Tiamulin provides excellent activity in vitro against the primary pathogen, B. hyo., and is also highly effective against the anaerobes (Fusobacterium spp and Bacteroides spp) which act as secondary invaders. [?]
In addition tiamulin is effective against B. hyo, which have become resistant to carbadox, lincomycin, and tylosin. Studies which confirm this have been reported, among others, from Poland [?], Sweden [?], [?], UK/Denmark/Sweden [?] and Australia [?]. See Tables below.
Cases of non-complicated swine dysentery in the field, which are clinically refractory to Denagard, are rare.
| POLAND |
Jakubowski, T. (1996) |
| Range of MIC values (µg/ml) of three antimicrobials against isolated field strains of B. hyodysenteriae |
| Antimicrobial |
3 field strains
pre-1993 |
7 field strains
1993 |
4 field strains
1994 |
10 field strains
1995 |
| Virginiamycin |
10- >60 |
20-60 |
30-60 |
20-100 |
| Lincomycin |
10-130 |
90-150 |
80-150 |
80-150 |
| Denagard® (tiamulin) |
0.85-2.5 |
0.5-2.5 |
1.5-3.0 |
0.1-2.5 |
|
| SWEDEN |
Fellström, C. (1996) |
| Comparison of MIC50 values (µg/ml) for field strains of B. hyodysenteriae isolated in 1988-90 and 1990-94 |
| Antimicrobial |
1988-90
n=67) |
1990-94
(n=24) |
| Tylosin |
8.0 |
16.0 |
| Denagard® (tiamulin) |
0.06 |
0.06 |
|
| UK/DENMARK/SWEDEN |
Karlsson, M. and others (2001) |
| MIC50, MIC90 and ranges of MIC’s (µg/ml) for Denagard® (tiamulin) against B. hyo in different studies |
| Study |
Year |
No. of
isolates |
MIC range |
MIC50 |
MIC90 |
| UK, Aitken and others |
1999 |
10 |
0.025-1 |
0.3 |
1 |
| Denmark, Møller and others |
1996 |
10 |
0.125-1 |
0.125 |
1 |
| Sweden, Karlsson and others |
2001 |
50 |
0.031-2 |
0.125 |
0.125 |
|
| AUSTRALIA |
Karlsson, M. and others (2001) |
| In vitro sensitivity (µg/ml) for B. hyo isolates from Australia isolated in 1986-89, 1990-1994 and 1995-99 |
| Antimicrobial |
1986-89 |
1990-94 |
1995-99 |
| Tylosin |
MIC50 >256 |
256 |
>256 |
| |
MIC90 >256 |
>256 |
>256 |
| Lincomycin |
MIC50 32 |
8 |
8 |
| |
MIC90 32 |
64 |
64 |
| Denagard® (tiamulin) |
MIC50 0.125 |
0.063 |
0.125 |
| |
MIC90 0.25 |
0.5 |
1.0 |
|
| SWEDEN |
Karlsson, M. and others (2004) |
| Antimicrobial susceptibility for 20 Swedish field isolates of B. hyo and the B. hyo-type strain B78T (ATCC 27, 64T) to tiamulin and Aivlosin |
| Isolates |
Denagard® (tiamulin) |
Aivlosin |
| S1 |
0.031 |
1 |
| S2 |
0.125 |
1 |
| S3 |
0.125 |
4 |
| S4 |
0.063 |
4 |
| S5 |
0.031 |
2 |
| S6 |
0.125 |
2 |
| S7 |
0.125 |
16 |
| S8 |
0.063 |
8 |
| S9 |
0.063 |
4 |
| S10 |
0.063 |
8 |
| S11 |
0.25 |
8 |
| S12 |
0.5 |
16 |
| S13 |
0.25 |
8 |
| S14 |
0.063 |
8 |
| S15 |
0.25 |
8 |
| S16 |
0.125 |
1 |
| S17 |
0.063 |
1 |
| S18 |
0.125 |
1 |
| S19 |
0.031 |
2 |
| S20 |
0.125 |
16 |
| Mean |
0.129 |
5.95 |
| B78T |
0.063 |
2 |
|
| 
