Active efflux of antimicrobial agents in wild-type strains of enterococci

Lynch, C; Courvalin, Patrice; Nikaido, Hiroshi

doi:10.1128/aac.41.4.869

Cited by 46 publications

(18 citation statements)

References 17 publications

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“…While the association between CR-VRE and quinolone use is more difficult to explain, it has been shown that exposure to quinolones may result in upregulation of efflux mechanisms that also confer resistance to chloramphenicol [16]. The identification of efflux pumps in enterococci that expel quinolones, chloramphenicol, and tetracycline [17], may help to explain the higher levels of tetracycline resistance noted in our CR-VRE isolates.…”

Section: Discussionmentioning

confidence: 85%

Emergence of resistance to chloramphenicol among vancomycin-resistant enterococcal (VRE) bloodstream isolates

Lautenbach

Gould

Larosa

et al. 2004

International Journal of Antimicrobial Agents

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Section: Discussionmentioning

confidence: 85%

Emergence of resistance to chloramphenicol among vancomycin-resistant enterococcal (VRE) bloodstream isolates

Lautenbach

Gould

Larosa

et al. 2004

International Journal of Antimicrobial Agents

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“…3 thus seems to block not only the NorA pump but also the additional MDR pumps14,15 in S. aureus . Furthermore 3 had excellent antibacterial activity (MIC 3.4 μM, Table 1) against E. faecalis which is known for its high levels of “intrinsic antibiotic resistance”16,17 and was resistant to 1 with an MIC of 650–1300 μM.…”

Section: Resultsmentioning

confidence: 99%

Antibacterial activity of berberine-NorA pump inhibitor hybrids with a methylene ether linking group

Samosorn

Tanwirat

Muhamad

et al. 2009

Bioorganic & Medicinal Chemistry

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Conjugation of the NorA substrate berberine and the NorA inhibitor 5-nitro-2-phenyl-1H-indole via a methylene ether linking group gave the 13-substituted berberine-NorA inhibitor hybrid, 3. A series of simpler arylmethyl ether hybrid structures were also synthesized. The hybrid 3 showed excellent antibacterial activity (MIC Staphylococcus aureus, 1.7 μM), which was over 382-fold more active than the parent antibacterial berberine, against this bacterium. This compound was also shown to block the NorA efflux pump in S. aureus.

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“…There is some homology ( Table 3) with proteins involved in cobalt transport [42^45], which in B. subtilis has been linked to tetracycline transport [46]. E. faecium possesses endogenous e¥ux pumps that excrete tetracycline [47]. Cobalt has been shown to activate an aminopeptidase in Streptococcus sanguis and Saccharomyces cerevisiae [48].…”

Section: Discussionmentioning

confidence: 99%

“…[20,21,23]. In E. faecium systems for enterocin A excretion [49] and antibiotic resistance [40,47] have been described. In E. faecalis an ABC transporter system has been implicated in polysaccharide biosynthesis [50].…”

Section: Discussionmentioning

confidence: 99%

Identification of ABC transporters in vancomycin-resistant Enterococcus faecium as potential targets for antibody therapy

Burnie¹

2002

FEMS Immunology and Medical Microbiology

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The occurrence of an outbreak of septicaemias due to vancomycin-resistant Enterococcus faecium (VRE), in Manchester, UK, provided an opportunity to examine the antibody responses in patients infected by the same strain. Immunoblotting sera from 24 cases, six of whom died, showed an immunodominant cluster of antigens at 34, 54 and 97 kDa, with a statistically significant correlate between survival and immunoglobulin G to the 34 and 97 kDa bands (P<0.05). Screening a genomic expression library of VRE with seropositive serum and peritoneal dialysate from a survivor gave a recombinant clone with two contiguous open reading frames, the derived amino acid sequences of which both showed sequence homologue with ABC transporters, with a Walker A and Walker B motif and the signature sequence LSGGQ. The first open reading frame (putative VRE ABC1) showed 57% homologue with YbxA from Bacillus subtilis. A partial sequence (putative VRE ABC2) was also obtained, in the same recombinant clone, of a second ABC transporter with 72% homologue with ybaE from B. subtilis. Affinity selection with the seropositive serum and peritoneal dialysate used to screen the library showed that the eluted antibody bound to the 97, 54, 34 and 30 kDa bands. Direct amino acid sequencing identified this as a possible ABC transporter. Rabbit antiserum against peptides representing Walker A and an area adjacent to the Walker B site cross-reacted with bands at 34, 54, 97, 110 kDa and at 30, 34 and 54 kDa respectively. This therefore appeared to be an immunodominant complex of ABC transporters of which the smallest was the 30 kDa antigen. Epitope mapping of this antigen with seropositive patients' sera delineated three linear epitopes (KVGIV, FGPKNF and RVAI). The Walker A site represented by peptide 1 (GHNGSGKSTLAKTIN), epitope RVAI represented by peptides 2 (MRRVAIAGVLAMPRE) and 3 (ELSGGQMRRVAIAGV), epitope KVGIV represented by peptide 4 (LKPIRKKVGIVFQFP), and recombinant VRE ABC1 and VRE ABC2 expressed in Escherichia coli pBAD were then used to isolate human genetically recombinant antibodies from a phage antibody display library. An assessment of the protective potential of these antibodies was carried out in a mouse model of the infection. This study suggests that an ABC transporter homologue could be a target for antibody therapy against VRE infections.

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Active efflux of antimicrobial agents in wild-type strains of enterococci

Cited by 46 publications

References 17 publications

Emergence of resistance to chloramphenicol among vancomycin-resistant enterococcal (VRE) bloodstream isolates

Emergence of resistance to chloramphenicol among vancomycin-resistant enterococcal (VRE) bloodstream isolates

Antibacterial activity of berberine-NorA pump inhibitor hybrids with a methylene ether linking group

Identification of ABC transporters in vancomycin-resistant Enterococcus faecium as potential targets for antibody therapy

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