Chart H, Row B, Threlfall E J, Ward L R
Division of Enteric Pathogens, Central Public Health Laboratory, London, U.K.
FEMS Microbiol Lett. 1989 Jul 1;51(1):37-40. doi: 10.1016/0378-1097(89)90073-6.
Three strains of Salmonella enteritidis phage type 4 (PT4) and 33 strains of S. enteritidis phage type 7 (PT7) were examined for the ability to produce lipopolysaccharide (LPS) and for plasmid carriage. The LPS of all strains of PT4 gave a typical 'ladder' pattern by SDS-PAGE and silver staining, and on serotyping these strains were shown to express the O-antigens 9, 12. In contrast, strains of PT7 did not express long-chain LPS and were autoagglutinable. All strains of PT4 and the majority of strains of PT7 carried a single plasmid of 38 MDa, indistinguishable when characterised by restriction endonuclease fragmentation analysis. Epidemiological and experimental observations have demonstrated a relationship between strains of S. enteritidis PT4 and PT7, and our results, using mice, show that the loss of ability of strains of PT4 to snythesise LPS is responsible for the conversion of highly virulent strains of PT4 to avirulent strains of PT7. From epidemiological data of human infections in England and Wales, we suggest that strains of S. enteritidis PT7 may be less virulent for humans.
对3株肠炎沙门氏菌4型（PT4）菌株和33株肠炎沙门氏菌7型（PT7）菌株进行了产脂多糖（LPS）能力及质粒携带情况的检测。所有PT4菌株的LPS经SDS-PAGE和银染呈现典型的“阶梯”模式，血清分型显示这些菌株表达O抗原9、12。相比之下，PT7菌株不表达长链LPS且具有自凝性。所有PT4菌株及大多数PT7菌株携带一个38 MDa的质粒，经限制性内切酶片段分析鉴定时无法区分。流行病学和实验观察已证明肠炎沙门氏菌PT4和PT7菌株之间存在关联，我们用小鼠进行的研究结果表明，PT4菌株合成LPS能力的丧失导致了高毒力的PT4菌株转变为无毒力的PT7菌株。根据英格兰和威尔士人类感染的流行病学数据，我们认为肠炎沙门氏菌PT7菌株对人类的毒力可能较低。
