 (H146R, M156T); L4 (71G72 ins) | SEPI116F |
| S. epidermidis | 2013 | Winston-Salem | NC | 32 | 23S rRNA (G2576T); L3 (H146P, M156T) | SEPI454E |
| S. epidermidis | 2014 | Houston | TX | 64 | 23S rRNA (G2576T); L3 (G137S, H146P, M156T); L4 (71G72 ins) | SEPI116D |
| S. epidermidis | 2014 | Houston | TX | 128 | cfr; L3 (H146Q, V154L, A157R); L4 (71G72 ins) | SEPI116E |
| S. epidermidis | 2014 | Long Beach | CA | 128 | cfr; L3 (G137S, H146Q, V154L, A157R); L4 (71G72 ins) | SEPI468B |
| S. epidermidis | 2014 | Memphis | TN | >128 | cfr; 23S rRNA (G2576T); L4 (G137S, H146P, F147Y, M156T); L4 (71G72 ins) | SEPI412F |
| S. epidermidis | 2014 | San Francisco | CA | >128 | cfr; L3 (H146Q, V154L, A157R); L4 (71G72 ins) | SEPI470A |
| S. epidermidis | 2015 | Houston | TX | 128 | cfr; 23S rRNA (C2534T); L3 (V154L, A157R); L4 (71G72 ins) | SEPI116E |
| S. epidermidis | 2015 | Houston | TX | >128 | cfr; 23S rRNA (C2534T); L3 (H146Q, V154L, A157R) | SEPI116E |
| S. epidermidis | 2015 | Houston | TX | 16 | 23S rRNA (C2534T); L3 (H146Q, V154L, A157R); L4 (71G72 ins) | SEPI116E1 |
| S. epidermidis | 2015 | Houston | TX | 16 | L3 (V96D, H146Q, V154L, A157R); L4 (71G72 ins) | SEPI116G |
| S. epidermidis | 2015 | Long Beach | CA | 16 | 23S rRNA (G2576T); L3 (V154L, M156T) | SEPI468C |
| S. epidermidis | 2015 | Memphis | KY | 128 | 23S rRNA (G2576T); L3 (Q136L, H146R, M156T); L4 (71G72 ins) | SEPI412F |
| S. epidermidis | 2015 | Winston-Salem | NC | 16 | 23S rRNA (G2576T); L3 (H146P, M156T) | SEPI454E |
| S. hominis | 2014 | Seattle | WA | 8 | cfr; L3 (M169L) | |
| S. sanguinis | 2013 | Aurora | CO | 4 | 23S rRNA (G2576T); L4 (A22T) | |
| E. faecalis | 2012 | Wauwatosa | WI | 4 | 23S rRNA (G2576T) | |
| E. faecalis | 2013 | Hershey | PA | 8 | 23S rRNA (G2576T) | |
| E. faecalis | 2014 | Burlington | VT | 8 | optrA | |
| E. faecalis | 2015 | Milwaukee | WI | 4 | optrA | |
| E. faecium | 2012 | Houston | TX | 8 | 23S rRNA (G2576T) | EFM116B |
| E. faecium | 2012 | Lansing | MI | 8 | 23S rRNA (G2576T) | |
| E. faecium | 2012 | New Orleans | LA | 4 | 23S rRNA (G2576T) | EFM448A |
| E. faecium | 2012 | New Orleans | LA | 8 | cfr(B); 23S rRNA (G2576T) | EFM448B |
| E. faecium | 2013 | Akron | OH | 32 | 23S rRNA (G2576T) | |
| E. faecium | 2013 | Houston | TX | 16 | 23S rRNA (G2576T) | EFM116C |
| E. faecium | 2013 | Los Angeles | CA | 32 | 23S rRNA (G2576T) | EFM467A |
| E. faecium | 2013 | Maywood | IL | 8 | 23S rRNA (G2576T) | |
| E. faecium | 2013 | New Orleans | LA | 8 | cfr(B); 23S rRNA (G2576T) | EFM448B |
| E. faecium | 2014 | Atlanta | GA | 8 | cfr(B); 23S rRNA (G2576T) | |
| E. faecium | 2014 | Charlottesville | VA | 4 | 23S rRNA (G2576T) | |
| E. faecium | 2014 | Fairbanks | AK | 8 | 23S rRNA (G2576T) | EFM461A |
| E. faecium | 2014 | Fairbanks | AK | 8 | 23S rRNA (G2576T) | EFM461A1 |
| E. faecium | 2014 | Los Angeles | CA | 16 | 23S rRNA (G2576T) | EFM467B |
| E. faecium | 2015 | Houston | TX | 8 | 23S rRNA (G2576T) | EFM116D |
| E. faecium | 2015 | Seattle | WA | 8 | 23S rRNA (G2576T); L3 (K95T) |
a
Preliminarily determined elevated MIC values (≥4 μg/ml) were confirmed by using a customized frozen-form panel with an extended linezolid (LZD) dilution range (i.e., 1 to 128 μg/ml).
b
Pulsed-field gel electrophoresis (PFGE) types were assigned according to the organism code, the origin of the isolate (medical site number), a capital letter (type), and a number (subtype), when applicable. Only PFGE profiles from same species isolates recovered from the same medical site were compared. PFGE types that included more than 1 isolate representing clonal dissemination are in bold.
c
ins, insertion.