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Expression of Pseudomonas aeruginosa multidrug efflux pumps MexA-MexB-OprM and MexC-MexD-OprJ in a multidrug-sensitive Escherichia coli strain.
Antimicrob Agents Chemother. 1998 Jan; 42(1):65-71.AA

Abstract

The mexCD-oprJ and mexAB-oprM operons encode components of two distinct multidrug efflux pumps in Pseudomonas aeruginosa. To assess the contribution of individual components to antibiotic resistance and substrate specificity, these operons and their component genes were cloned and expressed in Escherichia coli. Western immunoblotting confirmed expression of the P. aeruginosa efflux pump components in E. coli strains expressing and deficient in the endogenous multidrug efflux system (AcrAB), although only the delta acrAB strain, KZM120, demonstrated increased resistance to antibiotics in the presence of the P. aeruginosa efflux genes. E. coli KZM120 expressing MexAB-OprM showed increased resistance to quinolones, chloramphenicol, erythromycin, azithromycin, sodium dodecyl sulfate (SDS), crystal violet, novobiocin, and, significantly, several beta-lactams, which is reminiscent of the operation of this pump in P. aeruginosa. This confirmed previous suggestions that MexAB-OprM provides a direct contribution to beta-lactam resistance via the efflux of this group of antibiotics. An increase in antibiotic resistance, however, was not observed when MexAB or OprM alone was expressed in KZM120. Thus, despite the fact that beta-lactams act within the periplasm, OprM alone is insufficient to provide resistance to these agents. E. coli KZM120 expressing MexCD-OprJ also showed increased resistance to quinolones, chloramphenicol, macrolides, SDS, and crystal violet, though not to most beta-lactams or novobiocin, again somewhat reminiscent of the antibiotic resistance profile of MexCD-OprJ-expressing strains of P. aeruginosa. Surprisingly, E. coli KZM120 expressing MexCD alone also showed an increase in resistance to these agents, while an OprJ-expressing KZM120 failed to demonstrate any increase in antibiotic resistance. MexCD-mediated resistance, however, was absent in a tolC mutant of KZM120, indicating that MexCD functions in KZM120 in conjunction with TolC, the previously identified outer membrane component of the AcrAB-TolC efflux system. These data confirm that a tripartite efflux pump is necessary for the efflux of all substrate antibiotics and that the P. aeruginosa multidrug efflux pumps are functional and retain their substrate specificity in E. coli.

Authors+Show Affiliations

Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9449262

Citation

Srikumar, R, et al. "Expression of Pseudomonas Aeruginosa Multidrug Efflux Pumps MexA-MexB-OprM and MexC-MexD-OprJ in a Multidrug-sensitive Escherichia Coli Strain." Antimicrobial Agents and Chemotherapy, vol. 42, no. 1, 1998, pp. 65-71.
Srikumar R, Kon T, Gotoh N, et al. Expression of Pseudomonas aeruginosa multidrug efflux pumps MexA-MexB-OprM and MexC-MexD-OprJ in a multidrug-sensitive Escherichia coli strain. Antimicrob Agents Chemother. 1998;42(1):65-71.
Srikumar, R., Kon, T., Gotoh, N., & Poole, K. (1998). Expression of Pseudomonas aeruginosa multidrug efflux pumps MexA-MexB-OprM and MexC-MexD-OprJ in a multidrug-sensitive Escherichia coli strain. Antimicrobial Agents and Chemotherapy, 42(1), 65-71.
Srikumar R, et al. Expression of Pseudomonas Aeruginosa Multidrug Efflux Pumps MexA-MexB-OprM and MexC-MexD-OprJ in a Multidrug-sensitive Escherichia Coli Strain. Antimicrob Agents Chemother. 1998;42(1):65-71. PubMed PMID: 9449262.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Expression of Pseudomonas aeruginosa multidrug efflux pumps MexA-MexB-OprM and MexC-MexD-OprJ in a multidrug-sensitive Escherichia coli strain. AU - Srikumar,R, AU - Kon,T, AU - Gotoh,N, AU - Poole,K, PY - 1998/2/4/pubmed PY - 1998/2/4/medline PY - 1998/2/4/entrez SP - 65 EP - 71 JF - Antimicrobial agents and chemotherapy JO - Antimicrob. Agents Chemother. VL - 42 IS - 1 N2 - The mexCD-oprJ and mexAB-oprM operons encode components of two distinct multidrug efflux pumps in Pseudomonas aeruginosa. To assess the contribution of individual components to antibiotic resistance and substrate specificity, these operons and their component genes were cloned and expressed in Escherichia coli. Western immunoblotting confirmed expression of the P. aeruginosa efflux pump components in E. coli strains expressing and deficient in the endogenous multidrug efflux system (AcrAB), although only the delta acrAB strain, KZM120, demonstrated increased resistance to antibiotics in the presence of the P. aeruginosa efflux genes. E. coli KZM120 expressing MexAB-OprM showed increased resistance to quinolones, chloramphenicol, erythromycin, azithromycin, sodium dodecyl sulfate (SDS), crystal violet, novobiocin, and, significantly, several beta-lactams, which is reminiscent of the operation of this pump in P. aeruginosa. This confirmed previous suggestions that MexAB-OprM provides a direct contribution to beta-lactam resistance via the efflux of this group of antibiotics. An increase in antibiotic resistance, however, was not observed when MexAB or OprM alone was expressed in KZM120. Thus, despite the fact that beta-lactams act within the periplasm, OprM alone is insufficient to provide resistance to these agents. E. coli KZM120 expressing MexCD-OprJ also showed increased resistance to quinolones, chloramphenicol, macrolides, SDS, and crystal violet, though not to most beta-lactams or novobiocin, again somewhat reminiscent of the antibiotic resistance profile of MexCD-OprJ-expressing strains of P. aeruginosa. Surprisingly, E. coli KZM120 expressing MexCD alone also showed an increase in resistance to these agents, while an OprJ-expressing KZM120 failed to demonstrate any increase in antibiotic resistance. MexCD-mediated resistance, however, was absent in a tolC mutant of KZM120, indicating that MexCD functions in KZM120 in conjunction with TolC, the previously identified outer membrane component of the AcrAB-TolC efflux system. These data confirm that a tripartite efflux pump is necessary for the efflux of all substrate antibiotics and that the P. aeruginosa multidrug efflux pumps are functional and retain their substrate specificity in E. coli. SN - 0066-4804 UR - https://www.unboundmedicine.com/medline/citation/9449262/Expression_of_Pseudomonas_aeruginosa_multidrug_efflux_pumps_MexA_MexB_OprM_and_MexC_MexD_OprJ_in_a_multidrug_sensitive_Escherichia_coli_strain_ L2 - http://aac.asm.org/cgi/pmidlookup?view=long&pmid=9449262 DB - PRIME DP - Unbound Medicine ER -