Sensitivity of strains of Serpulina hyodysenteriae isolated in Hungary to chemotherapeutic drugs

Abstract

The sensitivity of 332 strains of Serpulina hyodysenteriae isolated in Hungary between 1978 and 1992 was tested against seven chemotherapeutic drugs frequently used for the treatment of swine dysentery, and the changes in the patterns of resistance were also monitored. All the strains remained sensitive to carbadox, with minimum inhibitory concentrations (MIC) of only 0.05 to 0.40 microgram/ml at present. The susceptibility of the strains to dimetridazole has gradually decreased, but about half of the strains are still sensitive, with large numbers of "moderately sensitive' strains; the MIC values varied within wide limits (0.1 to 50 micrograms/ml). Most of the strains were resistant to tylosin, with MIC values from 0.1 to 100 micrograms/ml. The number of strains resistant to lincomycin has gradually increased, but about half of the strains remain sensitive; the MIC values ranged from 0.2 to 100 micrograms/ml. Recently, tiamulin has proved the most effective antibiotic, but some resistant strains have already emerged (MIC values 0.05 to 50 micrograms/ml). Monensin was good for the prevention of swine dysentery, but resistance may evolve quickly; the MIC values ranged from 0.4 to 25 micrograms/ml. For sedecamycin, the MIC values (6.25 to 100 micrograms/ml) were much higher than expected.

Antimicrobial susceptibility of Brachyspira hyodysenteriae isolated from 21 Polish farms

“…This is in agreement with previous findings confirming universal, worldwide resistance of B. hyodysenteriae isolates to tylosin (Binek et al 1994, Molnar 1996, Gresham et al 1998, Fossi et al 1999, Kärlsson et al 2001, 2003, Rohde et al 2004, Uezato et al 2004, Hidalgo et al 2009). It is known that the point mutation that causes tylosin resistance at position 2058 in the 23S rRNA gene is also known to increase the MICs for the lincosamide antibiotics (Kärlsson et al 1999), and this also may help to explain the trend for the increased MICs to lincomycin that was found in our study.…”

“…Such a situation was recorded in the United Kingdom (Gresham et al 1998), Hungary (Molnar 1996), Sweden (Kärlsson et al 2003), Finland (Fossi et al 1999) and Spain (Hidalgo et al 2009), Japan (Uezato et al 2004) and Australia (Kärlsson et al 2002). Although B. hyodysenteriae isolates tested in Poland were susceptible to tiamulin, a tendency for decreasing susceptibility was identified.…”

Further characterization of porcine Brachyspira hyodysenteriae isolates with decreased susceptibility to tiamulin

“…In many countries, tiamulin, a pleuromutilin, is the drug of choice for treatment of swine dysentery. However, isolates of B. hyodysenteriae with decreased susceptibility to tiamulin have been reported (Cizek et al, 2002;Gresham et al, 1998;Karlsson et al, 2002;Molnar, 1996). The mechanism of tiamulin resistance in B. hyodysenteriae is not known; hence, it is not known whether spread of isolates with decreased susceptibility is clonal or if the resistance trait is transferable between clones.…”

Antibiotic use in animal feed and its impact on human healt

“…Quinoxalones are effective in controlling swine dysentery (Molnar, 1996; Commission on Antimicrobial Feed Additives, 1997), but resistance appears to emerge with tylosin, lincomycin, monensin and tiamulin (Molnar, 1996). Porcine proliferative enteropathy can be effectively prevented by tylosin or tiamulin (McOrist et al 1996 or a range of other growth promoters including salinomycin and spiramycin (Tsinas et al 1998).…”