TABLE 2.
In vitro antimicrobial activity of eight oral agents against M. pneumoniae strains (n = 380)
| Antimicrobial agent and MLr class | MIC (μg/ml)a
|
||
|---|---|---|---|
| 50% | 90% | Range | |
| Erythromycin | |||
| Susceptible | 0.0078 | 0.0156 | 0.00195-0.0313 |
| Resistant | |||
| A2063G | 64 | >64 | 32->64 |
| A2064G | >64 | >64 | 64->64 |
| Clarithromycin | |||
| Susceptible | 0.0039 | 0.0078 | 0.00049-0.0313 |
| Resistant | |||
| A2063G | 64 | >64 | 32->64 |
| A2064G | 64 | 64 | 16->64 |
| Azithromycin | |||
| Susceptible | 0.00049 | 0.00098 | 0.00024-0.00195 |
| Resistant | |||
| A2063G | 32 | 64 | 16->64 |
| A2064G | 32 | 64 | 16-64 |
| Telithromycin | |||
| Susceptible | 0.00098 | 0.00195 | 0.00024-0.0039 |
| Resistant | |||
| A2063G | 32 | 64 | 16->64 |
| A2064G | 4 | 16 | 1-16 |
| Josamycin | |||
| Susceptible | 0.0313 | 0.0625 | 0.0156-0.0625 |
| Resistant | |||
| A2063G | 8 | 16 | 0.0625-64 |
| A2064G | 64 | >64 | 64->64 |
| Rokitamycin | |||
| Susceptible | 0.0156 | 0.0156 | 0.0039-0.0313 |
| Resistant | |||
| A2063G | 0.125 | 0.25 | 0.0156-16 |
| A2064G | 16 | 16 | 8-16 |
| Minocycline | |||
| Susceptible | 0.5 | 1 | 0.0313-2 |
| Resistant | |||
| A2063G | 0.5 | 1 | 0.0625-1 |
| A2064G | 0.5 | 1 | 0.0313-1 |
| Levofloxacin | |||
| Susceptible | 0.5 | 1 | 0.125-1 |
| Resistant | |||
| A2063G | 1 | 1 | 0.5-1 |
| A2064G | 1 | 1 | 0.5-1 |
a
MICs were determined by microdilution methods using PPLO broth. Samples (10 μl) from these cultures estimated to contain 105 CFU/ml were inoculated into 96-well microplates filled with 90 μl of PPLO broth containing serially diluted antibiotics. These were incubated aerobically from 10 to 14 days at 37°C until a color change was confirmed in an antibiotic-free growth control. The MIC of each agent was defined as the lowest concentration of each antibiotic preventing the color change.