TABLE 4.
COMSTAT analysis of z stacks from 24-h-old biofilms of Acinetobacter baumannii ATCC 15151(pGFP-apra) on glass coverslips exposed to antimicrobials at susceptibility breakpoint concentrationsa
| Antimicrobial(s) | Biomass (mm3/mm2) | Maximum thickness (mm) | Mean thickness (mm) | Roughness coefficient |
|---|---|---|---|---|
| No antimicrobial | 17.39 ± 4.50 | 40.52 ± 1.26 | 23.62 ± 5.61 | 0.36 ± 0.19 |
| MEM | 19.90 ± 6.63 | 36.84 ± 1.44b | 26.92 ± 5.13 | 0.25 ± 0.18 |
| IPM | 17.20 ± 9.21 | 35.71 ± 2.42b | 23.07 ± 9.60 | 0.34 ± 0.22 |
| SUL | 16.61 ± 8.20 | 40.89 ± 2.85 | 25.38 ± 6.97 | 0.43 ± 0.24 |
| CST | 17.18 ± 4.70 | 38.47 ± 3.21 | 22.87 ± 4.21 | 0.26 ± 0.12 |
| TGC | 16.90 ± 5.48 | 38.07 ± 3.19 | 22.63 ± 5.99 | 0.39 ± 0.18 |
| MEM + SULc | 8.32 ± 4.84b | 34.92 ± 3.33b | 13.70 ± 6.69b | 0.73 ± 0.28b |
| SUL + TGCd | 12.40 ± 4.50b | 32.55 ± 2.58b | 16.50 ± 3.84b | 0.52 ± 0.19 |
All results are an average of the results from 8 image stacks acquired in 4 separate experiments. Values are mean ± standard deviation. Susceptibility breakpoint concentrations of antimicrobials were: meropenem (MEM), 2 mg/liter; imipenem (IPM), 2 mg/liter; sulbactam (SUL), 4 mg/liter; colistin (CST), 2 mg/liter; and tigecycline (TGC), 2 mg/liter.
P < 0.05 for the group with antimicrobials versus the group without antimicrobials.
The meropenem-plus-sulbactam group differed significantly (P < 0.05) from the sulbactam-only group in all four parameters and from the meropenem-only group in biomass, mean thickness, and roughness coefficient, but not in maximum thickness.
The sulbactam-plus-tigecycline group differed significantly (P < 0.05) from the sulbactam-only group and from the tigecycline-only group in maximum thickness and mean thickness.