Mathew A G, Garner K N, Ebner P D, Saxton A M, Clift R E, Liamthong S
Department of Animal Science, University of Tennessee, 2505 River Drive, Knoxville, TN 37996, USA.
Foodborne Pathog Dis. 2005 Fall;2(3):212-20. doi: 10.1089/fpd.2005.2.212.
To determine effects of exposure of parental animals to antibiotics on antibiotic resistance in bacteria of offspring, sows were either treated or not treated with oxytetracycline prior to farrowing and their pigs were challenged with Salmonella enterica Typhimurium and treated or not treated with oxytetracycline and apramycin. Fecal Escherichia coli were obtained from sows, and E. coli and salmonella were recovered from pigs. Antibiotic resistance patterns of isolates were determined using a minimum inhibitory concentration (MIC) analysis. Polymerase chain reaction (PCR) and electroporation were used to characterize the genetic basis for the resistance and to determine the location of resistance genes. Treatments had little effect on resistance of the salmonella challenge organism. The greatest resistance to apramycin occurred in E. coli from pigs treated with apramycin and whose sows had earlier exposure to oxytetracycline. Resistance to oxytetracycline was consistently high throughout the study in isolates from all pigs and sows; however, greater resistance was noted in pigs nursing sows that had previous exposure to that drug. The aac(3)-IV gene, responsible for apramycin resistance, was found in approximately 90% of apramycin-resistant isolates and its location was determined to be on plasmids. Several resistant E. coli bio-types were found to contain the resistance gene. These results indicate that resistance to apramycin and oxytetracycline in E. coli of pigs is affected by previous use of oxytetracycline in sows.
为了确定亲代动物接触抗生素对后代细菌抗生素耐药性的影响，在分娩前，对母猪分别用土霉素进行处理或不处理，然后用鼠伤寒沙门氏菌对它们的仔猪进行攻毒，并分别用土霉素和阿普拉霉素进行处理或不处理。从母猪获取粪便大肠杆菌，从仔猪分离大肠杆菌和沙门氏菌。使用最低抑菌浓度（MIC）分析确定分离株的抗生素耐药模式。采用聚合酶链反应（PCR）和电穿孔技术来表征耐药性的遗传基础并确定耐药基因的位置。处理对沙门氏菌攻毒菌株的耐药性影响不大。在用阿普拉霉素处理且其母猪较早接触过土霉素的仔猪的大肠杆菌中，对阿普拉霉素的耐药性最强。在整个研究过程中，所有仔猪和母猪分离株对土霉素的耐药性一直很高；然而，在哺乳过先前接触过该药物的母猪的仔猪中，耐药性更强。在约90%的阿普拉霉素耐药分离株中发现了负责阿普拉霉素耐药性的aac(3)-IV基因，其位置确定在质粒上。发现几种耐药大肠杆菌生物型含有该耐药基因。这些结果表明，仔猪大肠杆菌对阿普拉霉素和土霉素的耐药性受母猪先前使用土霉素的影响。
