The overexpression of SdiA and SoxS is associated with the development of multiple antibiotic resistance induced by diazepam and haloperidol in Escherichia coli AG100

Abstract number: O208

Tavío M.M., Aquili V.D., Vila J., Poveda J.B.

Objectives: The previously described multidrug antibiotic resistance (MAR) phenotype, which is induced in Escherichia coli AG100 by diazepam and haloperidol (drugs used in surgery) is comparable to MAR phenotype resulting from marAB operon activation by salicylate (OmpF loss and enhanced active efflux). Nevertheless, MAR phenotype can also result from the overexpression of other transcriptional regulators such as SoxS. This work studied some transcriptional activators that could be involved in the induction of MAR phenotype by diazepam or haloperidol in the susceptible E. coli AG100 strain.

Methods: The effect of several subinhibitory concentrations of diazepam and haloperidol in the AG100 strain was evaluated on outer membrane protein (OMP) expression, cyclohexane tolerance and the expression of the marA, soxS, rob and sdiA genes. OMP expression was analysed by SDS-PAGE. Expression of the marA, soxS, rob and sdiA genes was studied by reverse transcription of total RNA and PCR of cDNA (RT-PCR), using gapA gene as internal control of expression. PCR products were separated in SDS-PAGE and silver stained, quantifying the levels of gene expression by using ImageQuant TL. AG100 (induced or non-induced with 5 mM salicylate or 0.2 mM paraquat) was the control strain.

Results: MAR phenotype, which was induced by growing concentrations of diazepam or haloperidol, was accompanied by a significant increased expression of sdiA and soxS genes, coinciding with previous results on MAR and increased active efflux induced by subinhibitory concentrations of any of both drugs. A large up-regulation of 8.9-fold for sdiA gene and 12.8-fold for soxS gene was induced by 0.05–0.1 mM haloperidol. The induced decreased expression of OmpF, increased cyclohexane tolerance as well as increased expression of sdiA and soxS genes occurred in a reversible and concentration-dependent manner. AG100 induced by diazepam or haloperidol did not show a significant increment in the expression level of MarA or Rob.


iSdiA, a homologous to the LuxR family of quorum-sensing transcription factors, as well as SoxS were involved in MAR phenotype induced by diazepam or haloperidol.

iiThe MAR phenotype, increased cyclohexane tolerance, and the up-regulation of sdiA and soxS genes were always induced by any of the two studied drugs in a reversible and concentration-dependent manner.

iiiThe decreased expression of OmpF induced by diazepam or haloperidol could be related to SoxS overexpression.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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