<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>R.K. Cooper</dc:contributor>
  <dc:contributor>E. B. Shotts Jr.</dc:contributor>
  <dc:contributor>P.W. Taylor</dc:contributor>
  <dc:creator>C. E. Starliper</dc:creator>
  <dc:date>1993</dc:date>
  <dc:description>&lt;div class=" metis-abstract"&gt;&lt;div class="article-section__content en main"&gt;&lt;p&gt;Romet®, a potentiated sulfa drug composed of five parts sulfadimethoxine and one part ormetoprim, is used to treat channel catfish&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Ictalurus punctatus&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;infected with&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Edwardsiella ictaluri&lt;/i&gt;, the causal agent of enteric septicemia of catfish (ESC). Recently, several Romet-resistant isolates of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;E. ictaluri&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;were isolated from channel catfish that had died from ESC in Virginia and Mississippi. This antimicrobial resistance was determined to be plasmid-encoded, as shown by agarose gel electrophoresis of plasmid DNA, and by the fact that the plasmid and associated antimicrobial resistance could be transferred to a recipient by single-step conjugation. Size of the R plasmid was approximately 55 kilobase pairs. Plasmids also conferred resistance to tetracycline, oxytetracycline, streptomycin, trimethoprim, and SXT (another potentiated sulfonamide, composed of trimethoprim and sulfamethoxazole). Each Romet-resistant&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;E. ictaluri&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;isolate was mated with a plasmid recipient, the Romet-sensitive&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Escherichia coli&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;isolate 1932. Transconjugates were selected by plating on Mueller-Hinton agar that contained antimicrobials, and the mean transfer frequency was 1.483 × 10&lt;sup&gt;−3&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;transconjugates per donor cell in the mating mixture. Each E. coli transconjugate was then mated with 20 Romet-sensitive isolates of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;E. ictaluri&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;to assess the propensity of these&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;E. ictaluri&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;isolates to accept the R plasmid. The average transfer frequency when&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;E. ictaluri&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;isolates of channel catfish origin (N = 14) were used as recipients was 1.197 × 10&lt;sup&gt;−2&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;transconjugates per donor cell in the mating mixture; mean transfer frequency when&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;E. ictaluri&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;isolates not originating from channel catfish were used was 1.019 × 10&lt;i&gt;-3&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;transconjugates per donor cell, which was significantly less (P = 0.0002).&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1577/1548-8667(1993)005&lt;0001:PMRROE&gt;2.3.CO;2</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Wiley</dc:publisher>
  <dc:title>Plasmid-mediated romet resistance of Edwardsiella ictaluri</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>