TABLE 2.
Organic solvent tolerance of P. aeruginosa on agar plates
| Strain | Relevant efflux phenotypeb | Growth ona:
|
||
|---|---|---|---|---|
| n-Hexane | p-Xylene | Toluene | ||
| PAO1 | MexAB-OprM+ | + (S) | + (S) | − |
| K1119 | MexAB-OprM− | − | − | − |
| OCR1 | MexAB-OprM++c | + (C) | + (C) | − |
| ML5087 | MexAB-OprM+ | + (S) | + (S) | − |
| K1110 | MexAB+ OprM− | − | − | − |
| K1112d | MexAB-OprM++ | + (C) | + (C) | − |
| K1131 | MexAB-OprM− MexCD-OprJ+ | − | − | − |
| K1117 | MexAB-OprM− MexEF-OprN+ | − | − | − |
| PAO6609 | MexAB-OprM+ | + | + | − |
| K1032 | MexAB-OprM− | − | − | − |
Bacteria (5 μl) were spotted onto LB agar, overlaid with organic solvent, and incubated overnight at 30°C as outlined in the text. +, growth; −, no growth. In parentheses are the results of EOP experiments in which 100-μl cell cultures were plated on the surfaces of LB agar plates, overlaid with organic solvent, and likewise incubated overnight. C, confluent growth; S, single-colony growth. The log Pow values of the solvents were as follows: n-hexane, 3.9; p-xylene, 3.1; toluene, 2.8.
The status of those efflux systems (components) that are known to be expressed and, thus, potentially contribute to the organic solvent tolerance of the indicated strains is highlighted.
High-level expression of MexAB-OprM.
This strain yielded scattered colonies after 72 h of incubation in the presence of toluene.