Format:
1 Online-Ressource
Content:
Campylobacter is a major foodborne pathogen causing human enteric infections. Antibiotic treatments are needed for prolonged and severe cases of campylobacteriosis, but Campylobacter is increasingly resistant to antimicrobials, which has rendered antimicrobial therapy less effective. Multiple mechanisms contribute to antibiotic resistance in Campylobacter, but antibiotic efflux mediated by membrane transporters is considered a significant player in conferring intrinsic and acquired resistance to a broad spectrum of antimicrobials. The recently published genomic sequence revealed the presence of multiple genes encoding efflux transporters in C. jejuni, and work conducted in our laboratory identified that CmeABC, a RND (resistance nodulation and cell division) type efflux pump, serves as a major efflux pump in C. jejuni, contributing to antibiotic resistance, bile resistance, and in vivo colonization of the chicken intestinal tract. Work from our laboratory also found that that CmeABC is controlled by a transcriptional regulator named CmeR and this regulator appears to modulate the expression of multiple membrane transporters in C. jejuni. Despite these recent advances, it is unclear if CmeABC is present and functional in other Campylobacter spp; the functions and regulatory mechanisms of other efflux transporters are not known; and the role of the CmeR-regulated membrane transporters in Campylobacter pathophysiology remains to be determined. In this project, we conducted a series of studies to address these questions using both in vitro and in vivo approaches. In the first study, we successfully identified CmeABC in C. coli, C. upsaliensis, C. lari , and C. fetus and found that the genomic organizations and predicted structures CmeABC are conserved in the Campylobacter spp. Insertional mutagenesis of CmeABC showed that this efflux pump is functional in Campylobacter spp. and contributes to their intrinsic resistance to a range of structurally diverse antimicrobials a
Note:
Dissertation Digital Repository @ Iowa State University 2007
Language:
English
Keywords:
Hochschulschrift
URL:
http://www.worldcat.org/oclc/910205365
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