Mmolawa Princess T, Willmore Rina, Thomas Connor J, Heuzenroeder Michael W
Infectious Diseases Laboratories, Institute of Medical and Veterinary Science, Adelaide, South Australia, Australia.
Int J Med Microbiol. 2002 Mar;291(8):633-44. doi: 10.1078/1438-4221-00178.
Salmonella enterica serovar Typhimurium is the most common Salmonella serovar isolated from humans in Australia. The most common definitive phage types (DT) include 9, 64 and 135. Induction of lysogenic phages from DT 64 with mitomycin C followed by cesium chloride gradient purification, resulted in separation of two populations of phage particles. DNA extracted from these particles that was digested with SmaI showed two distinct patterns of banding. Transmission electron microscopy showed that both phage particles belong to the podovirus family of the C1 morphotype. One of the phages, ST64T is capable of mediating both generalized transduction and bacteriophage type conversion. Crude phage lysate induced from S. Typhimurium DT 64 was capable of phage type conversion. S. Typhimurium DT 9 was converted to DT 64 and DT 135 was converted to DT 16. S. Typhimurium DT 41 was also converted to DT 29. Amplified-fragment length polymorphism revealed differences between the original isolates and the convertants. Phage type conversion raises the question of the stability of the bacterial phage types in natural settings and the possibility of its occurrence during an outbreak scenario.
肠炎沙门氏菌鼠伤寒血清型是在澳大利亚从人类分离出的最常见的沙门氏菌血清型。最常见的定型噬菌体类型（DT）包括9、64和135。用丝裂霉素C诱导DT 64的溶原性噬菌体，然后通过氯化铯梯度纯化，导致两种噬菌体颗粒群体分离。从这些颗粒中提取的DNA用SmaI消化后显示出两种不同的条带模式。透射电子显微镜显示，两种噬菌体颗粒均属于C1形态型的短尾病毒科。其中一种噬菌体ST64T能够介导普遍性转导和噬菌体类型转换。从鼠伤寒沙门氏菌DT 64诱导的粗噬菌体裂解物能够进行噬菌体类型转换。鼠伤寒沙门氏菌DT 9被转换为DT 64，DT 135被转换为DT 16。鼠伤寒沙门氏菌DT 41也被转换为DT 29。扩增片段长度多态性揭示了原始分离株和转化株之间的差异。噬菌体类型转换引发了自然环境中细菌噬菌体类型稳定性的问题以及在暴发情况下其发生的可能性。
