Decreased susceptibility to tiamulin and valnemulin among Czech isolates of Brachyspira hyodysenteriae.
The agar dilution method was used to investigate the sensitivity to pleuromutilins of 100 isolates of Brachyspira hyodysenteriae isolated from 63 pig farms between 1997 and 2001. In the period under investigation, MICs to both tiamulin and valnemulin increased, with differences between the periods 1997-98 and 1999-2001 being statistically significant (P < 0.001 for tiamulin and P < 0.0001 for valnemulin). Between 1997 and 2001, the MIC50 and MIC90 of tiamulin increased from 0.062 and 0.25 microg ml, respectively, to 1.0 and 4.0 microg ml. Valnemulin MIC50 and MIC90 were < or = 0.031 microg ml in 1997 and by 2001 were respectively, 2.0 and 8.0 microg ml. The increase in MICs of tiamulin and valnemulin demonstrated in this study reflect the intensity of pleuromutilin use in the treatment of swine dysentery in the Czech Republic.
Lobová
Dana
D
Institute of Microbiology and Immunology, Section of Pathobiology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Palackého 1-3, 612 42 Brno, Czech Republic.
Smola
Jiri
J
Institute of Microbiology and Immunology, Section of Pathobiology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Palackého 1-3, 612 42 Brno, Czech Republic.
Cizek
Alois
A
Institute of Microbiology and Immunology, Section of Pathobiology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Palackého 1-3, 612 42 Brno, Czech Republic.
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017401:Brachyspira hyodysenteriae / Q000187:drug effects*; D018153:Czech Republic; D004224:Diterpenes / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004403:Dysentery / Q000382:microbiology / Q000662:veterinary; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D013145:Spirochaetales Infections / Q000382:microbiology / Q000662:veterinary; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology
D000900:Anti-Bacterial Agents; D004224:Diterpenes; C117845:valnemulin; C014224:tiamulin