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Actinobacillus (A.) pleuropneumoniae is the etiological agent of porcine pleuropneumonia, a respiratory infectious disease responsible for global economic losses in the pig industry. From a monitoring perspective as well as due to the different courses of disease associated to the various serovars, it is essential to distinguish them in different herds or countries. In this study, we developed a novel high resolution melting (HRM) assay based on reference strains for each of the 19 known serovars and additional 15 clinical A. pleuropneumoniae isolates. The novel HRM comprises the species-specific APP-HRM1 and two serovar-specific HRM assays (APP-HRM2 and APP-HRM3). APP-HRM1 allowed PCR amplification of apxIV resulting in an A. pleuropneumoniae specific melting curve, while nadV specific primers clearly differentiated biovar 2 from biovar 1 isolates. Using APP-HRM2 and APP-HRM3, 13 A. pleuropneumoniae serovars can be determined inspecting the assigned melting temperature. In contrast, serovar 3 and 14, serovar 9 and 11, and serovar 5 and 15 have partly overlapping melting temperatures and thus represent a challenge to accurately distinguish them. Consequently, to unambiguously ensure the correct assignment of the serovar, it is recommended to perform the serotyping HRM assay using a positive control for each serovar. This rapid and user-friendly assay showed high sensitivity with 1.25 fg - 125 pg of input DNA and a specificity of 100% to identify A. pleuropneumoniae. Characteristic melting patterns of amplicons might allow detecting new serovars. The novel HRM assay has the potential to be implemented in diagnostic laboratories for better surveillance of this pathogen.

Glaesserella parasuis is the etiological agent of Glässer’s disease, which is associated with polyserositis and arthritis and has a significant impact on the economy of the pig production industry. For the optimal surveillance of this pathogen, as well as for the investigation of G. parasuis-associated diseases, it is crucial to identify G. parasuis at the serovar level. In this work, we designed and developed new high-resolution melting (HRM) approaches, namely, the species-specific GPS-HRM1 and two serovar-specific HRM assays (GPS-HRM2 and GPS-HRM3), and evaluated the sensitivity and specificity of the assays. The HRM assays demonstrated good sensitivity, with 12.5 fg–1.25 pg of input DNA for GPS-HRM1 and 125 fg–12.5 pg for GPS-HRM2 and GPS-HRM3, as well as a specificity of 100% for the identification of all recognized 15 G. parasuis serovars. Eighteen clinical isolates obtained between 2014 and 2022 in Switzerland were tested by applying the developed HRM assays, which revealed a heterogeneous distribution of serovars 2, 7, 4, 13, 1, and 14. The combination with virulence marker vtaA (virulence-associated trimeric autotransporters) allows for the prediction of potentially virulent strains. The assays are simple to execute and enable a reliable low-cost approach, thereby refining currently available diagnostic tools.

Additional file 4. Alignment of target gene sequences and the corresponding amino acid sequences used by pathotyping. Sequence alignment of copper ATPase 1-gene (A and B) and partial gene sequence alignment of type I RM system S protein-gene (C and D) of invasive disease-associated isolates of Swiss S. suis in comparison to the highly virulent reference strain P1/7 are shown visualizing different gene variants and its corresponding protein sequences. Conserved, matching nucleotide residues are illustrated as blue dots, whereas red represents differences of nucleotide sequences. (A) Copper ATPase 1-gene sequences of S. suis PP463 (cps2, ST28), SS470 (cps1/2, ST28), PP423 (cps1/2, ST1133), and PP536 (cps9, ST1105) are represented. Primer sequences of the pathotyping tool are indicated in green. A duplication of a 54 bp long DNA segment in isolate SS470 and deletion of a 21 bp fragment in all represented Swiss isolates could be observed, illustrating a high genetic variability. (B) Corresponding amino acid sequence alignment of Copper ATPase 1 is shown. (C) RM system S protein gene sequences of S. suis PP463 (cps2, ST28), PP423 (cps1/2, ST1133), and PP269 (cps1, ST13) are represented. The forward primer is indicated in green, whereas the reverse primer could not be shown since illustrated Swiss isolates are truncated. (D) Corresponding amino acid sequence alignment of RM systems S protein is shown.

Actinobacillus pleuropneumoniae serotype 19 is a very recently described new serotype with a novel type II capsule locus. Here, we report the draft genome sequences of two Actinobacillus pleuropneumoniae serotype 19 strains with a serogroup 3/6/8/12/15 O-antigen locus that were isolated in 2018 and 2021 from two different pig farms in Switzerland.

A 2-year-old European shorthair cat was presented with a nonhealing skin lesion on the right abdominal wall. Repeated surgical excision and antimicrobial treatment with cefovecin, clindamycin, and trimethoprim-sulfamethoxazole did not lead to clinical improvement. Histopathology of the skin lesion showed pyogranulomatous dermatitis and panniculitis. Definitive diagnosis was made by mycobacterial culture and rpoB sequencing, revealing Mycobacterium abscessus subsp. abscessus. To the authors��� knowledge, this is the first report of Mycobacterium abscessus subsp. abscessus infection in a cat in Switzerland and the second case in Europe. The isolated strain carried a functional erm(41) gene that confers inducible macrolide resistance. Further phenotypic resistances to doxycycline, minocycline, and imipenem were detected, resulting in little chance of successful antimicrobial treatment. Mycobacterium abscessus subsp. abscessus is an emerging pathogen in human medicine and poses a non-negligible zoonotic risk for the owners of the cat.

The following case report describes the clinical and diagnostic procedure for suspected brucellosis infection in a dog. A 21 month old intact male Border Collie was presented with an enlarged right testicle and epididymis. The dog was imported to Switzerland from Germany at the age of three months, but was never abroad since then. Clinical and laboratory diagnostic investigation included bacteriology and histology. An initial serological evaluation by means of rapid slide agglutination test (RSAT) was negative. Repeated examination of the same serum by a chromatographic immunoassay (ICT) revealed a positive result. Brucella canis infection was confirmed by culture. The present case is intended to underline the importance of the suspected diagnosis of 'brucellosis' in the presence of reproductive tract problems in dogs. In addition, Brucella canis has zoonotic potential and it is imperative to comply with strict hygiene management.Der nachfolgende Fallbericht beschreibt das klinische und diagnostische Vorgehen bei Verdacht auf Brucellose bei einem Hund. Ein 21 Monate alter intakter Border Collie Rüde wurde mit vergrössertem rechten Hoden und Nebenhoden vorgestellt. Der Hund wurde mit drei Monaten aus Deutschland in die Schweiz importiert, war aber ansonsten nie im Ausland. Es erfolgte eine klinische sowie labordiagnostische Untersuchung inklusive Bakteriologie und Histologie. Eine erste serologische Abklärung mittels rapid slide agglutination test (RSAT) war negativ. Eine wiederholte Untersuchung desselben Serums mittels eines chromatographischen Immunoassay (ICT) ergab ein positives Resultat. Mittels kulturellem Nachweis wurde der Verdacht einer Infektion mit Brucella canis bestätigt. Der vorliegende Fall soll die Wichtigkeit der Verdachtsdiagnose ‚Brucellose‘ bei Vorliegen von Problemen des Reproduktionstraktes bei Hunden unterstreichen. Desweitern hat Brucella canis zoonotisches Potential und es ist zwingend ein strenges Hygienemanagement einzuhalten.Le rapport de cas suivant décrit la procédure clinique et diagnostique en cas de suspicion d’infection par la brucellose chez un chien. Un Border Collie mâle intact de 21 mois a été présenté avec un grossissement du testicule et de l’épididyme droits. Le chien avait été importé d’Allemagne en Suisse à l’âge de trois mois, mais n’avait si non jamais été à l’étranger depuis lors. Des examens diagnostiques cliniques et de laboratoire, notamment bactériologie et histologie ont été effectués. Une première évaluation sérologique au moyen du test d’agglutination rapide sur lame (RSAT) était négative. Un examen ultérieur du même sérum par une immunoanalyse chromatographique (ICT) a révélé un résultat positif. L’infection à Brucella canis a été confirmée par culture. Le présent cas souligne l’importance du diagnostic présumé de «brucellose» en présence de problèmes de l›appareil reproducteur chez le chien. De plus, Brucella canis a un potentiel zoonotique et il est impératif d’appliquer des mesures d’hygiène strictes.Il seguente studio descrive la procedura clinica e la diagnosi per una sospetta infezione da brucellosi in un cane. Un Border Collie maschio di 21 mesi intatto è stato presentato con un ingrossato testicolo destro ed epididimo. Il cane è stato importato in Svizzera dalla Germania all’età di tre mesi, e mai trasportato all’estero da quel momento. Sono state effettuate indagini cliniche e di laboratorio, comprese batteriologia e istologia. Un’iniziale valutazione sierologica mediante il rapid slide agglutination test (RSAT) è risultata negativa. ­L’esame ripetuto dello stesso siero mediante immunodosaggio cromatografico (ICT) ha rivelato un risultato positivo. L’infezione da Brucella canis è stata confermata dalla coltura. Il presente caso intende sottolineare l’importanza della sospetta diagnosi di “brucellosi” in presenza di problemi del tratto riproduttivo nei cani. Inoltre, Brucella canis ha un potenziale zoonotico ed è imperativo rispettare una rigorosa gestione dell’igiene.

Public interest in animal tuberculosis is mainly focused on prevention and eradication of bovine tuberculosis in cattle and wildlife. In cattle, immunodiagnostic tests such as the tuberculin skin test or the interferon gamma (IFN-γ) assay have been established and are commercially available. Feline tuberculosis is rather unknown, and the available diagnostic tools are limited. However, infections with Mycobacterium tuberculosis complex members need to be considered an aetiological differential diagnosis in cats with granulomatous lymphadenopathy or skin nodules and, due to the zoonotic potential, a time-efficient and accurate diagnostic approach is required. The present study describes 11 independent cases of Mycobacterium microti infection in domestic cats in Switzerland. For three cases, clinical presentation, diagnostic imaging, bacteriological results, immunodiagnostic testing, and pathological features are reported. An adapted feline IFN-γ release assay was successfully applied in two cases and appears to be a promising tool for the ante mortem diagnosis of tuberculosis in cats. Direct contact with M. microti reservoir hosts was suspected to be the origin of infection in all three cases. However, there was no evidence of M. microti infection in 346 trapped wild mice from a presumptive endemic region. Therefore, the source and modalities of infection in cats in Switzerland remain to be further elucidated.