Table 2.
Resistance genes | No. (%) of isolates |
||
---|---|---|---|
Overexpressiona | Borderline | No overexpression | |
ampC | 96 (68.09) | 12 (8.51) | 33 (23.40) |
mexBb | 17 (12.78) | 20 (15.04) | 96 (72.18) |
IMP-9 | 11 (7.80) | ||
VIM-2 | 9 (6.38) |
aThe mRNA levels of the indicated genes in PAO1 were used as controls. Evaluation criteria are as follows: for ampC overexpression indicates expression at least 10-fold higher than in PAO1, negative indicates expression is lower than 5-fold, and borderline indicates expression is between 5- and 10-fold higher. For mexB, overexpression indicates expression at least 3-fold higher, negative indicates expression is less than 2-fold higher, and borderline indicates expression is between 2- and 3-fold higher. bTranscription of mexB was determined in 133 meropenem-non-susceptible isolates.