TABLE 8.
Frequency of amino acid substitutions detected in the QRDR, including GyrA, GyrB, ParC, and ParE in fluoroquinolone-resistant MRSA and MSSA clinical isolates from blood culturea,c
| GyrA | ParC | ParE | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Amino acid substitutions | Total n (%) |
MRSA n (%) |
MSSA n (%) |
Amino acid substitutions | Total n (%) |
MRSA n (%) |
MSSA n (%) |
Amino acid substitutions | Total n (%) |
MRSA n (%) |
MSSA n (%) |
| S84L | 59 (94) | 57 (95) | 2 (67) | S80F | 53 (84) | 51 (81) | 2 (67) | P451S | 16 (25) | 16 (27) | 0 (0) |
| S85P | 14 (22) | 13 (22) | 1 (33) | S80Y | 8 (13) | 8 (13) | 0 (0) | N402T | 7 (11) | 7 (12) | 0 (0) |
| M121C | 8 (13) | 8 (13) | 0 (0) | E84K | 8 (13) | 8 (13) | 0 (0) | L440F | 1 (2) | 1 (2) | 0 (0) |
| I175M | 7 (11) | 7 (12) | 0 (0) | E84G | 4 (6) | 4 (6) | 0 (0) | D432V | 1 (2) | 1 (2) | 0 (0) |
| N182I | 6 (11) | 6 (10) | 0 (0) | I195M | 1 (2) | 1 (2) | 0 (0) | NDb | 41 (65) | 38 (63) | 3 (100) |
| I131S | 5 (8) | 5 (8) | 0 (0) | N203I | 1 (2) | 1 (2) | 0 (0) | ||||
| L188* | 4 (6) | 4 (7) | 0 (0) | P153A | 1 (2) | 1 | 0 (0) | ||||
| E88K | 3 (5) | 3 (5) | 0 (0) | Q204H | 1 (2) | 1 (2) | 0 (0) | ||||
| A176G | 2 (3) | 2 (3) | 0 (0) | R20D | 1 (2) | 1 (2) | 0 (0) | ||||
| L167S | 2 (3) | 2 (3) | 0 (0) | ND | 2 (2) | 1 (2) | 1 (33) | ||||
| D151* | 1 (2) | 1 (2) | 0 (0) | ||||||||
| D151M | 1 (2) | 1(2) | 0 (0) | ||||||||
| L188Q | 1(2) | 1 (2) | 0 (0) | ||||||||
| M210E | 1 (2) | 1 (2) | 0 (0) | ||||||||
| ND | 3 (5) | 2 (3) | 1 (33) | ||||||||
a
"*” indicates stop codon.
b
ND, not detected.
c
Empty cells indicate that the corresponding amino acid substitution was not observed for that gene, as substitution types vary among GyrA, ParC, and ParE.