Transferrin (TF)-mediated provision of iron is essential for a productive infection by many bacterial pathogens, and iron-depletion of TF is a first line defence against bacterial infections. Therefore, the transferrin (TF) gene can be considered a candidate gene for disease resistance. We obtained the complete DNA sequence of the porcine TF gene, which spans 40 kb and contains 17 exons. We identified polymorphisms on a panel of 10 different pig breeds. Comparative intra- and interbreed sequence analysis revealed 62 polymorphisms in the TF gene including one microsatellite. Ten polymorphisms were located in the coding sequence of the TF gene. Four SNPs (c.902A>T, c.980G>A, c.1417A>G, c.1810A>C) were predicted to cause amino acid exchanges (p.Lys301Ile, p.Arg327Lys, p.Lys473Glu, p.Asn604His). We performed association analyses using six selected TF markers and 116 pigs experimentally infected with Actinobacillus pleuropneumoniae serotype 7. The analysis showed breed-specific TF allele frequencies. In German Landrace, we found evidence for a possible association of the severity of A. pleuropneumoniae infection with TF genotypes.

Conducting antimicrobial susceptibility testing (AST) in a comparable manner requires the availability of a standardized method. Organizations, such as the Clinical and Laboratory Standards Institute (CLSI) or the European Committee on Antimicrobial Susceptibility Testing (EUCAST), provide standardized protocols for a range of fastidious bacteria but not for Mycoplasma hyorhinis. We developed a broth microdilution method for testing M. hyorhinis in a standardized and harmonized way using a modified Friis broth devoid of antimicrobial or otherwise bacterial growth-inhibiting agents. The type strain M. hyorhinis DSM 25591 was chosen to establish the methodology. The antimicrobial agents of interest were doxycycline, enrofloxacin, erythromycin, florfenicol, gentamicin, marbofloxacin, tetracycline, tiamulin, tilmicosin, tulathromycin, and tylosin, tested by using commercial SensititreTM microtiter plates. In addition, the suitability of the methodology was evaluated via variation of the individual ingredients of the modified Friis broth by either using different batches or choosing other distributors. Despite these alterations, the method provided reliable results. We obtained repeatable minimal inhibitory concentrations for all six tested field isolates and the M. hyorhinis type strain. With this newly proposed method, we aim to provide an improved AST method for diagnostic laboratories and monitoring purposes with better comparability between times and countries. In addition, this new method will allow for an improvement of targeted treatments using antimicrobial agents and thereby reduce the options for resistance development.

Actinobacillus (A.) pleuropneumoniae is one of the most important respiratory pathogens in global pig production. Antimicrobial treatment and vaccination provide only limited protection, but genetic disease resistance is a very promising alternative for sustainable prophylaxis. Previous studies have discovered multiple QTL that may explain up to 30% of phenotypic variance. Based on these findings, the aim of the present study was to use genomic sequencing to identify genetic markers for resistance to pleuropneumonia in a segregating commercial German Landrace line. 163 pigs were infected with A. pleuropneumoniae Serotype 7 through a standardized aerosol infection method. Phenotypes were accurately defined on a clinical, pathological and microbiological basis. The 58 pigs with the most extreme phenotypes were genotyped by sequencing (next-generation sequencing). SNPs were used in a genome-wide association study. The study identified genome-wide associated SNPs on three chromosomes, two of which were chromosomes of QTL which had been mapped in a recent experiment. Each variant explained up to 20% of the total phenotypic variance. Combined, the three variants explained 52.8% of the variance. The SNPs are located in genes involved in the pathomechanism of pleuropneumonia. This study confirms the genetic background for the host's resistance to pleuropneumonia and indicates a potential role of three candidates on SSC2, SSC12 and SSC15. Favorable gene variants are segregating in commercial populations. Further work is needed to verify the results in a controlled study and to identify the functional QTN.

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The draft genome sequences of three Streptococcus suis isolates, IMT40343, IMT40201, and IMT40738, are presented here. These isolates were obtained from bronchoalveolar lavage fluid of healthy and diseased weaners from different German piglet-producing farms and differed in their susceptibility to penicillin.

ZusammenfassungHautveränderungen werden sowohl durch Einflüsse der Umgebung als auch durch Erkrankungen des Tieres verursacht. Einige Erkrankungen manifestieren sich primär in der Haut, andere bedingen durch eine systemische Infektion sekundäre Veränderungen der Haut. Entsprechend ihrer Genese lassen sich Hauterkrankungen des Schweines in kongenitale, infektiöse, alimentäre und haltungsbedingte Erkrankungen einteilen. Hinzu kommen Erkrankungen der Haut mit bislang ungeklärter Ursache. Hauterkrankungen können im Schweinebestand durch reduzierte Futteraufnahme, Wachstumsdepression und erhöhte Mortalität zu wirtschaftlichen Verlusten führen. Die Kenntnis der in Betracht kommenden Ursachen, der Symptomatik sowie der Auswahl der weiterführenden Laboruntersuchungen ermöglicht eine fundierte Diagnostik und eine rasche, effektive Therapie. Die Darstellung verschiedener Hautkrankheiten soll hierfür eine entsprechende Grundlage bieten.

Zusammenfassung Gegenstand und Ziel: In der Veterinärmedizin hat die computertomographische (CT-) Bildgebung in den letzten Jahren für die Diagnostik bei Liebhabertieren, aber auch für Verlaufsuntersuchungen an Tiermodellen für die Humanmedizin an Bedeutung gewonnen. In dieser Studie wurde die Eignung der CT als bildgebendes Verfahren für die Darstellung des Thorax und insbesondere der Lunge beim Schwein geprüft. Material und Methoden: An 11 gesunden Schweinen zweier Altersgruppen erfolgten CT-Untersuchungen. Die erhobenen Befunde wurden zu klinischen, röntgenologischen, makroskopischen und mikroskopischen Untersuchungsbefunden sowie zur Erregerdiagnostik in Beziehung gesetzt und evaluiert. Ergebnisse: Anhand transversaler Schnittbilder wurden klinisch relevante anatomische Strukturen dargestellt und beschrieben. Die Dichtemessungen des Lungenparenchyms in Höhe des zweiten, vierten und siebten Brustwirbels zeigten in Bauchlagerung der Tiere eine signifikant höhere Lungenparenchymdichte der ventralen Quadranten im Vergleich zu den dorsalen Quadranten. Schlussfolgerung und klinische Relevanz: Die CT-Untersuchung eignet sich zur kontrastreichen und überlagerungsfreien Darstellung der Lunge des Schweines. Diese Referenz für die Lunge gesunder Schweine stellt eine Bewertungsgrundlage dar, um zukünftig anatomische Strukturen der Schweinelunge im CT-Querschnittbild identifizieren und pathologische Veränderungen bewerten zu können.