Regulatory relationships among aldB, ampH, and acoR and their impact on β-lactam susceptibility in Phytobacter diazotrophicus

In <i>P. diazotrophicus</i>, <i>aldB</i> and <i>acoR</i> reduced some β-lactam resistance by facilitating <i>ampH</i> and <i>aldB</i> expression, respectively. This is the first report that links <i>acoR</i> to β-lactam antibiotics and demonstrates that AcoR positively regulates <i>aldB</i>. Under ceftazidime stress, <i>P. diazotrophicus</i> reduced <i>aldB</i> expression to increase its tolerance to the antibiotic. The discovery of the mechanism by which AcoR regulates <i>aldB</i> expression provides preliminary evidence for subsequent research on drug resistance mechanisms.