Quality-Control Ranges for Antimicrobial SusceptibilityTesting by Broth Dilution of the<i> Brachyspira hyodysenteriae</i> Type Strain (ATCC 27164<sup>T</sup>)

Pringle, Märit; Aarestrup, Frank Møller; Bergsjø, Bjarne; Fossi, Marja; Jouy, Éric; Landén, Annica; Mevius, Dik; Perry, Karen L; Teale, Christopher; Thomson, Jill R.; Skrzypczak, Teresa; Veldman, Kees; Franklin, A.

doi:10.1089/mdr.2006.12.219

Cited by 18 publications

(22 citation statements)

References 3 publications

(3 reference statements)

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“…All tests were performed with the identical broth dilution method and in 96 separate tests the MICs for the control strain were within proposed ranges [6]. For pleuromutilins, this method has been compared with agar dilution [10].…”

Section: Resultsmentioning

confidence: 99%

“…A broth dilution method has been evaluated [5] and is used at the National Veterinary Institute (SVA) in Sweden for monitoring of antimicrobial susceptibility in Brachyspira spp. Minimum inhibitory concentration (MIC) quality control ranges for the type strain of B. hyodysenteriae , B78 T (ATCC® 27164 T ), has been established in an inter-laboratory study for this method [6]. However no criteria for interpretation of the results from susceptibility tests of Brachyspira spp.…”

Section: Introductionmentioning

confidence: 99%

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Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010

et al. 2012

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BackgroundThe anaerobic spirochetes Brachyspira hyodysenteriae and Brachyspira pilosicoli cause diarrheal diseases in pigs. Their fastidious nature has hampered standardization of methods for antimicrobial susceptibility testing. For monitoring of antimicrobial susceptibility wild type cutoff values are needed to define where the wild type distribution of MICs ends and no approved cutoffs are available for Brachyspira spp. In this study antimicrobial susceptibility data for both species (in total 906 isolates) were compiled and analyzed and wild type cut off values for B. hyodysenteriae proposed.MethodsThe MICs of tiamulin, valnemulin, tylosin, tylvalosin, doxycycline and lincomycin were determined by broth dilution in brain heart infusion broth supplemented with 10% fetal calf serum.ResultsThe compiled MICs from the broth dilution tests of the B. hyodysenteriae type strain, B78T (ATCC® 27164T), showed that the method yields reproducible results. In an international perspective the frequencies of isolates with decreased antimicrobial susceptibility were low among both B. hyodysenteriae and B. pilosicoli. However, in B. pilosicoli a constant level of 10-15% isolates with tiamulin MICs >4 μg/ml was detected between 2002 and 2010 and in B. hyodysenteriae a gradual increase in tiamulin MICs was seen between 1990 and 2003 although this increase has ceased during the last years. The wild type cutoff values proposed for B. hyodysenteriae are: tiamulin >0.25 μg/ml, valnemulin >0.125 μg/ml, tylosin >16 μg/ml, tylvalosin >1 μg/ml, lincomycin >1 μg/ml and doxycycline >0.5 μg/ml.ConclusionsThe broth dilution method used in this study has over the years generated tightly grouped MIC populations for the field isolates and reproducible results for the control strain B78T and is therefore a suitable antimicrobial susceptibility test method for monitoring of Brachyspira spp. Here we propose wild type cutoff values for six antimicrobial agents for B. hyodysenteriae tested by broth dilution based on MIC distributions and the current knowledge on mechanisms of resistance in this species. There are few studies on antimicrobial resistance mechanisms and MIC distributions in B. pilosicoli but to some extent the cutoff values proposed for B. hyodysenteriae may be applicable also for monitoring of antimicrobial susceptibility in B. pilosicoli.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010

et al. 2012

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“… a Approved quality control ranges by the CLSI for susceptibility tests performed by micro dilution in Mueller Hinton broth [ 25 , 26 ]. b Proposed quality-control ranges by Pringle et al for susceptibility tests performed in brain heart infusion broth with 10% fetal calf serum [ 24 ]. …”

Section: Resultsmentioning

confidence: 99%

Isolation and characterization of Treponema phagedenis-like spirochetes from digital dermatitis lesions in Swedish dairy cattle

et al. 2008

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Background: Digital dermatitis in cattle is an emerging infectious disease. Ulcerative lesions are typically located on the plantar skin between the heel bulbs and adjacent to the coronet. Spirochetes of the genus Treponema are found in high numbers in the lesions and are likely to be involved in the pathogenesis. The aim of this study was to obtain pure cultures of spirochetes from cattle with digital dermatitis and to describe them further.

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“…However, the interpretation of MIC values is still difficult and there are no approved standards for antimicrobial susceptibility testing of B. hyodysenteriae. The first steps toward standardization of the broth dilution procedure were made by Pringle et al (2006) and these recommendations are still used (Hidalgo et al 2009). …”

Section: Discussionmentioning

confidence: 99%

Antimicrobial susceptibility of Brachyspira hyodysenteriae isolated from 21 Polish farms

Żmudzki

Szczotka²,

Nowak³

et al. 2012

Polish Journal of Veterinary Sciences

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Swine dysentery (SD) is a common disease among pigs worldwide, which contributes to major production losses. Antimicrobial susceptibility testing of B. hyodysenteriae, the etiological agent of SD, is mainly performed by the agar dilution method. This method has certain limitations due to difficulties in interpretation of results. The aim of this study was the analysis of antimicrobial susceptibility of Brachyspira hyodysenteriae (B. hyodysenteriae) Polish field isolates by broth microdilution procedure. The study was performed on 21 isolates of B. hyodysenteriae, collected between January 2006 to December 2010 from cases of swine dysentery. VetMIC TM Brachyspira panels with antimicrobial agents (tiamulin, valnemulin, doxycycline, lincomycin, tylosin and ampicillin) were used for susceptibility testing of B. hyodysenteriae. The minimal inhibitory concentration (MIC) was determined by the broth dilution procedure. The lowest antimicrobial activity was demonstrated for tylosin and lincomycin, with inhibition of bacterial growth using concentrations >128 μg/ml and 32 μg/ml, respectively. In the case of doxycycline, the MIC values were ≤ 2.0 μg/ml. No decreased susceptibility to tiamulin was found among the Polish isolates and MIC values for this antibiotic did not exceed 1.0 μg/ml. The results of the present study confirmed that Polish B. hyodysenteriae isolates were susceptible to the main antibiotics (tiamulin and valnemulin) used in treatment of swine dysentery. Further studies are necessary to evaluate a possible slow decrease in susceptibility to tiamulin and valnemulin of B. hyodysenteriae strains in Poland.

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Quality-Control Ranges for Antimicrobial SusceptibilityTesting by Broth Dilution of the Brachyspira hyodysenteriae Type Strain (ATCC 27164^T)

Cited by 18 publications

References 3 publications

Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010

Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010

Isolation and characterization of Treponema phagedenis-like spirochetes from digital dermatitis lesions in Swedish dairy cattle

Antimicrobial susceptibility of Brachyspira hyodysenteriae isolated from 21 Polish farms

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Quality-Control Ranges for Antimicrobial SusceptibilityTesting by Broth Dilution of the Brachyspira hyodysenteriae Type Strain (ATCC 27164T)

Cited by 18 publications

References 3 publications

Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010

Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010

Isolation and characterization of Treponema phagedenis-like spirochetes from digital dermatitis lesions in Swedish dairy cattle

Antimicrobial susceptibility of Brachyspira hyodysenteriae isolated from 21 Polish farms

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Quality-Control Ranges for Antimicrobial SusceptibilityTesting by Broth Dilution of the Brachyspira hyodysenteriae Type Strain (ATCC 27164^T)