Cooper G L, Venables L M, Nicholas R A, Cullen G A, Hormaeche C E
Poultry Department, Central Veterinary Laboratory, Weybridge, Surrey, UK.
Vaccine. 1992;10(4):247-54. doi: 10.1016/0264-410x(92)90160-l.
Two strains of Salmonella enteritidis phage type 4 isolated from chickens, SeLA5 and Se267, were virulent in Balb/c mice by intraperitoneal (i.p.) infection. In 18-20-day-old chickens given 10(7) c.f.u. intravenously (i.v.), both strains caused some deaths. One-day-old chicks infected orally with 10(9) c.f.u. of either strain also suffered limited mortality. Strain SeLA5 was the more virulent by the oral route. AroA mutants SeLA5 aroA and Se267 aroA were reduced in i.p. virulence by up to six logs in the Balb/c mouse model, did not kill 18-20-day-old chickens when injected i.v. and did not multiply in the tissues. Oral vaccination of chicks with either 10(9) c.f.u. at one-day-old or 10(5) c.f.u. at seven-day intervals until day 21 with vaccine strains SeLA5 aroA or Se267 aroA conferred significant protection against intravenous challenge with virulent strain Se109 NalR and reduced intestinal shedding following oral challenge. Seroconversion following oral vaccination was not seen with the lower dose regimen and was low with the higher dose. Seroconversion following oral challenge was marked in unvaccinated birds but much lower in vaccinated birds, suggesting that oral vaccination had prevented invasion by the challenge strain.
从鸡中分离出的两株4型肠炎沙门氏菌噬菌体，即SeLA5和Se267，经腹腔注射感染Balb/c小鼠后具有致病性。给18至20日龄的鸡静脉注射10⁷cfu，这两株菌均导致了一些死亡。用10⁹cfu的任一菌株经口感染1日龄雏鸡，也有一定程度的死亡。SeLA5菌株经口途径的致病性更强。AroA突变体SeLA5 aroA和Se267 aroA在Balb/c小鼠模型中腹腔致病性降低了多达6个对数级，静脉注射时不会导致18至20日龄的鸡死亡，且在组织中不会增殖。用疫苗菌株SeLA5 aroA或Se267 aroA在1日龄时给雏鸡口服10⁹cfu，或在第21天前每隔7天口服10⁵cfu，可显著保护雏鸡免受强毒株Se109 NalR的静脉攻击，并减少口服攻击后的肠道排菌。较低剂量方案口服疫苗后未出现血清转化，较高剂量时血清转化率较低。未接种疫苗的鸡口服攻击后血清转化明显，但接种疫苗的鸡血清转化低得多，这表明口服疫苗可防止攻击菌株的侵袭。
