Expression of the Fluoroquinolones Efflux Pump Genes acrA and mdfA in Urinary Escherichia coli Isolates


Share / Export Citation / Email / Print / Text size:

Polish Journal of Microbiology

Polish Society of Microbiologists

Subject: Microbiology


ISSN: 1733-1331
eISSN: 2544-4646





Volume / Issue / page

Related articles

VOLUME 66 , ISSUE 1 (March 2017) > List of articles

Expression of the Fluoroquinolones Efflux Pump Genes acrA and mdfA in Urinary Escherichia coli Isolates

Sarah M. Abdelhamid / Rania R. Abozahra *

Keywords : Escherichia coli, acrA and mdfA genes, efflux pump, levofloxacin, overexpression

Citation Information : Polish Journal of Microbiology. Volume 66, Issue 1, Pages 25-30, DOI:

License : (CC BY-NC-ND 4.0)

Received Date : 19-February-2016 / Accepted: 02-June-2016 / Published Online: 30-March-2017



Escherichia coli is one of the most frequent causes of urinary tract infections. Efflux system overexpression is reported to contribute to E. coli resistance to several antibiotics. Our aim in this study was to investigate the relation between antibiotic resistance and the expres­sion of the efflux pump genes acrA and mdfA in E. coli by real-time reverse transcription-PCR. We tested the in vitro susceptibilities to 12 antibiotics in 28 clinical isolates of E. coli obtained from urine samples. We also determined the minimum inhibitory concentrations of levofloxacin to these samples. We then revealed significant correlations between the overexpression of both mdfA and acrA and MICs of levofloxacin. In conclusion, we demonstrated that the increased expression of efflux pump genes such as mdfA and acrA can lead to levofloxacin resistance in E. coli. These findings contribute to further understanding of the molecular mechanisms of efflux pump systems and how they contribute to antibiotic resistance.

Content not available PDF Share



Acar J.F. and F.W. Goldstein. 1997. Trends in bacterial resistance to fluoroquinolones. Clin. Infect. Dis. 24(Suppl 1): S67–S73.


Bohnert J.A., S. Schuster, E. Fahnrich, R. Trittler, and W.V. Kern. 2007. Altered spectrum of multidrug resistance associated witha single point mutation in the Escherichia coli RND type MDR efflux pump YhiV (MdtF). J. Antimicrob. Chemother. 59: 1216–1222.


Clinical and Laboratory Standards Institute (CLSI). 2015. Performance standards for antimicrobial disk and dilution susceptibility tests for bacteria isolated from animals, 3rd ed. CLSI document M31-A3. Clinical and Laboratory Standards.


Drlica K., X. Zhao, M. Malik and T.K.R. Salz. 2012. Fluoroquinolone resistance: mechanisms, restrictive dosing, and anti-mutant screening strategies for new compounds, pp. 485–514. In: Dougherty T.J. and M.J. Pucci (eds). Antibiotic Discovery and Development. 1st ed. Springer, US.


Edgar R. and E. Bibi. 1997. MdfA, an Escherichia coli multidrug resistance protein with an extraordinarily broad spectrum of drug recognition. J. Bacteriol. 179: 2274–2280.


Fleige S. and M.W. Pfaffl. 2006. RNA integrity and the effect onthe real-time qRT-PCR performance. Mol. Aspects Med. 27: 126–139.


Han J.H., I. Nachamkin, P. Tolomeo, X. Mao, W.B. Bilker and E. Lautenbach. 2012. Risk factors for efflux pump overexpression in fluoroquinolone-resistant Escherichia coli. J. Infect. Dis. 206: 1597–1603.


Jandu N., N.K.L. Ho, K.A. Donato, M.A. Karmali, M. Mascarenhas, S.P. Duffy, C. Tailor and P.M. Sherman. 2009. Enterohemorrhagic Escherichia coli O157:H7 gene expression profiling in response to growth in the presence of host epithelia. PLoS One 4: e4889.


Jang W.H., D.H. Yoo and S.W. Park. 2011. Prevalence of and risk factors for levofloxacin-resistant E. coli isolated from outpatients with urinary tract infection. Korean J. Urol. 52: 554–559.


Johnson L., A. Sabel, W.J. Burman, R.M. Everhart, M. Rome,T.D. MacKenzie, J. Rozwadowski, P.S. Mehler and C.S. Price. 2008. Emergence of fluoroquinolone resistance in outpatient urinary Escherichia coli isolates. Am. J. Med. 121: 876–884.


Kallen A.J., H.G. Welch and B.E. Sirovich. 2006. Current antibiotic therapy for isolated urinary tract infections in women. Arch. Intern. Med. 166: 635–639.


Kariuki S., G. Revathi, J. Corkill, J. Kiiru, J. Mwituria, N. Mirza and C.A. Hart. 2007. Escherichia coli from community-acquired urinary tract infections resistant to fluoroquinolones and extended-spectrum beta-lactams. J. Infect. Dev. Ctries. 1: 257–262.


Keeney D., A. Ruzin, F. McAleese, E. Murphy and P.A. Bradford. 2008. MarA-mediated overexpression of the AcrAB efflux pump results in decreased susceptibility to tigecycline in Escherichia coli. J. Antimicrob. Chemother. 61: 46–53


Kronvall G. 2010. Antimicrobial resistance 1979–2009 at Karolinska hospital, Sweden: normalized resistance interpretation during a 30-year follow-up on Staphylococcus aureus and Escherichia coli resistance development. APMIS 118: 621–639.


Lomovskaya O. and K.A. Bostian. 2006. Practical applications and feasibility of efflux pump inhibitors in the clinic – a vision for applied use. Biochem. Pharmacol. 71: 910–918.


Magiorakos A.P., A. Srinivasan, R.B. Carey, Y. Carmeli, M.E. Falagas, C.G. Giske, S. Harbarth, J.F. Hindler, G. Kahlmeter andothers. 2012. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clin. Microbiol. Infect. 18: 268–281.


Mohamed Al-Agamy M.H., M.S. El-Din Ashour and I. Wiegand. 2006. First description of CTX-M beta-lactamase-producing clinical Escherichia coli isolates from Egypt. Int. J. Antimicrob. Agents 27: 545–548.


Morgan-Linnell S.K., L. Becnel Boyd, D. Steffen and L. Zechiedrich. 2009. Mechanisms accounting for fluoroquinolone resistance in Escherichia coli clinical isolates. Antimicrob. Agents Chemother. 53: 235–241.


Nikaido H. and J.M. Pagès. 2012. Broad-specificity efflux pumps and their role in multidrug resistance of Gram-negative bacteria. FEMS Microbiol. Rev. 36: 340–363.


Oethinger M. and S.B. Levy. 2001. Methods of reducing microbial resistance to drugs. Retrieved from, 2016.02.10.


Oethinger M. and S.B. Levy. 2011. Methods of screening for com-pounds that reduce microbial resistance to fluoroquinolones. Retrie-ved from, 2016.02.10.


Okeke I.N., R. Laxminarayan, Z. a Bhutta, A.G. Duse, P. Jenkins, T.F. O’Brien, A. Pablos-Mendez and K.P. Klugman. 2005. Antimicrobial resistance in developing countries. Part I: Recent trends and current status. Lancet Infect. Dis. 5: 481–493.


Paterson D.L. 2004. “Collateral damage” from cephalosporin or quinolone antibiotic therapy. Clin. Infect. Dis. 38(Suppl 4):S341–S345.


Pfaffl M.W., G.W. Horgan and L. Dempfle. 2002. Relative expression software tool (REST) for group-wise comparison and statistical analysis of relative expression results in real-time PCR. Nucleic Acids Res. 30: e36


Poole K. 2005. Efflux-mediated antimicrobial resistance. J. Antimicrob. Chemother. 56: 20–51


Rahmati S., S. Yang, A.L. Davidson and E.L. Zechiedrich. 2002. Control of the AcrAB multidrug efflux pump by quorum-sensing regulator SdiA. Mol. Microbiol. 43: 677–685.


Schmitz F.J., A.C. Fluit, M. Lückefahr, B. Engler, B. Hofmann,J. Verhoef, H.P. Heinz, U. Hadding and M.E. Jones. 1998. The effect of reserpine, an inhibitor of multidrug efflux pumps, on the in vitro activities of ciprofloxacin, sparfloxacin and moxifloxacin against clinical isolates of Staphylococcus aureus. J. Antimicrob.Chemother. 42: 807–810.


Shaheen H.I., S.B. Khalil, M.R. Rao, R. Abu Elyazeed, T.F. Wierzba, L.F. Peruski Jr., S. Putnam, A. Navarro, B.Z. Morsy and others. 2004. Phenotypic profiles of enterotoxigenic Escherichia coli associated with early childhood diarrhea in rural Egypt. J. Clin. Microbiol. 42: 5588–5595.


Singh R., M.C. Swick, K.R. Ledesma, Z. Yang, M. Hu, L. Zechiedrich and V.H. Tam. 2012. Temporal interplay between efflux pumps and target mutations in development of antibiotic resistance in Escherichia coli. Antimicrob. Agents Chemother. 56: 1680–1685.


Sun J., Z. Deng and A. Yan. 2014. Bacterial multidrug efflux pumps: Mechanisms, physiology and pharmacological exploitations. Biochem. Biophys. Res. Commun. 453: 254–267.


Swick M.C., S.K. Morgan-Linnell, K.M. Carlson and L. Zechiedrich. 2011. Expression of multidrug efflux pump genes acrAB-tolC, mdfA, and norE in Escherichia coli clinical isolates as a function of fluoroquinolone and multidrug resistance. Antimicrob. Agents Chemother. 55: 921–924.


Szabo A., C.M. Perou, M. Karaca, L. Perreard, R. Palais, J.F. Quackenbush and P.S. Bernard. 2004. Statistical modeling for selecting housekeeper genes. Genome Biol. 5: R59.


Taylor S., M. Wakem, G. Dijkman, M. Alsarraj and M. Nguyen. 2010. A practical approach to RT-qPCR-Publishing data that conform to the MIQE guidelines. Methods 50: S1–S5.


Wagenlehner F.M.E., G. Schmiemann, U. Hoyme, R. Fünfstück, E. Hummers-Pradier, M. Kaase, E. Kniehl, I. Selbach, U. Sester and others. 2011. National S3 guideline on uncomplicated urinary tract infection: recommendations for treatment and management of uncomplicated community-acquired bacterial urinary tract infections in adult patients. Urologe. A. 50: 153–169.


Yang S. 2003. Relative contributions of the AcrAB, MdfA and NorE efflux pumps to quinolone resistance in Escherichia coli. J. Antimicrob. Chemother. 51: 545–556.


Yasufuku T., K. Shigemura, T. Shirakawa, M. Matsumoto, Y. Nakano, K. Tanaka, S. Arakawa, S. Kinoshita, M. Kawabata and others. 2011. Correlation of overexpression of efflux pump genes with antibiotic resistance in Escherichia coli strains clinically isolated from urinary tract infection patients. J. Clin. Microbiol. 49: 189–194.


Yoshihara E. and H. Inoko. 2011. Method or agent for inhibiting the function of efflux pump Pseudomonas aeruginosa., 2016.02.10.