Distribution, genetic heterogeneity, and antimicrobial susceptibility of Brachyspira pilosicoli in Swiss pig herds.

Brachyspira (B.) pilosicoli is a bacterium causing porcine intestinal spirochaetosis, a disease characterized by diarrhoea and depressed growth rates especially in nursery and fattening pigs. Knowledge of the epidemiology and antimicrobial susceptibility of this pathogen is limited. Therefore, the aim of this study was to analyse the distribution, genetic heterogeneity, and antimicrobial susceptibility of B. pilosicoli field isolates from Swiss pig farms. Faecal swabs of 693 animals originating from 156 herds were analysed for the presence of Brachyspira spp. using culture and polymerase chain reaction identification. Further characterisation was performed using multilocus sequence typing (MLST) and broth dilution antimicrobial susceptibility testing. With 52.6% positive herds, B. pilosicoli could be frequently isolated from herds with animals suffering from diarrhoea. In herds with animals without clinical signs of diarrhoea, detection was significantly less frequent with only 10.5% positive herds (p 0.001). Among 80 isolates used for typing, genetic heterogeneity was observed with 44 different sequence types (ST) which often differed from herd to herd. No predominant ST was observed. More than 73.0% of the 41 B. pilosicoli isolates analysed, showed minimal inhibitory concentration values above the wild type cut-off values for lincomycin, tylvalosin and/ or tylosin. For tiamulin, valnemulin and doxycycline, this was the case in 48.8%, 43.9% and 36.6%, respectively. In conclusion, a diverse population of B. pilosicoli exhibited decreased susceptibility to antimicrobials used against Brachyspira infections. Monitoring of resistance in Brachyspira spp. is highly recommended to support targeted use of antimicrobials in pigs.

[Retrospective study on the eradication of Swine Dysentery (Brachyspira hyodysenteriae) in Switzerland]. / Retrospektive Studie zur Sanierung von Beständen mit Schweinedysenterie (Brachyspira hyodysenteriae) in der Schweiz.

INTRODUCTION: The eradication of Swine Dysentery (infection with Brachyspira hyodysenteriae) within farm populations is extremely complex and its success is significantly linked to the compliance of pig farmers performing the onsite eradications, emphasizing the importance of their motivation. The present study focuses on the motivation and satisfaction of Swiss pig farmers concerning eradication of Swine Dysentery on their farms and has the intention of generating data to establish a basis for decision-making regarding future eradications. A structured survey was conducted on 68 Swiss pig farms where an eradication of Swine Dysentery had already taken place. The data collected were then statistically analyzed. Of the study's population, 50 (73.5%) farms underwent eradication using the total depopulation method and 18 (26.5%) farms conducted an eradication process using the partial depopulation method; both in accordance to the guidelines of Switzerland's Pig Health Service (SUISAG Schweinegesundheitsdienst; SGD). When asked about the driving factors behind their decision to perform the eradications, owners cited their own interest (57.4%; 39/68) (primarily due to financial aspects (38.5%; 15/39)) or external pressure (42.7%; 29/68) (predominantly through marketers as well as through the health status assigned by the SGD (each 11/29)). The duration of the eradication on farms differed significantly and costs varied considerably within the different production types as well as the type of eradication performed. Utilized means and processes for eradication were the same (drugs, disinfectant for manure) or much alike (e.g. emptying of the pigpens) however stock-specific and individual variations were exhibited. The majority of the interviewed livestock owners were motivated to perform the eradication (86.6%; 58/67), satisfied with having performed the eradication and satisfied with the outcome of the eradication (89.7%; 61/68). The cost efficiency of the farms (54.4%; 37/68) and the health status of the herds (63.2%; 43/68) were perceived as having improved and the usage of drugs having diminished (59.7%; 40/67) post eradication. The effort of an eradication was described as acceptable to too great. The study showed herd eradication of Swine Dysentery to be perceived as mainly positive. However, effort as well as costs are felt to be considerable and could, therefore, provide the most important starting point to increasing the willingness of pig owners to perform eradications.

INTRODUCTION: L'assainissement d'exploitations avec de problèmes de dysenterie porcine (infection à Brachyspira hyodysenteriae) peut prendre beaucoup de temps et son succès est étroitement lié à l'observance des personnes qui l'exécutent. C'est pourquoi les éleveurs de porcs doivent être motivés pour effectuer cette lutte. La présente étude a notamment porté sur la motivation et la satisfaction des détenteurs suisses de porcs en ce qui concerne l'assainissement de la dysenterie porcine afin de générer des données et, partant, des aides à la décision pour de futures mesures de lutte. Pour cela, des données ont été collectées au moyen d'un entretien structuré et analysées statistiquement dans 68 exploitations suisses après un assainissement complet de la dysenterie. Dans ces exploitations, 50 assainissements totaux (73.5%) et 18 assainissements partiels (26,5%) ont été effectués conformément aux directives du Service sanitaire porcin suisse (SUISAG SGD). L'intérêt propre (57,4%, 39/68) (principalement dû aux aspects financiers (38,5%; 15/39)) et la pression externe (42,7%; 29/68) (principalement par statut SGD ou par les négociants (chacun pour 11/29)) étaient les raisons de l'assainissement. La durée de l'assainissement et les coûts variaient considérablement selon les types de production de même que selon les types d'assainissement. Dans le cadre de l'assainissement, les moyens utilisés et les processus étaient les mêmes (médicaments, désinfectant de fumier) respectivement étaient similaires (par exemple, la vidange des écuries) mais présentait des variations individuelles spécifiques à l'exploitation. La majorité des propriétaires d'animaux interrogés étaient motivés à un assainissement (86,6%, 58/67) et étaient également satisfaits de l'avoir fait (97,1%, 66/68) et du résultat (89,7%, 61/68). Après l'assainissement, la rentabilité (54,4%; 37/68) et la santé du cheptel (63,2%; 43/68) ont été jugées subjectivement meilleures et la consommation de médicaments (59,7%; 40/67) inférieure. Le coût de l'assainissement était, selon le type de production, considéré comme justifié jusqu'à élevé. On a pu montrer que l'assainissement de la dysenterie porcine est généralement évalué positivement. Cependant, les efforts et les coûts sont considérables et représentent des points de départ possibles pour optimiser la volonté des éleveurs de porcs.

Isolation of Brachyspira hyodysenteriae from a crow (Corvus corone) in close proximity to commercial pigs.

The aim of this study was to determine whether crows (Corvus corone) can harbour Brachyspira hyodysenteriae, the cause of swine dysentery, and whether the organism carried by crows is related to strains infecting pigs. B. hyodysenteriae was isolated from one crow in close proximity to two pig farms in Switzerland. This isolate, along with five isolates of B. hyodysenteriae from one of the farms, belonged to sequence type (ST) 66 using multilocus sequence typing. This finding suggests that crows are potential vectors of B. hyodysenteriae, but further studies will be necessary to clarify the role of crows in the epidemiology of this organism.

Occurrence of Brachyspira hyodysenteriae in multiplier pig herds in Switzerland.

OBJECTIVE: This research was aimed to determine the occurrence of Brachyspira (B.) hyodysenteriae in Swiss multiplier pig herds. MATERIALS AND METHODS: In a pilot study a direct real-time polymerase chain reaction (PCR) method for B. hyodysenteriae was compared to culture followed by PCR on 106 samples from three herds. Subsequently 40 multiplier herds were epidemiologically characterized and analysed for the presence of B. hyodysenteriae using direct PCR on 1412 rectal swabs. For external validation 20 swabs obtained from two positive conventional herds were analysed. RESULTS: The comparison of direct PCR with culture followed by PCR resulted in a moderate agreement (kappa index: 0.58). In the two conventional herds, 35% of the samples (7/20) tested positive. Samples from 39 multipliers tested negative. In one multiplier herd, 25% (9/36) of the samples tested PCR positive. Risk factors in the multiplier herd may have been rodents or birds, but not pig purchase. CONCLUSION AND CLINICAL RELEVANCE: B. hyodysenteriae have been detected in a Swiss multiplier herd, which underlines the threat of potential spread by replacement pigs. Consequently, a Brachyspira monitoring programme was established for Swiss multiplier herds.

[Swine dysentery eradication in a grower-finisher farm in Switzerland]. / Die Sanierung der Schweinedysenterie in einem Schweizer Aufzucht-Mastbetrieb.

On a Swiss grower-finisher farm blood-tinged-diarrhoea in pigs weighing 40 to 60 kg was observed during several months, resulting in reduced feed efficiency and a prolonged fattening period. As part of a research project, in February 2007 faecal samples were analysed and one diseased pig was euthanised and sent for necropsy where typical gut lesions indicative for a Brachyspira (B.) hyodysenteriae infection were found. B. hyodysenteriae was demonstrated by PCR in 4 out of 5 faecal samples. The pig farm thereafter underwent an eradication process with timed depopulation of the consecutive pigpens. During February to June 2008 the farm was regularly inspected and tested for B. hyodysenterieae. Testing continued for another year after the eradication process and all faecal samples proved negative. Until January 2010 neither diarrhoea with blood nor B. hyodysenterieae reoccurred.

[Mucormycosis due to Mycocladus corymbiferus in a fattening pig]. / Mucormykose durch Mycocladus corymbiferus bei einem Mastschwein.

A fattening pig with enlarged head and abdominal lymph nodes was examined. An aspirate of the abscesses did not produce a conclusive diagnosis. Only an excision with subsequent histological and bacteriological examination showed the mould Mycocladus corymbiferus (syn. Absidia corymbifera) to be present. Similar abscesses should be examined as actinomycosis and leucosis are the main differential diagnoses.

[Field validation of a real-time PCR test for the detection of Mycoplasma hyopneumoniae in nasal swabs of live pigs]. / Feldvalidierung einer real-time PCR zum Nachweis von Mycoplasma hyopneumoniae in Nasentupfermaterial von lebenden Schweinen.

Enzootic pneumonia (EP) of pigs, caused by Mycoplasma hyopneumoniae has been a notifiable disease in Switzerland since May 2003. The diagnosis of EP has been based on multiple methods, including clinical, bacteriological and epidemiological findings as well as pathological examination of lungs (mosaic diagnosis). With the recent development of a real-time PCR (rtPCR) assay with 2 target sequences a new detection method for M. hyopneumoniae became available. This assay was tested for its applicability to nasal swab material from live animals. Pigs from 74 herds (average 10 pigs per herd) were tested. Using the mosaic diagnosis, 22 herds were classified as EP positive and 52 as EP negative. From the 730 collected swab samples we were able to demonstrate that the rtPCR test was 100% specific. In cases of cough the sensitivity on herd level of the rtPCR is 100%. On single animal level and in herds without cough the sensitivity was lower. In such cases, only a positive result would be proof for an infection with M. hyopneumoniae. Our study shows that the rtPCR on nasal swabs from live pigs allows a fast and accurate diagnosis in cases of suspected EP.