Plasmid-Mediated Ampicillin Resistance in
            <i>Haemophilus ducreyi</i>

Brunton, James; Maclean, Ian; Ronald, Allan R.; Albritton, William L.

doi:10.1128/aac.15.2.294

Cited by 51 publications

(29 citation statements)

References 28 publications

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“…Plasmid p22209 is structurally identical to pHD747, with the exception of a complete ampicillin transppson within the latter (2). The same relationship exists between plasmids p88557 and pJB1 (2). The ampicillin transposon is not present within pHD147 (11).…”

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confidence: 77%

Characterization of a Haemophilus ducreyi mobilizing plasmid

McNicol¹,

Albritton²,

Ronald³

1986

J Bacteriol

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The OriV site of Haemophilus ducreyi mobilizing plasmid pHD147, determined by replication in Escherichia coli poUA, is located close to the OriT site. The OriT site, located by recombinant plasmid mobilization in recombination-proficient and -deficient cells, and the OriV site map in a region of pHD147 homologous to the beta-lactamase-specifying plasmids of H. ducreyi and Neisseria gonorrhoeae.A mobilizing plasmid described by Deneer et al. (5) mediates intraspecific and intergeneric transfer of Haemophilus ducreyi plasmids. It also mediates transfer of Neisseria gonorrhoeae ampicillin resistance plasmids and shares homology with these and the ampicillin resistance plasmids of H. ducreyi (11). Because this mobilizing plasmid may mediate transfer of antimicrobial resistance plasmids to clinically significant microorganisms, we characterized the structural organization of this plasmid with regard to transfer and maintenance functions. Plasmids and bacterial strains are described in Table 1.Plasmid pHD147 was mapped by restriction endonuclease digest (Fig. 1), and a molecular size estimate of 21.7 megadaltons (MDa) was obtained. This plasmid was previously reported to be 23.5 MDa in size (5). Since pHD147 is maintained by Escherichia coli DNA polymerase I-deficient strain W3110 polA, but pAT153 is not (9), only those pAT153-pHD147 recombinant plasmids containing the origin of replication (OriV) site of pHD147 are maintained in this mutant. Recombinant plasmids, selected in E. coli C600, were created by cloning pHD147 ClaI and XhoII restriction Each recombinant plasmid has a unique HindIII restriction site within the insert and the vector portion. To more accurately locate OriV, pATB1 and pATB5 were digested with Hindlll, the larger restriction fragment recovered by preparative gel electrophoresis (13), and then recircularized with T4 ligase. The newly created plasmids pATBlHind and pATB5Hind (Fig. 2B) were used to transform E. coli W3110 polA. Since pATB5Hind only is maintained, the OriV site of pHD147 is located within the 1.3-MDa XhoII-HindIII restriction fragment ( Fig. 1 and 2). Results are summarized in

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mentioning

confidence: 77%

Characterization of a Haemophilus ducreyi mobilizing plasmid

McNicol¹,

Albritton²,

Ronald³

1986

J Bacteriol

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“…All but one strain contained plasmids similar in size to one of three previously described nonconjugative plasmids of molecular mass 4.9, 5.7, and 7.0 megadaltons (Mdal) (3,6,7). These plasmids are known not to carry the tetracycline resistance determinant.…”

Section: Methodsmentioning

confidence: 99%

“…Strains were screened for the presence of plasmids as described by Meyers et al (19) and previously reported (3,6). Plasmid DNA for restriction digestion was prepared by a modification (8) Fig.…”

Section: Methodsmentioning

confidence: 99%

“…DISCUSSION Plasmid-mediated antibiotic resistance in H. ducreyi has been previously described for ampicillin (5)(6)(7)23) (10,21). Plasmids mediating ampicillin resistance belong to a related group of nonconjugative plasmids described in Neisseria gonorrhoeae and other Haemophilus species (7,17 (8), plasmids conferring multiple resistance were described (12,18 …”

Section: -mentioning

confidence: 99%

“…Since tetracycline resistance has been shown previously to be plasmid mediated in other species of Haemophilus (14), and since plasmid-mediated resistance to ampicillin (5)(6)(7) and sulfonamides (3) has been previously demonstrated in H. ducreyi, we looked for plasmid-mediated resistance to tetracyclines in this species.…”

mentioning

confidence: 99%

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Plasmid-mediated tetracycline resistance in Haemophilus ducreyi

Albritton¹,

Maclean²,

Slaney³

et al. 1984

Antimicrob Agents Chemother

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Clinical isolates of Haemophilus ducreyi were shown to be resistant to tetracycline. Resistance was associated in some strains with a 30-megadalton plasmid capable of transferring resistance in conjugative matings with other strains of H. ducreyi and other species of Haemophilus. Restriction endonuclease digestion patterns suggest a relationship between H. ducreyi plasmids and other tetracycline resistance plasmids in Haemophilus. The presence of plasmid-mediated resistance to the tetracyclines limits the use of these agents for the treatment of chancroid.Tetracyclines have been reported as effective therapy for chancroid (4,24). Recent studies, however, have reported clinical resistance and in vitro resistance of the causative organism, Haemophilus ducreyi, to the tetracyclines (10,15,16). In our laboratory, in vitro studies with a large collection of strains have shown over 90% of the isolates from selected geographic areas to be resistant to tetracyclines.Since tetracycline resistance has been shown previously to be plasmid mediated in other species of Haemophilus (14), and since plasmid-mediated resistance to ampicillin (5-7) and sulfonamides (3) has been previously demonstrated in H. ducreyi, we looked for plasmid-mediated resistance to tetracyclines in this species.We report here the demonstration and preliminary characterization of a conjugative plasmid encoding tetracycline resistance in clinical isolates of H. ducreyi. MATERIALS AND METHODSBacterial strains and plasmids. Bacterial strains and plasmids named in this study are listed in Table 1. The remainder of the strains were clinical isolates of H. ducreyi.Media. Strains of H. ducreyi were routinely grown on GC agar base (GIBCO Diagnostics, Madison, Wis.) supplemented with 1% hemoglobin and 1% CVA enrichment (GIBCO).MICs were determined by agar dilution as described previously (11).Plasmid DNA. Strains were screened for the presence of plasmids as described by Meyers et al. (19) and previously reported (3, 6). Plasmid DNA for restriction digestion was prepared by a modification (8) nisms from 4 ml of these suspensions were filtered onto 0.45-,um polycarbonate filters. After overnight incubation on the surface of a chocolate agar plate, the organisms were resuspended and spread over the surface of chocolate agar containing tetracycline (4 ,ug/ml) and streptomycin (1,000 ,ug/ml). The clones isolated were screened for plasmid DNA, and their antibiotic resistance was confirmed by disk diffusion testing. RESULTSThe distribution of MICs for 35 strains of H. ducreyi is shown in Fig. 1. Resistant strains were defined as those having an MIC 2 4 ,ug/ml. Tetracycline-resistant strains were found in every geographical area surveyed, with the percentage of resistant strains varying from 16 to 100 (Table 2).Forty-one tetracycline-resistant strains were screened for the presence of plasmids. All but one strain contained plasmids similar in size to one of three previously described nonconjugative plasmids of molecular mass 4.9, 5.7, and 7.0 megadaltons (Mdal) (3, ...

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Clinical Efficacy of Antimicrobial Therapy in Haemophilus ducreyi Infections

Boyd¹

1989

Arch Dermatol

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Ulcerative genital disease in the United States is commonly due to herpes simplex or syphilis. Until recently, chancroid, an infection caused by the gram-negative streptobacillus Haemophilus ducreyi, was infrequently diagnosed. Continuing immigration, however, has reintroduced the disease into this country, and urban outbreaks have been associated with contact with infected prostitutes. Extensive resistance has made previous antimicrobial agents ineffective. Evaluations of multiple antibiotics and varied dosing schedules have been undertaken in an effort to circumvent this resistance. Clinicians treating patients with genital ulcerations must be aware of this disease and its geographically variable antibiotic sensitivities. Recent evidence demonstrating an association between seropositivity for the human immunodeficiency virus and ulcerative genital disease places additional importance on the timely diagnosis and appropriate treatment of chancroidal ulcers.

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Plasmid-Mediated Ampicillin Resistance in Haemophilus ducreyi

Cited by 51 publications

References 28 publications

Characterization of a Haemophilus ducreyi mobilizing plasmid

Characterization of a Haemophilus ducreyi mobilizing plasmid

Plasmid-mediated tetracycline resistance in Haemophilus ducreyi

Clinical Efficacy of Antimicrobial Therapy in Haemophilus ducreyi Infections

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