In Vitro Susceptibility of 21 Antimicrobial Agents to 37 Isolates of Brachyspira hyodysenteriae Isolated from Pigs in Okinawa Prefecture

Abstract

ABSTRACT. The in vitro susceptibilities to 21 antimicrobial agents, of 37 isolates of Brachyspira (B.) hyodysenteriae isolated from pigs in Okinawa meat center and a pig farm in Okinawa Prefecture, Japan, were determined by the agar dilution method. Carbadox was the most active of all the agents tested against the isolates (MIC: <0.003 to 0.05). All the isolates were highly susceptible to olaquindox, tiamulin, dimetridazole, efrotomycin and valnemulin with MICs ranging from ≤0.1 to 1.6 µg/ml. Penicillins, chloramphenicol, tetracyclines, terdecamycin and streptomycin were also active against the isolates. Most isolates were resistant to lincomycin, avilamycin and macrolides (with the exception of terdecamycin). KEY WORDS: antimicrobial agent, Brachyspira hyodysenteriae, minimum inhibitory concentration.

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.…”

In Vitro Antimicrobial Susceptibility of Brachyspira hyodysenteriae Strains Isolated in Japan from 1985 to 2009

“…Among the other 19 antibiotics accepted as feed additive antibiotics to promote the growth of pigs with potential antibacterial effects, efrotomycin, Nmethylhydroxypyridone glycoside antibiotic with activity primarily against gram-positive bacteria [6] and exclusively used in veterinary practice, is reported to have low minimum inhibitory concentration (MIC) values ranging from 0.1 to 0.8 g/ml against B. hyodysenteriae [15].…”

Effects of Griseoviridin and Viridogrisein against Swine Dysentery in Experimental Infection by Using Mice and Pigs

“…For example, the MIC values of penicillin G (penicillin group), furazolidone (nitrofuran group), and monensin (polyether group) obtained in in vitro studies are less than 1.0 (µg/ml) [7,15]; however, none of them are expected to have a preventive or therapeutic effect against swine dysentery. The MIC value for lincomycin is 25-100 µg/ml and is marketed as having excellent preventive and therapeutic effects against swine dysentery.…”

“…Thus far, a variety of chemotherapeutic drugs and antibiotics have been developed for the prevention and treatment of swine dysentery. Carbadox has been used as a synthetic antimicrobial agent, and tiamulin, sedecamycin, lincomycin, and efrotomycin have been used as antibiotics; however, the appearance of resistant bacteria has become an issue of concern [5,8,15].…”