In vitro antimicrobial activity against 10 North American and European Lawsonia intracellularis isolates

Antimicrobial Susceptibility Testing of Two Lawsonia intracellularis Isolates Associated with Proliferative Hemorrhagic Enteropathy and Porcine Intestinal Adenomatosis in South Korea

“…Reports regarding this organism involve low numbers of isolates from Europe and/or North America (12,17). Thus, McOrist et al included only three isolates of L. intracellularis in a European study (12), and Wattanaphansak et al tested six isolates from North America and four from Europe in a U.S. study (17). The present study represents the first antimicrobial susceptibility testing of L. intracellularis isolates from Asia.…”

“…A wide range of antimicrobials has been recommended for the treatment of pigs with L. intracellularis infection in Asia, but the recommendations have not been based on susceptibility testing in vitro. Therefore, this preliminary study gives the first insight into the relationship of in vitro antibiotic activity and clinical effectiveness reports in South Korea and, taken together with previously published data (12,17), should be used only as a guide to determine which antimicrobials could be effective in reducing or treating L. intracellularis infection and disease. Further in vivo studies are needed to confirm the antimicrobial efficacies against Asian isolates of L. intracellularis.…”

“…In vitro studies of the antimicrobial susceptibility of this obligate intracellular bacterium necessitate complicated cell culture systems (3,5,6,12), and only a few laboratories in the world perform antimicrobial susceptibility testing, because few L. intracellularis strains have been successfully isolated and maintained in culture (17). Thus, while knowledge of the antimicrobial susceptibility of L. intracellularis is important for management and treatment decisions, published data on its in vitro antimicrobial sensitivity are very limited.…”

“…The concentrations of the L. intracellularis inocula were between 5.9 ϫ 10 5 and 7.1 ϫ 10 6 bacteria/ml. The MICs of each antimicrobial against L. intracellularis were determined using antimicrobial susceptibility testing and data analysis methodology as previously described (17).…”

“…Data on in vitro antimicrobial susceptibility for L. intracellularis are very limited, because the difficulty of maintaining and culturing L. intracellularis has resulted in a limited number of available strains. Reports regarding this organism involve low numbers of isolates from Europe and/or North America (12,17). Thus, McOrist et al included only three isolates of L. intracellularis in a European study (12), and Wattanaphansak et al tested six isolates from North America and four from Europe in a U.S. study (17).…”