Volume 15, Number 6—June 2009
Research
Changes in Fluoroquinolone-Resistant Streptococcus pneumonia after 7-Valent Conjugate Vaccination, Spain
, Carmen Ardanuy, Luz Balsalobre, Emilio Pérez-Trallero, Jose M. Marimón, Asunción Fenoll, and Josefina Liñares
Table 2
Fluoroquinolone MICs of 30 low-level resistant Streptococcus pneumoniae isolates and 5 laboratory strains and amino acid changes in their DNA topoisomerase IV and gyrase genes, Spain, 2006*
| No. isolates | Amino acid substitution |
Efflux phenotype† | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| parC |
parE |
gyrA |
MIC, μg/mL |
|||||||||||
| S79 | S80 | D83 | D435 | E474 | S81 | E85 | CIP | LVX | MXF | |||||
| 1 | – | – | – | – | – | – | – | 4 | 1 | 0.12 | None | |||
| 3 | – | – | – | – | – | – | – | 4–8 | 2 | 0.5 | CIP | |||
| 1 | –‡ | –‡ | –‡ | –‡ | –‡ | –‡ | –‡ | 8 | 4 | 0.5 | CIP | |||
| 9 | F | – | – | – | – | – | – | 4–8 | 1–2 | 0.25–0.50 | None | |||
| 3 | F | – | – | – | – | – | – | 4–8 | 2 | 0.12–0.25 | CIP | |||
| 1 | F | – | – | – | – | –‡ | –‡ | 8 | 1 | 0.12 | None | |||
| 1 | F‡ | –‡* | –‡ | –‡ | –‡ | –‡ | –‡ | 8 | 2 | 0.12 | CIP, LVX | |||
| 5 | Y | – | – | – | – | – | – | 4–8 | 2 | 0.12–0.25 | None | |||
| 1 | Y | – | – | – | – | – | – | 4 | 2 | 0.25 | CIP | |||
| 1 | – | – | N | – | – | – | – | 16 | 4 | 0.5 | None | |||
| 1 | – | – | N | – | – | – | – | 4 | 2 | 0.12 | CIP | |||
| 1 | – | – | Y | – | – | – | – | 4 | 1 | 0.5 | None | |||
| 1 | – | – | Y | – | – | – | – | 8 | 2 | 0.5 | CIP | |||
| 1 |
– |
– |
– |
N |
– |
– |
– |
8 |
2 |
0.12 |
None |
|||
| Laboratory strains§ | ||||||||||||||
| R6 | 0.5 | 0.25 | 0.12 | None | ||||||||||
| R6CS80P | – | P | – | – | – | – | – | 2 | 1 | 0.25 | None | |||
| T1 | F | – | – | – | – | – | – | 4 | 2 | 0.12 | None | |||
| T1AS81V | F | – | – | – | – | V | – | 32 | 32 | 4 | None | |||
| T1AE85G | F | – | – | – | – | – | G | 32 | 8 | 2 | None | |||
*par, topoisomerase gene; gyr, gyrase gene; CIP, ciprofloxacin; LVX, levofloxacin; MXF, moxifloxacin. Only changes involved in resistance are shown. –, no change. Additional amino acid changes not involved in resistance were parC D78N (1 isolate), parC K137 N (9), parC N91D (2 with mosaic parC genes), parE I460V (17), parE I476F (1), gyrA S114G (2 with mosaic gyrA genes), and gyrA N150H (1 with a mosaic gyrA gene).
†An isolate was considered to have an efflux phenotype for the indicated fluoroquinolone when a >2-fold decrease in its MIC in the presence of reserpine was observed.
‡Indicates that the residue is located in a recombinant gene.
§R6CS80P, R6 derivative carrying parC S80P; T1AS81V, T1-derivative carrying gyrA S81V; T1AE85G, T1-derivative carrying gyrA E85K.