TABLE 1.
Isolate characteristics and response to urinary fosfomycin exposuresb
| Strain | Fosfomycin susceptibility |
Growth control (baseline HLR [%]) | Postexposure outcomea (bacterial count [log10 CFU/ml]/MIC [μg/ml]; HLR proportion) |
||||||
|---|---|---|---|---|---|---|---|---|---|
| MIC (μg/ml) | Disk diffusion (mm) | Single dose |
3 doses |
||||||
| Avg Cmax | Low Cmax | High Cmax | Every 72 h | Every 48 h | Every 24 h | ||||
| E. coli | |||||||||
| 41 | ≤0.25 | 33 | − | − | − | − | − | − | − |
| 11 | 0.5 | 36 | − | − | − | − | − | − | − |
| 39 | 0.5 | 32 | − | − | − | − | − | − | − |
| 12620 | 2 | 26 | − | − | − | − | − | − | − |
| 1016 | 16 | 20 | 2E−04 | 9.5/256; HLR +++ | 9.0/>1,024; HLR +++ | 9.0/>1,024; HLR +++ | 9.6/>1,024; HLR +++ | 9.5/>1,024; HLR +++ | 9.6/>1,024; HLR +++ |
| 1231 | 32 | 20 | 2E−04 | 9.5/>1,024; HLR +++ | 9.1/>1,024; HLR +++ | 9.3/>1,024; HLR +++ | 9.5/>1,024; HLR +++ | 9.3/>1,024; HLR +++ | 9.3/>1,024; HLR +++ |
| 4807 | 32 | 29 | − | − | − | − | − | − | − |
| 4757 | 64 | 26 | − | − | − | 6.3/64; no HLR | − | 7.5/64; HLR + | − |
| E. cloacae | |||||||||
| 35166 | 0.5 | 36 | − | − | − | − | − | − | − |
| 94 | 1 | 40 | − | − | − | − | − | − | − |
| 21 | 8 | 22 | 2E−05 | 9.5/>1,024; HLR +++ | 8.4/8; HLR +++ | 9.5/32; HLR ++ | 8.9/16; HLR +++ | 8.6/>1,024; HLR +++ | 6.6/16; no HLR |
| 32 | 32 | 17 | 5E−04 | 9.5/>1,024; HLR +++ | 9.4/>1,024; HLR +++ | 9.9/>1,024; HLR +++ | 9.7/>1,024; HLR +++ | 9.5/>1,024; HLR +++ | 9.4/>1,024; HLR +++ |
| K. pneumoniae | |||||||||
| 34672 | 2 | 23 | 1E−05 | 9.3/>1,024; HLR +++ | 7.3/4; HLR +++ | 9.6/1,024; HLR + | 9.5/>1,024; HLR +++ | 8.8/512; HLR ++ | − |
| 31865 | 2 | 22 | 2E−04 | 9.4/256; HLR ++ | 3.9/2; no HLR | 7.5/32; no HLR | − | 6.8/2; no HLR | 5.9/2; no HLR |
| 55 | 4 | 19 | 1E−04 | 6.9/4; no HLR | 4.6/8; no HLR | 9.6/>1,024; HLR + | 9.4/>1,024; HLR +++ | 9.5/512; HLR +++ | 9.5/512; HLR + |
| 52 | 16 | 21 | 5E−04 | 9.2/>1,024; HLR +++ | 6.8/16; no HLR | 2.8/256; no HLR | 9.6/16; HLR ++ | 5.2/16; no HLR | 9.2/1,024; HLR ++ |
a
Postexposure outcome was determined as no growth or the bacterial count measured at the final time point (72 h after the last administered fosfomycin dose). The fosfomycin MIC was reassessed on the total population regrowth (values presented in boldface type); dark gray shading highlights a >2-log2 rise in the MIC, and light gray shading highlights growth without a significant rise in MIC. The HLR proportion of the total population is presented as greater than 1% (+++), between 0.01 and 1% (++), or less than 0.01% (+). MIC testing of all HLR subpopulations confirmed MICs of ≥1,024 μg/ml after subculturing on TSB.
b
− indicates not detected or no growth.