Dataset Information

Contribution of the multidrug efflux transporter CmeABC to antibiotic resistance in different Campylobacter species.

ABSTRACT: CmeABC, a multidrug efflux system in Campylobacter jejuni, plays an important role in the resistance to different antimicrobials and toxic compounds. Although this efflux system has been well characterized in C. jejuni and to a less extent in C. coli, it is unknown if CmeABC homologs are functional in other Campylobacter spp. In this study, the cmeABC homologs were identified and functionally characterized in five Campylobacter species including C. jejuni, C. coli, C. lari, C. upsaliensis, and C. fetus. Our results indicated that cmeABC is present in all five Campylobacter spp. and the genomic organization of this efflux operon is similar among the Campylobacter spp. Insertional mutagenesis of cmeB increased the susceptibilities of all the five Campylobacter spp. to structurally diverse antimicrobials. Together, these results indicated that the CmeABC efflux system is conserved at both the genomic and functional levels in all five Campylobacter spp. examined in this study, further highlighting the significant role of CmeABC in Campylobacter pathobiology.

SUBMITTER: Guo B

PROVIDER: S-EPMC3145173 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature

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Contribution of the multidrug efflux transporter CmeABC to antibiotic resistance in different Campylobacter species.

Guo Baoqing B Lin Jun J Reynolds Donald L DL Zhang Qijing Q

Foodborne pathogens and disease 20100101 1

CmeABC, a multidrug efflux system in Campylobacter jejuni, plays an important role in the resistance to different antimicrobials and toxic compounds. Although this efflux system has been well characterized in C. jejuni and to a less extent in C. coli, it is unknown if CmeABC homologs are functional in other Campylobacter spp. In this study, the cmeABC homologs were identified and functionally characterized in five Campylobacter species including C. jejuni, C. coli, C. lari, C. upsaliensis, and C ...[more]

PMID: 19785541

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Project description:Campylobacter jejuni is a foodborne pathogen that is recognized as the leading cause of human bacterial gastroenteritis. The widespread use of antibiotics in medicine and in animal husbandry has led to an increased incidence of antibiotic resistance in Campylobacter In addition to a role in multidrug resistance (MDR), the Campylobacter CmeABC resistance-nodulation-division (RND)-type efflux pump may be involved in virulence. As a vehicle for pathogenic microorganisms, the protozoan Acanthamoeba is a good model for investigations of bacterial survival in the environment and the molecular mechanisms of pathogenicity. The interaction between C. jejuni 81-176 and Acanthamoeba polyphaga was investigated in this study by using a modified gentamicin protection assay. In addition, a possible role for the CmeABC MDR pump in this interaction was explored. Here we report that this MDR pump is beneficial for the intracellular survival and multiplication of C. jejuni in A. polyphaga but is dispensable for biofilm formation and motility.IMPORTANCE The endosymbiotic relationship between amoebae and microbial pathogens may contribute to persistence and spreading of the latter in the environment, which has significant implications for human health. In this study, we found that Campylobacter jejuni was able to survive and to multiply inside Acanthamoeba polyphaga; since these microorganisms can coexist in the same environment (e.g., on poultry farms), the latter may increase the risk of infection with Campylobacter Our data suggest that, in addition to its role in antibiotic resistance, the CmeABC MDR efflux pump plays a role in bacterial survival within amoebae. Furthermore, we demonstrated synergistic effects of the CmeABC MDR efflux pump and TetO on bacterial resistance to tetracycline. Due to its role in both the antibiotic resistance and the virulence of C. jejuni, the CmeABC MDR efflux pump could be considered a good target for the development of antibacterial drugs against this pathogen.

Project description:Clinical strains of Stenotrophomonas maltophilia are often highly resistant to multiple antibiotics, although the mechanisms of resistance are generally poorly understood. Multidrug resistant (MDR) strains were readily selected by plating a sensitive reference strain of the organism individually onto a variety of antibiotics, including tetracycline, chloramphenicol, ciprofloxacin, and norfloxacin. Tetracycline-selected MDR strains typically showed cross-resistance to erythromycin and fluoroquinolones and, in some instances, aminoglycosides. MDR mutants selected with the other agents generally displayed resistance to chloramphenicol and fluoroquinolones only, although two MDR strains (e.g., K1385) were also resistant to erythromycin and hypersusceptible to aminoglycosides. Many of the MDR strains expressed either moderate or high levels of a novel outer membrane protein (OMP) of ca. 50 kDa molecular mass, a phenotype typical of MDR strains of Pseudomonas aeruginosa hyperexpressing drug efflux systems. Indeed, the 50-kDa OMP of these S. maltophilia MDR strains reacted with antibody to OprM, the outer membrane component of the MexAB-OprM MDR efflux system of P. aeruginosa. Similarly, a ca. 110-kDa cytoplasmic membrane protein of these MDR strains also reacted with antibody to the MexB component of the P. aeruginosa pump. The outer and cytoplasmic membranes of several clinical S. maltophilia strains also reacted with the anti-OprM and anti-MexB antibodies. N-terminal amino acid sequencing of a cyanogen bromide-generated peptide of the 50-kDa OMP of MDR strain K1385, dubbed SmeM (Stenotrophomonas multidrug efflux), revealed it to be very similar to a number of outer membrane multidrug efflux components of P. aeruginosa and Pseudomonas putida. Deletion of the L1 and L2 beta-lactamase genes confirmed that these enzymes were responsible for the bulk of the beta-lactam resistance of K1385 and its parent. Still, overexpression of the MDR efflux mechanism in an L1- and L2-deficient derivative of K1385 did yield a modest increase in resistance to a few beta-lactams. These data are consistent with the MDR efflux mechanism(s) playing a role in the multidrug resistance of S. maltophilia.

Dataset Information

Contribution of the multidrug efflux transporter CmeABC to antibiotic resistance in different Campylobacter species.

Publications

Contribution of the multidrug efflux transporter CmeABC to antibiotic resistance in different Campylobacter species.

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