Survey of plasmids and resistance factors in Campylobacter jejuni and Campylobacter coli

Abstract

A total of 688 isolates of Campylobacter jejuni and Campylobacter coli were screened for the presence of plasmid DNA by agarose gel electrophoresis and were tested for susceptibility to ampicillin, chloramphenicol, erythromycin, streptomycin, and tetracycline. Of the isolates examined, 32% were noted to harbor plasmid DNA, ranging in size from 2.0 to 162 kilobases. Only tetracycline resistance was noted to correlate with the presence of plasmids. Plasmids capable of transferring tetracycline resistance via conjugation ranged in size from 42 to 100 kilobases. The BglII and BcII restriction endonuclease profiles of 31 plasmids examined showed marked diversity in their banding patterns. Although a high degree of DNA-DNA homology was noted among the Campylobacter spp. plasmids, no homology was noted between these plasmids and tetracycline R factors commonly found in the family Enterobacteriaceae.Campylobacter jejuni and Campylobacter coli now have been established as agents of acute diarrheal disease in both animals and humans worldwide (3,5,19). Although there have been many reports describing the epidemiology and clinical aspects of campylobacter infections (for reviews, see references 3 and 4), little has been reported about the extrachromosomal gene pool of the organisms.The first report of plasmids in the genus Campylobacter and their possible association with antibiotic resistance was published by Austen and Trust (1). Of the 29 strains of "related vibrios" they screened for extrachromosomal DNA, 6 harbored plasmids. No attempt was made to determine whether specific antibiotic resistance genes were plasmid encoded.The first plasmid shown to mediate antibiotic resistance in C. jejuni was described by Taylor and associates (21). This 38-megadalton R factor was capable of transferring tetracycline resistance via conjugation to other Campylobacter strains including C. jej'uni and Campylobacter fetus but not to Escherichia coli. A similar replicon was noted by Tenover and associates in isolates of C. jejuni recovered from simians (23).More recent studies by Taylor and co-workers (22) have demonstrated a high degree of homology among six Campylobacter R factors obtained from strains isolated in Canada, Belgium, and the United States, despite differences in their restriction endonuclease profiles. These same R factors shared no DNA homology with tetracycline R plasmids common to the family Enterobacteriaceae.The goals of this study were three: first, to establish the prevalence of plasmids within isolates of C. jejuni and C. coli in King County, Wash.; second, to determine whether these plasmids carried antibiotic resistance genes; and third, to characterize the R factors that were identified.(This study was presented in part at the 23rd Interscience

Plasmid-mediated tetracycline resistance in Campylobacter jejuni: expression in Escherichia coli and identification of homology with streptococcal class M determinant

“…None of the plasmids showed homology to any of the four classes of determinant from Enterobacteriaceae (11). These findings were subsequently confirmed by others (2,13 (4) by replicaplating 300 colonies onto Mueller-Hinton agar (Oxoid Ltd., London, England) with and without tetracycline (8 ,ug/ml).…”

“…No plasmid-free derivatives were isolated spontaneously, but after exposure to 5 ,ug of ethidium bromide per ml, three plasmid-free derivatives were isolated from 1,500 colonies plated. Previous studies had indicated which restriction enzymes were likely to be useful for restriction mapping of C. jejuni plasmids (11,13). Plasmid DNA from pUA466 and its tetracycline-susceptible derivative, pUA649, were digested with AccI, AvaI, AvaII, BclI, HincII, PstI, XhoI, and XbaI (Boehringer Mannheim Canada, Ltd., Dorval, Quebec, or New England Nuclear Corp., Boston, Mass.)…”

Involvement of a Plasmid in Virulence of Campylobacter jejuni 81-176

“…but not to Escherichia coli (53)(54)(55)(56)(57)(58)60). Despite the importance of plasmids to virulence in numerous other pathogens, it is generally believed that plasmids play no role in Campylobacter pathogenicity.…”

Nucleotide sequence analysis of tetracycline resistance gene tetO from Streptococcus mutans DL5

“…2 (27,29) or the three streptococcal tet determinants (28) Two inverted repeats, potentially associated with the termination of transcription, were located downstream from the termination codon of tetOs (Fig. 3).…”

“…tetM was most often nonplasmid-mediated in the strains examined by Burdett et al (3). Tobian is usually plasmid mediated (27,29). Taylor et al (27) and Tenover et al (29) showed that Tcr plasmids from campylobacters do not hybridize to any of the tet determinants described by Levy and co-workers (15,21).…”