Márta Nové1, Annamária Kincses1, József Molnár1, Leonard Amaral1,2, Gabriella Spengler3. 1. Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, Szeged, Hungary. 2. Travel Medicine, Institute of Hygiene and Tropical Medicine, Universidade Nova de Lisboa, Lisbon, Portugal. 3. Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, Szeged, Hungary spengler.gabriella@med.u-szeged.hu.
Abstract
BACKGROUND/AIM: One of the most studied bacterial resistance mechanisms is the resistance related to multidrug efflux pumps. In our study the pump activity of the Escherichia coli K-12 AG100 strain expressing the AcrAB-TolC pump system was investigated at pH 7 and pH 5 in the presence of the efflux pump inhibitor (EPI) promethazine (PMZ). MATERIALS AND METHODS: The EPI activity was assessed by real-time fluorimetry. The influence of PMZ treatment on the relative expression of the pump genes acrA, acrB and their regulators marA, marB, marR, the stress genes soxS, rob, as well as the bacterial growth control genes ftsI, and sdiA were determined by RT-qPCR. RESULTS: The EPI activity of PMZ was more effective at neutral pH. The PMZ treatment induced a significant stress response in the bacterium at acidic pH by the up-regulation of genes. CONCLUSION: The genetic system that regulates the activity of the main efflux pump is pH-dependent. Copyright
BACKGROUND/AIM: One of the most studied bacterial resistance mechanisms is the resistance related to multidrug efflux pumps. In our study the pump activity of the Escherichia coli K-12 AG100 strain expressing the AcrAB-TolC pump system was investigated at pH 7 and pH 5 in the presence of the efflux pump inhibitor (EPI) promethazine (PMZ). MATERIALS AND METHODS: The EPI activity was assessed by real-time fluorimetry. The influence of PMZ treatment on the relative expression of the pump genes acrA, acrB and their regulators marA, marB, marR, the stress genes soxS, rob, as well as the bacterial growth control genes ftsI, and sdiA were determined by RT-qPCR. RESULTS: The EPI activity of PMZ was more effective at neutral pH. The PMZ treatment induced a significant stress response in the bacterium at acidic pH by the up-regulation of genes. CONCLUSION: The genetic system that regulates the activity of the main efflux pump is pH-dependent. Copyright
Authors: Lisa M Maurer; Elizabeth Yohannes; Sandra S Bondurant; Michael Radmacher; Joan L Slonczewski Journal: J Bacteriol Date: 2005-01 Impact factor: 3.490
Authors: Miguel Viveiros; Ana Martins; Laura Paixão; Liliana Rodrigues; Marta Martins; Isabel Couto; Eva Fähnrich; Winfried V Kern; Leonard Amaral Journal: Int J Antimicrob Agents Date: 2008-03-17 Impact factor: 5.283