Gaines S A, Rollins L D, Silver R P, Washington M
Antimicrob Agents Chemother. 1978 Aug;14(2):252-6. doi: 10.1128/AAC.14.2.252.
Beagle dogs were fed a diet containing 0, 2, or 10 mug of dihydrostreptomycin (DSM) per g of feed. The 2-mug/g level was selected to represent a residue level of the antibiotic. In both treatment groups, medicated feed resulted in a shift from a predominantly streptomycin (SM)-susceptible coliform fecal population to an SM-resistant population. The proportion of resistant organisms was significant (P < 0.01) for both treatment groups. A definitive response did not occur with animals maintained on DSM-free diets. An increase in the prevalence of DSM-resistant organisms was observed after 15 days of DSM-supplemented feeding and persisted during the posttreatment phase of the study. The predominant pattern of resistance was SM-sulfamethoxypyridazine. Fifty-nine percent of SM-resistant strains transferred resistant determinants by conjugation to Escherichia coli K-12 recipients.
给比格犬喂食每克饲料含0、2或10微克二氢链霉素（DSM）的日粮。选择2微克/克的水平来代表抗生素的残留水平。在两个治疗组中，含药饲料导致粪便中以链霉素（SM）敏感的大肠菌群为主的菌群转变为对SM耐药的菌群。两个治疗组中耐药菌的比例均具有显著性（P<0.01）。在无DSM日粮饲养的动物中未出现明确反应。在补充DSM喂养15天后观察到DSM耐药菌的流行率增加，并在研究的治疗后阶段持续存在。主要的耐药模式是对SM-磺胺甲氧哒嗪耐药。59%的SM耐药菌株通过接合作用将耐药决定簇转移至大肠杆菌K-12受体菌。
