Hinton M, Al-Chalaby Z A, Allen V, Linton A H
J Hyg (Lond). 1982 Oct;89(2):269-78. doi: 10.1017/s0022172400070807.
Antibacterial drugs (oxytetracycline, streptomycin and sulphonamides) were included in the drinking water of healthy broiler chicks from the sixth to the twentieth day of life to select a resistant gut flora. On the twenty-first day the birds were divided into three groups and reared in separate rooms until 100 days of age. One group was housed in cages with wire floors while the others were reared on litter. Faeces from adult hens were added regularly to the litter of one of these groups to determine its effect on the gut flora of the chicks. The ecology of Escherichia coli was studied using O-serotyping, biotyping and antibacterial drug resistogram typing. The proportion of E. coli in the dominant faecal flora resistant to two to four antibacterial drugs increased with time to reach a peak several days after the drugs were withdrawn. Thereafter, the level of drug resistance in the E. coli declined equally in all three groups. The majority of organisms with multiple resistance were derived from biotypes of O-serotypes initially resistant to only one drug and were identified before the drugs were administered. The decline in the level of resistance in the dominant faecal flora after the fourth week was due to the appearance of either new O-serotypes or new biotypes of O-serotypes previously shown to be multiply resistant, and which were either sensitive or resistant to only one drug. It is probably that these new strains were derived from the food since several O-serotypes appeared simultaneously in all three groups of birds.
在健康肉仔鸡出生后的第6天至第20天，在其饮用水中添加抗菌药物（土霉素、链霉素和磺胺类药物），以筛选出具有耐药性的肠道菌群。在第21天，将这些鸡分为三组，分别饲养在不同的房间直至100日龄。一组饲养在带金属网地板的笼子里，而其他两组则饲养在垫料上。定期向其中一组的垫料中添加成年母鸡的粪便，以确定其对雏鸡肠道菌群的影响。利用O血清型分型、生物分型和抗菌药物耐药谱分型研究了大肠杆菌的生态学。对两到四种抗菌药物耐药的大肠杆菌在优势粪便菌群中的比例随时间增加，在停药几天后达到峰值。此后，三组中大肠杆菌的耐药水平均同等下降。大多数多重耐药菌来自最初仅对一种药物耐药的O血清型生物型，且在给药前就已鉴定出来。第四周后优势粪便菌群耐药水平的下降是由于出现了新的O血清型或之前显示为多重耐药的O血清型的新生物型，这些新生物型对一种药物敏感或耐药。这些新菌株可能来自食物，因为在所有三组鸡中同时出现了几种O血清型。
