TY - JOUR AU - Y Huang AU - M Adamek AU - C Walker AU - M Runge AU - D Steinhagen AB - The aim of this study was to investigate differences in presence and expression of virulence factors between biotype 1 and 2 strains of 82 Yersinia (Y.) ruckeri isolates, collected from North West Germany during the period of 2004–2012, and to analyze the cytotoxicity of these strains to different fish cell lines. The common virulence factor genes, such as yhlA and yhlB encoding for hemolysin YhlA, rucC and rupG encoding for ruckerbactin, yrp1 and yrpDEF for ABC exporter protein system, and two flagellar genes, including flgA for flagellar secretion chaperones and flhA for flagellar secretion apparatus, were found present in both biotype 1 and 2 isolates of Y. ruckeri collected from North West Germany using multiplex PCR. mRNA expression of these genes was compared between the two biotypes of Y. ruckeri. There was no significant diversity (p gt; 0.05) in the expression of these genes between biotype 1 and 2 strains. 27 Y. ruckeri isolates from different typing groups were analysed in cytotoxicity tests to common carp brain (CCB), epithelioma papulosum cyprini (EPC), fathead minnow epithelial (FHM) and rainbow trout gonad-2 (RTG-2) cells, respectively. In vitro cytotoxicity of the isolates to CCB, EPC and FHM was higher than that to RTG-2 (p lt; 0.05). At 15°C the maximum cytotoxicity to FHM and EPC was higher in non-motile strains than in motile stains after an incubation of 24 h (p lt; 0.05), however, after 48 h, there was no significant difference (p gt; 0.05) of cytotoxicity between those two biotypes. Our results suggest that biotype 2 strains from North West Germany are homogenous with biotype 1 strains on the basis of genetic virulence factor genes. At lower temperature non-motile Y. ruckeri isolates were found more active than motile strains, which could explain why in winter non-motile strains were found more often responsible for ERM outbreaks than motile strains. KeywwordsEnteritic red mouth disease, Biotype, cytotoxicity, mRNA expression, Flagellar genes BT - Berliner und Münchener Tierärztliche Wochenschrift C1 - {"oldId":79892,"title":"In vitro cytotoxicity and multiplex PCR detection of virulence factors of Yersinia ruckeri isolated from rainbow trout in North West Germany","topline":"","teaserText":"Untersuchungen zur In-vitro-Zytotoxizit\u00e4t und zum Nachweis von Virulenzfaktoren mittels Multiplex-PCR bei Yersinia ruckeri- Isolaten aus Teichwirtschaften in Nord-Westdeutschland","content":"

Summary<\/span>
The aim of this study was to investigate differences in presence and expression of virulence factors between biotype 1 and 2 strains of 82 Yersinia <\/span>(Y.<\/span>) ruckeri <\/span>isolates, collected from North West Germany during the period of 2004\u20132012, and to analyze the cytotoxicity of these strains to different fish cell lines. The common virulence factor genes, such as yhlA <\/span>and yhlB <\/span>encoding for hemolysin YhlA<\/span>, rucC<\/span> and rupG <\/span>encoding for ruckerbactin, yrp1 <\/span>and yrpDEF <\/span>for ABC exporter protein system, and two flagellar genes, including flgA <\/span>for flagellar secretion chaperones and flhA <\/span>for flagellar secretion apparatus, were found present in both biotype 1 and 2 isolates of Y. ruckeri <\/span>collected from North West Germany using multiplex PCR. mRNA expression of these genes was compared between the two biotypes of Y. ruckeri<\/span>. There was no significant diversity (p gt; 0.05) in the expression of these genes between biotype 1 and 2 strains. 27 Y. ruckeri <\/span>isolates from different typing groups were analysed in cytotoxicity tests to common carp brain (CCB), epithelioma papulosum cyprini (EPC), fathead minnow epithelial (FHM) and rainbow trout gonad-2 (RTG-2) cells, respectively. In vitro cytotoxicity of the isolates to CCB, EPC and FHM was higher than that to RTG-2 (p lt; 0.05). At 15\u00b0C the maximum cytotoxicity to FHM and EPC was higher in non-motile strains than in motile stains after an incubation of 24 h (p lt; 0.05), however, after 48 h, there was no significant difference (p gt; 0.05) of cytotoxicity between those two biotypes. Our results suggest that biotype 2 strains from North West Germany are homogenous with biotype 1 strains on the basis of genetic virulence factor genes. At lower temperature non-motile Y. ruckeri <\/span>isolates were found more active than motile strains, which could explain why in winter non-motile strains were found more often responsible for ERM outbreaks than motile strains. <\/p>

Keywwords<\/span>
Enteritic red mouth disease, Biotype, cytotoxicity, mRNA expression, Flagellar genes <\/p>

Zusammenfassung<\/span>
In der vorliegenden Studie wurden 82 Yersinia <\/span>(Y.<\/span>) ruckeri-<\/span>Isolate, die 2004 bis 2012 von Fischen aus Teichwirtschaften in Nord-Westdeutschland isoliert wurden, auf Vorkommen und Expression von Virulenzfaktoren sowie auf Zytotoxizit\u00e4t gegen\u00fcber unterschiedlichen Fischzellen untersucht. Dabei sollten vor allem Unterschiede zwischen Isolaten aus den Biotypen 1 und 2 analysiert werden. Untersucht wurden Gene f\u00fcr beschriebene Virulenzfaktoren: yhlA <\/span>und yhlB<\/span>, die das H\u00e4molysin YhlA <\/span>codieren, rucC <\/span>und rupG<\/span>, die das Ruckerbactin codieren, yrp1<\/span> und yrpDEF<\/span>, die Elemente des ABC-Protein-Exkretionssystems codieren, sowie zwei Gene, die Gei\u00dfel-assoziierte Proteine codieren: flhA<\/span>, das ein Protein des Gei\u00dfel-assoziierten Sekretionsapparates codiert, sowie flgA<\/span>, das ein Gei\u00dfel-assoziiertes Sekretions-Chaperon codiert. Alle Gene lie\u00dfen sich in allen untersuchten Isolaten aus Nord-Westdeutschland mittels Multiplex-PCR nachweisen. Zudem wurde die mRNA-Expression dieser Gene bei Isolaten aus beiden Biotypen von Y. ruckeri <\/span>verglichen. Alle analysierten Gene waren bei den untersuchten Isolaten nicht unterschiedlich exprimiert. Des Weiteren wurden 27 Y. ruckeri<\/span>-Isolate aus unterschiedlichen Typisierungsgruppen in vitro auf ihre Zytotoxizit\u00e4t auf die Fischzelllinen \u201ecommon carp brain\u201c (CCB), Epithelioma papulosum cyprini (EPC), \u201efathead minnow epithelial cells\u201c (FHM), und \u201erainbow trout gonad-2\u201c (RTG-2) gepr\u00fcft. Die Mehrzahl der Y. ruckeri<\/span>-Isolate wies eine geringe In-vitro-Zytotoxizit\u00e4t auf. Die Zytotoxizit\u00e4t war gegen\u00fcber den CCB-, EPC- und FHM-Zellen h\u00f6her als gegen\u00fcber RTG-2-Zellen (p lt; 0,05). Bei 15 \u00b0C war nach 24 h Inkubation die maximale Zytotoxizit\u00e4t nicht motiler Y. ruckeri<\/span>-Isolate gegen\u00fcber EPC- und FHM-Zellen h\u00f6her als bei motilen Isolaten (p lt; 0,05). Nach 48 h Inkubationszeit war kein Unterschied zwischen Isolaten aus beiden Biotypen erkennbar. Unsere Ergebnisse lassen vermuten, dass bei Y. ruckeri<\/span>-Isolaten in Nord-Westdeutschland das Vorkommen von Virulenzfaktoren in beiden Biotypen einheitlich ist. Bei niedrigen Temperaturen scheinen nicht motile Y. ruckeri<\/span>-Isolate eine h\u00f6here Zytotoxizit\u00e4t aufzuweisen, was erkl\u00e4ren k\u00f6nnte, warum diese im Winter h\u00e4ufiger f\u00fcr Ausbr\u00fcche der Rotmaulseuche verantwortlich waren als motile Isolate. <\/p>

Schl\u00fcsselw\u00f6rter<\/span>
Rotmaulseuche, Biotyp, Zytotoxizit\u00e4t, mRNA-Expression, Gei\u00dfelassoziierte Gene<\/p>","categories":["Tier\u00e4rztliche Wochenschrift","Abostufe BMTW","Fachartikel"],"fromDate":"Jun 27, 2014 9:26:28 PM","oldUrls":["http:\/\/vetline.de\/in-vitro-cytotoxicity-and-multiplex-pcr-detection-of-virulence-factors-of-yersinia-ruckeri-isolated-from-rainbow-trout-in-north-west-germany\/150\/3130\/79892"],"doiLanguage":"englisch","doiProductFormat":"online","doiPublisher":"Schl\u00fctersche Verlagsgesellschaft mbH & Co. KG","doiSerialWorkTitle":"Berliner und M\u00fcnchener Tier\u00e4rztliche Wochenschrift","doiDocumentUri":"http:\/\/www.vetline.de\/in-vitro-cytotoxicity-and-multiplex-pcr-detection-of-virulence-factors-of-yersinia-ruckeri-isolated-from-rainbow-trout-in-north-west-germany\/150\/3130\/79892\/","doiSource":"Berl M\u00fcnch Tier\u00e4rztl Wochenschr 127, 233\u2013242 (2014)","doiissn":"0005-9366","doiNr":"10.2376\/0005-9366-127-233","doiFirstPage":"233","doiLastPage":"242","doiTransmitted":true,"doiAuthor":"Huang Y, Adamek M, Walker C, Runge M, Steinhagen D","pdf":{"path":"http:\/\/data\/BMW_2014_05_06_0233.pdf","title":"BMW_2014_05_06_0233.pdf","description":"In vitro cytotoxicity and multiplex PCR detection of virulence factors of Yersinia ruckeri isolated from rainbow trout in North West Germany "},"authors":[{"firstName":"Y","middleName":"","lastName":"Huang"},{"firstName":"M","middleName":"","lastName":"Adamek"},{"firstName":"C","middleName":"","lastName":"Walker"},{"firstName":"M","middleName":"","lastName":"Runge"},{"firstName":"D","middleName":"","lastName":"Steinhagen"}],"contentOptimised":"

Summary<\/strong>
The aim of this study was to investigate differences in presence and expression of virulence factors between biotype 1 and 2 strains of 82 Yersinia <\/em>(Y.<\/em>) ruckeri <\/em>isolates, collected from North West Germany during the period of 2004\u20132012, and to analyze the cytotoxicity of these strains to different fish cell lines. The common virulence factor genes, such as yhlA <\/em>and yhlB <\/em>encoding for hemolysin YhlA<\/em>, rucC<\/em> and rupG <\/em>encoding for ruckerbactin, yrp1 <\/em>and yrpDEF <\/em>for ABC exporter protein system, and two flagellar genes, including flgA <\/em>for flagellar secretion chaperones and flhA <\/em>for flagellar secretion apparatus, were found present in both biotype 1 and 2 isolates of Y. ruckeri <\/em>collected from North West Germany using multiplex PCR. mRNA expression of these genes was compared between the two biotypes of Y. ruckeri<\/em>. There was no significant diversity (p gt; 0.05) in the expression of these genes between biotype 1 and 2 strains. 27 Y. ruckeri <\/em>isolates from different typing groups were analysed in cytotoxicity tests to common carp brain (CCB), epithelioma papulosum cyprini (EPC), fathead minnow epithelial (FHM) and rainbow trout gonad-2 (RTG-2) cells, respectively. In vitro cytotoxicity of the isolates to CCB, EPC and FHM was higher than that to RTG-2 (p lt; 0.05). At 15\u00b0C the maximum cytotoxicity to FHM and EPC was higher in non-motile strains than in motile stains after an incubation of 24 h (p lt; 0.05), however, after 48 h, there was no significant difference (p gt; 0.05) of cytotoxicity between those two biotypes. Our results suggest that biotype 2 strains from North West Germany are homogenous with biotype 1 strains on the basis of genetic virulence factor genes. At lower temperature non-motile Y. ruckeri <\/em>isolates were found more active than motile strains, which could explain why in winter non-motile strains were found more often responsible for ERM outbreaks than motile strains. <\/p>

Keywwords<\/strong>
Enteritic red mouth disease, Biotype, cytotoxicity, mRNA expression, Flagellar genes <\/p>

Zusammenfassung<\/strong>
In der vorliegenden Studie wurden 82 Yersinia <\/em>(Y.<\/em>) ruckeri-<\/em>Isolate, die 2004 bis 2012 von Fischen aus Teichwirtschaften in Nord-Westdeutschland isoliert wurden, auf Vorkommen und Expression von Virulenzfaktoren sowie auf Zytotoxizit\u00e4t gegen\u00fcber unterschiedlichen Fischzellen untersucht. Dabei sollten vor allem Unterschiede zwischen Isolaten aus den Biotypen 1 und 2 analysiert werden. Untersucht wurden Gene f\u00fcr beschriebene Virulenzfaktoren: yhlA <\/em>und yhlB<\/em>, die das H\u00e4molysin YhlA <\/em>codieren, rucC <\/em>und rupG<\/em>, die das Ruckerbactin codieren, yrp1<\/em> und yrpDEF<\/em>, die Elemente des ABC-Protein-Exkretionssystems codieren, sowie zwei Gene, die Gei\u00dfel-assoziierte Proteine codieren: flhA<\/em>, das ein Protein des Gei\u00dfel-assoziierten Sekretionsapparates codiert, sowie flgA<\/em>, das ein Gei\u00dfel-assoziiertes Sekretions-Chaperon codiert. Alle Gene lie\u00dfen sich in allen untersuchten Isolaten aus Nord-Westdeutschland mittels Multiplex-PCR nachweisen. Zudem wurde die mRNA-Expression dieser Gene bei Isolaten aus beiden Biotypen von Y. ruckeri <\/em>verglichen. Alle analysierten Gene waren bei den untersuchten Isolaten nicht unterschiedlich exprimiert. Des Weiteren wurden 27 Y. ruckeri<\/em>-Isolate aus unterschiedlichen Typisierungsgruppen in vitro auf ihre Zytotoxizit\u00e4t auf die Fischzelllinen \u201ecommon carp brain\u201c (CCB), Epithelioma papulosum cyprini (EPC), \u201efathead minnow epithelial cells\u201c (FHM), und \u201erainbow trout gonad-2\u201c (RTG-2) gepr\u00fcft. Die Mehrzahl der Y. ruckeri<\/em>-Isolate wies eine geringe In-vitro-Zytotoxizit\u00e4t auf. Die Zytotoxizit\u00e4t war gegen\u00fcber den CCB-, EPC- und FHM-Zellen h\u00f6her als gegen\u00fcber RTG-2-Zellen (p lt; 0,05). Bei 15 \u00b0C war nach 24 h Inkubation die maximale Zytotoxizit\u00e4t nicht motiler Y. ruckeri<\/em>-Isolate gegen\u00fcber EPC- und FHM-Zellen h\u00f6her als bei motilen Isolaten (p lt; 0,05). Nach 48 h Inkubationszeit war kein Unterschied zwischen Isolaten aus beiden Biotypen erkennbar. Unsere Ergebnisse lassen vermuten, dass bei Y. ruckeri<\/em>-Isolaten in Nord-Westdeutschland das Vorkommen von Virulenzfaktoren in beiden Biotypen einheitlich ist. Bei niedrigen Temperaturen scheinen nicht motile Y. ruckeri<\/em>-Isolate eine h\u00f6here Zytotoxizit\u00e4t aufzuweisen, was erkl\u00e4ren k\u00f6nnte, warum diese im Winter h\u00e4ufiger f\u00fcr Ausbr\u00fcche der Rotmaulseuche verantwortlich waren als motile Isolate. <\/p>

Schl\u00fcsselw\u00f6rter:<\/strong>
Rotmaulseuche, Biotyp, Zytotoxizit\u00e4t, mRNA-Expression, Gei\u00dfelassoziierte Gene<\/p>","primaryLanguage":"englisch","summary":"The aim of this study was to investigate differences in presence and expression of virulence factors between biotype 1 and 2 strains of 82 Yersinia <\/em>(Y.<\/em>) ruckeri <\/em>isolates, collected from North West Germany during the period of 2004\u20132012, and to analyze the cytotoxicity of these strains to different fish cell lines. The common virulence factor genes, such as yhlA <\/em>and yhlB <\/em>encoding for hemolysin YhlA<\/em>, rucC<\/em> and rupG <\/em>encoding for ruckerbactin, yrp1 <\/em>and yrpDEF <\/em>for ABC exporter protein system, and two flagellar genes, including flgA <\/em>for flagellar secretion chaperones and flhA <\/em>for flagellar secretion apparatus, were found present in both biotype 1 and 2 isolates of Y. ruckeri <\/em>collected from North West Germany using multiplex PCR. mRNA expression of these genes was compared between the two biotypes of Y. ruckeri<\/em>. There was no significant diversity (p gt; 0.05) in the expression of these genes between biotype 1 and 2 strains. 27 Y. ruckeri <\/em>isolates from different typing groups were analysed in cytotoxicity tests to common carp brain (CCB), epithelioma papulosum cyprini (EPC), fathead minnow epithelial (FHM) and rainbow trout gonad-2 (RTG-2) cells, respectively. In vitro cytotoxicity of the isolates to CCB, EPC and FHM was higher than that to RTG-2 (p lt; 0.05). At 15\u00b0C the maximum cytotoxicity to FHM and EPC was higher in non-motile strains than in motile stains after an incubation of 24 h (p lt; 0.05), however, after 48 h, there was no significant difference (p gt; 0.05) of cytotoxicity between those two biotypes. Our results suggest that biotype 2 strains from North West Germany are homogenous with biotype 1 strains on the basis of genetic virulence factor genes. At lower temperature non-motile Y. ruckeri <\/em>isolates were found more active than motile strains, which could explain why in winter non-motile strains were found more often responsible for ERM outbreaks than motile strains. <\/p>

Keywwords<\/strong>
Enteritic red mouth disease, Biotype, cytotoxicity, mRNA expression, Flagellar genes <\/p>

","zusammenfassung":"In der vorliegenden Studie wurden 82 Yersinia <\/em>(Y.<\/em>) ruckeri-<\/em>Isolate, die 2004 bis 2012 von Fischen aus Teichwirtschaften in Nord-Westdeutschland isoliert wurden, auf Vorkommen und Expression von Virulenzfaktoren sowie auf Zytotoxizit\u00e4t gegen\u00fcber unterschiedlichen Fischzellen untersucht. Dabei sollten vor allem Unterschiede zwischen Isolaten aus den Biotypen 1 und 2 analysiert werden. Untersucht wurden Gene f\u00fcr beschriebene Virulenzfaktoren: yhlA <\/em>und yhlB<\/em>, die das H\u00e4molysin YhlA <\/em>codieren, rucC <\/em>und rupG<\/em>, die das Ruckerbactin codieren, yrp1<\/em> und yrpDEF<\/em>, die Elemente des ABC-Protein-Exkretionssystems codieren, sowie zwei Gene, die Gei\u00dfel-assoziierte Proteine codieren: flhA<\/em>, das ein Protein des Gei\u00dfel-assoziierten Sekretionsapparates codiert, sowie flgA<\/em>, das ein Gei\u00dfel-assoziiertes Sekretions-Chaperon codiert. Alle Gene lie\u00dfen sich in allen untersuchten Isolaten aus Nord-Westdeutschland mittels Multiplex-PCR nachweisen. Zudem wurde die mRNA-Expression dieser Gene bei Isolaten aus beiden Biotypen von Y. ruckeri <\/em>verglichen. Alle analysierten Gene waren bei den untersuchten Isolaten nicht unterschiedlich exprimiert. Des Weiteren wurden 27 Y. ruckeri<\/em>-Isolate aus unterschiedlichen Typisierungsgruppen in vitro auf ihre Zytotoxizit\u00e4t auf die Fischzelllinen \u201ecommon carp brain\u201c (CCB), Epithelioma papulosum cyprini (EPC), \u201efathead minnow epithelial cells\u201c (FHM), und \u201erainbow trout gonad-2\u201c (RTG-2) gepr\u00fcft. Die Mehrzahl der Y. ruckeri<\/em>-Isolate wies eine geringe In-vitro-Zytotoxizit\u00e4t auf. Die Zytotoxizit\u00e4t war gegen\u00fcber den CCB-, EPC- und FHM-Zellen h\u00f6her als gegen\u00fcber RTG-2-Zellen (p lt; 0,05). Bei 15 \u00b0C war nach 24 h Inkubation die maximale Zytotoxizit\u00e4t nicht motiler Y. ruckeri<\/em>-Isolate gegen\u00fcber EPC- und FHM-Zellen h\u00f6her als bei motilen Isolaten (p lt; 0,05). Nach 48 h Inkubationszeit war kein Unterschied zwischen Isolaten aus beiden Biotypen erkennbar. Unsere Ergebnisse lassen vermuten, dass bei Y. ruckeri<\/em>-Isolaten in Nord-Westdeutschland das Vorkommen von Virulenzfaktoren in beiden Biotypen einheitlich ist. Bei niedrigen Temperaturen scheinen nicht motile Y. ruckeri<\/em>-Isolate eine h\u00f6here Zytotoxizit\u00e4t aufzuweisen, was erkl\u00e4ren k\u00f6nnte, warum diese im Winter h\u00e4ufiger f\u00fcr Ausbr\u00fcche der Rotmaulseuche verantwortlich waren als motile Isolate. <\/p>

","schluesselwoerter":["Rotmaulseuche","Biotyp","Zytotoxizit\u00e4t","mRNA-Expression","Gei\u00dfelassoziierte Gene"],"translatedTitle":"Untersuchungen zur In-vitro-Zytotoxizit\u00e4t und zum Nachweis von Virulenzfaktoren mittels Multiplex-PCR bei Yersinia ruckeri- Isolaten aus Teichwirtschaften in Nord-Westdeutschland","abstractE":"The aim of this study was to investigate differences in presence and expression of virulence factors between biotype 1 and 2 strains of 82 Yersinia (Y.) ruckeri isolates, collected from North West Germany during the period of 2004\u20132012, and to analyze the cytotoxicity of these strains to different fish cell lines. The common virulence factor genes, such as yhlA and yhlB encoding for hemolysin YhlA, rucC and rupG encoding for ruckerbactin, yrp1 and yrpDEF for ABC exporter protein system, and two flagellar genes, including flgA for flagellar secretion chaperones and flhA for flagellar secretion apparatus, were found present in both biotype 1 and 2 isolates of Y. ruckeri collected from North West Germany using multiplex PCR. mRNA expression of these genes was compared between the two biotypes of Y. ruckeri. There was no significant diversity (p gt; 0.05) in the expression of these genes between biotype 1 and 2 strains. 27 Y. ruckeri isolates from different typing groups were analysed in cytotoxicity tests to common carp brain (CCB), epithelioma papulosum cyprini (EPC), fathead minnow epithelial (FHM) and rainbow trout gonad-2 (RTG-2) cells, respectively. In vitro cytotoxicity of the isolates to CCB, EPC and FHM was higher than that to RTG-2 (p lt; 0.05). At 15\u00b0C the maximum cytotoxicity to FHM and EPC was higher in non-motile strains than in motile stains after an incubation of 24 h (p lt; 0.05), however, after 48 h, there was no significant difference (p gt; 0.05) of cytotoxicity between those two biotypes. Our results suggest that biotype 2 strains from North West Germany are homogenous with biotype 1 strains on the basis of genetic virulence factor genes. At lower temperature non-motile Y. ruckeri isolates were found more active than motile strains, which could explain why in winter non-motile strains were found more often responsible for ERM outbreaks than motile strains. KeywwordsEnteritic red mouth disease, Biotype, cytotoxicity, mRNA expression, Flagellar genes ","date":{"year":2014,"date":"06\/2014","accepted":"2014-06-27"},"volume":"127","openAccess":false,"journal":"Berliner und M\u00fcnchener Tier\u00e4rztliche Wochenschrift","titleImageId":944,"pages":"233-242","redirects":["in-vitro-cytotoxicity-and-multiplex-pcr-detection-of-virulence-factors-of-yersinia-ruckeri-isolated-from-rainbow-trout-in-north-west-germany\/150\/3130\/79892"],"tierartCategories":[],"artikelartCategories":["Tier\u00e4rztliche Wochenschrift","Abostufe BMTW","Fachartikel"]} CY - Hannover DA - 06/2014 DO - 10.2376/0005-9366-127-233 LA - English N2 - The aim of this study was to investigate differences in presence and expression of virulence factors between biotype 1 and 2 strains of 82 Yersinia (Y.) ruckeri isolates, collected from North West Germany during the period of 2004–2012, and to analyze the cytotoxicity of these strains to different fish cell lines. The common virulence factor genes, such as yhlA and yhlB encoding for hemolysin YhlA, rucC and rupG encoding for ruckerbactin, yrp1 and yrpDEF for ABC exporter protein system, and two flagellar genes, including flgA for flagellar secretion chaperones and flhA for flagellar secretion apparatus, were found present in both biotype 1 and 2 isolates of Y. ruckeri collected from North West Germany using multiplex PCR. mRNA expression of these genes was compared between the two biotypes of Y. ruckeri. There was no significant diversity (p gt; 0.05) in the expression of these genes between biotype 1 and 2 strains. 27 Y. ruckeri isolates from different typing groups were analysed in cytotoxicity tests to common carp brain (CCB), epithelioma papulosum cyprini (EPC), fathead minnow epithelial (FHM) and rainbow trout gonad-2 (RTG-2) cells, respectively. In vitro cytotoxicity of the isolates to CCB, EPC and FHM was higher than that to RTG-2 (p lt; 0.05). At 15°C the maximum cytotoxicity to FHM and EPC was higher in non-motile strains than in motile stains after an incubation of 24 h (p lt; 0.05), however, after 48 h, there was no significant difference (p gt; 0.05) of cytotoxicity between those two biotypes. Our results suggest that biotype 2 strains from North West Germany are homogenous with biotype 1 strains on the basis of genetic virulence factor genes. At lower temperature non-motile Y. ruckeri isolates were found more active than motile strains, which could explain why in winter non-motile strains were found more often responsible for ERM outbreaks than motile strains. KeywwordsEnteritic red mouth disease, Biotype, cytotoxicity, mRNA expression, Flagellar genes PB - Schlütersche Verlagsgesellschaft mbH & Co. KG PP - Hannover PY - 2014 SP - 233 EP - 242 T1 - In vitro cytotoxicity and multiplex PCR detection of virulence factors of Yersinia ruckeri isolated from rainbow trout in North West Germany T2 - Berliner und Münchener Tierärztliche Wochenschrift TI - In vitro cytotoxicity and multiplex PCR detection of virulence factors of Yersinia ruckeri isolated from rainbow trout in North West Germany TT - Untersuchungen zur In-vitro-Zytotoxizität und zum Nachweis von Virulenzfaktoren mittels Multiplex-PCR bei Yersinia ruckeri- Isolaten aus Teichwirtschaften in Nord-Westdeutschland VL - 127 SN - 0005-9366 ER -