Header

UZH-Logo

Maintenance Infos

Antimicrobial susceptibility of porcine brachyspira hyodysenteriae isolates from Switzerland


Kirchgässner, Constanze. Antimicrobial susceptibility of porcine brachyspira hyodysenteriae isolates from Switzerland. 2016, University of Zurich, Vetsuisse Faculty.

Abstract

The anaerobic spirochaete Brachyspira (B.) hyodysenteriae is the causative agent of swine dysentery (SD), a severe mucohaemorrhagic diarrheal disease in pigs worldwide. Currently, no data for antimicrobial susceptibility of B. hyodysenteriae from Switzerland are available and though antimicrobial treatment is the main therapy, no standardised methods for antimicrobial susceptibility testing are established. Therefore, a broth microdilution test was performed for 30 Swiss porcine field isolates and evaluated for its suitability in diagnostics. For the pleuromutilins, tiamulin and valnemulin, a good reproducibility in testing and susceptibility at low concentrations could be observed. The reproducibility for doxycycline was acceptable. A part of the isolates showed reduced susceptibility. For lincomycin and the macrolides, tylosin and tylvalosin, reproducibility was influenced by the occurrence of so-called skips. Furthermore, reduced susceptibility for lincomycin and resistance for tylosin could be detected. Sequencing of the 23S rDNA revealed, that a point mutation is responsible for resistance and a possible explanation for the skipped wells. In a European comparison Switzerland is still in a favourable situation. However, accurate determination of minimal inhibitory concentrations is questionable, and a classification of isolates into susceptible and resistant isolates is difficult due to the lack of unambiguous classification criteria.

Abstract

The anaerobic spirochaete Brachyspira (B.) hyodysenteriae is the causative agent of swine dysentery (SD), a severe mucohaemorrhagic diarrheal disease in pigs worldwide. Currently, no data for antimicrobial susceptibility of B. hyodysenteriae from Switzerland are available and though antimicrobial treatment is the main therapy, no standardised methods for antimicrobial susceptibility testing are established. Therefore, a broth microdilution test was performed for 30 Swiss porcine field isolates and evaluated for its suitability in diagnostics. For the pleuromutilins, tiamulin and valnemulin, a good reproducibility in testing and susceptibility at low concentrations could be observed. The reproducibility for doxycycline was acceptable. A part of the isolates showed reduced susceptibility. For lincomycin and the macrolides, tylosin and tylvalosin, reproducibility was influenced by the occurrence of so-called skips. Furthermore, reduced susceptibility for lincomycin and resistance for tylosin could be detected. Sequencing of the 23S rDNA revealed, that a point mutation is responsible for resistance and a possible explanation for the skipped wells. In a European comparison Switzerland is still in a favourable situation. However, accurate determination of minimal inhibitory concentrations is questionable, and a classification of isolates into susceptible and resistant isolates is difficult due to the lack of unambiguous classification criteria.

Statistics

Downloads

188 downloads since deposited on 27 Dec 2016
119 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Dissertation (monographical)
Referees:Wittenbrink Max Michael, Siedler Xaver
Communities & Collections:05 Vetsuisse Faculty > Institute of Veterinary Bacteriology
Dewey Decimal Classification:570 Life sciences; biology
Language:English
Date:November 2016
Deposited On:27 Dec 2016 07:36
Last Modified:02 Feb 2018 11:06
Number of Pages:55
OA Status:Green
Related URLs:https://www.recherche-portal.ch/ZAD:default_scope:ebi01_prod010802531 (Library Catalogue)

Download

Download PDF  'Antimicrobial susceptibility of porcine brachyspira hyodysenteriae isolates from Switzerland'.
Preview
Content: Published Version
Filetype: PDF
Size: 6MB