Barrow P A, Hassan J O, Berchieri A
AFRC Institute for Animal Health, Houghton Laboratory, Huntingdon, Cambridgeshire.
Epidemiol Infect. 1990 Jun;104(3):413-26. doi: 10.1017/s0950268800047439.
Chickens given orally at 4 days of age a smooth spectinomycin resistant mutant (Spcr) of Salmonella typhimurium strain F98 excreted the organism in their faeces for approximately 4 weeks. Following oral administration of a nalidixic acid resistant (Nalr) mutant of the same strain 4 weeks later when the chickens had virtually cleared themselves of the first infection, these chickens excreted far fewer salmonella organisms and for a shorter time than did a previously uninfected control group of chickens which were infected at the same time with the Nalr mutant. Chickens inoculated intramuscularly at 4 days developed a similar immunity to challenge and also excreted the immunizing strain in their faeces. In contrast intramuscular inoculation or incorporation into the food of formalin-killed S. typhimurium organisms had little lasting effect on the faecal excretion of the challenge strain. Two attenuated mutants of strain F98 Nalr were produced: one was a rough strain produced by lytic bacteriophage and the other was an aro A auxotrophic mutant which had been cured of the 85 kilobase-pair virulence-associated plasmid. These mutants were avirulent for chickens, mice, calves and man and when ingested by human volunteers did not persist in the faeces. When inoculated intramuscularly into chickens they produced an early reduction in faecal excretion of the challenge strain (Spcr) which was not maintained. Oral administration of both strains produced reductions in faecal excretion of the challenge strain. This was much more noticeable with the rough strain which was itself excreted for a much longer period than the parent strain.
4日龄雏鸡口服鼠伤寒沙门氏菌F98株的光滑型壮观霉素抗性突变体（Spcr）后，在粪便中排出该菌约4周。4周后，当雏鸡基本清除了首次感染时，口服同一菌株的萘啶酸抗性（Nalr）突变体，与同时感染Nalr突变体的未感染对照组雏鸡相比，这些雏鸡排出的沙门氏菌数量少得多，且排出时间较短。4日龄时肌肉注射接种的雏鸡对攻毒产生了类似的免疫力，并且也在粪便中排出免疫菌株。相比之下，肌肉注射接种或在食物中添加福尔马林灭活的鼠伤寒沙门氏菌对攻毒株的粪便排出几乎没有持久影响。产生了F98 Nalr菌株的两个减毒突变体：一个是由裂解噬菌体产生的粗糙菌株，另一个是已消除85千碱基对毒力相关质粒的aro A营养缺陷型突变体。这些突变体对雏鸡、小鼠、小牛和人类无毒，人类志愿者摄入后不会在粪便中持续存在。肌肉注射接种到雏鸡体内时，它们使攻毒株（Spcr）的粪便排出量早期减少，但这种减少没有持续。口服这两种菌株都使攻毒株的粪便排出量减少。粗糙菌株的这种情况更明显，其本身在粪便中的排出时间比亲本菌株长得多。
