Effect of racephenicol on antibiotic resistance of lactose-fermenting enteric bacteria in chickens.
The incidence of lactose-fermenting enteric organisms resistant to chloramphenicol increased from less than 0.1% prior to treatment to more than 90% in two groups of chickens fed racephenicol-supplemented feed at 50 or 140 g/ton for 10 days, whereas controls remained unchanged. A concurrent increase in the incidence of organisms resistant to dihydrostreptomycin, oxytetracycline, ampicillin, and sulfonamides also occurred. Minimum inhibitory concentrations for chloramphenicol increased from <10 mug/ml to >300 mug/ml in most Escherichia coli isolates in response to treatment. The observed resistance was transferable to E. coli and Salmonella.
D000081:Acetamides / Q000494:pharmacology; D000821:Animal Feed; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002645:Chickens; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D005285:Fermentation; D005503:Food Additives / Q000494:pharmacology; D007785:Lactose / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D010627:Phenethylamines / Q000494:pharmacology*; D012475:Salmonella / Q000187:drug effects / Q000378:metabolism; D013450:Sulfones / Q000494:pharmacology*
D000081:Acetamides; D000900:Anti-Bacterial Agents; D005503:Food Additives; D010627:Phenethylamines; D013450:Sulfones; D007785:Lactose