Maayan M C, Ofek I, Medalia O, Aronson M
Infect Immun. 1985 Sep;49(3):785-9. doi: 10.1128/iai.49.3.785-789.1985.
The infection rate (percentage of mice shedding 10(5) organisms per ml of urine) in 27 mice infected intravesicularly with a mannose-specific (MS+) phenotype of Klebsiella pneumoniae was 85% at day 7, and all the bacteria shed during the 7 days exhibited strong MS activity as estimated by a yeast aggregation assay. In contrast, the outcome of infection with an MS- phenotype of the same strain in 47 mice was heterogeneous: one group of 25 mice continued to shed the originally injected phenotype (MS-) throughout the investigation period, whereas the second group (22 mice) shed bacteria with various degrees of phenotypic conversion to MS+. In the first group, the rate of infection at day 7 was significantly reduced (28%) compared with that of the second group (68%). Mice infected with a mixture of 5% MS+ bacteria and 95% of an MS- variant which lost its ability to undergo phase variation had an infection rate of 89%, but at day 7 95% of the excreted bacteria were MS+. The infection rate of mice injected with the MS- variant was 14%, and none of the mice shed MS+ bacteria. The incidence of kidney pathology was higher in mice inoculated with the MS+ phenotype (3 of 10) or in the group in which the MS+ overgrew the MS- phenotype (4 of 10) as compared with the group of mice in which no such shift occurred (1 of 11). The kidneys of four mice which excreted mostly MS+ organisms harbored a population predominantly of the MS- phenotype. These results suggest that the MS adhesin confers an advantage in the initial steps of the infectious process in the bladder but not in later stages of infection in the kidney, emphasizing the importance of phase variation in the survival of bacteria at the various stages of the infectious process.
27只经膀胱内接种肺炎克雷伯菌甘露糖特异性（MS+）表型的小鼠，其感染率（每毫升尿液中排出10(5)个菌体的小鼠百分比）在第7天时为85%，并且在7天内排出的所有细菌通过酵母凝集试验评估均表现出强烈的MS活性。相比之下，47只接种同一菌株MS-表型的小鼠的感染结果则各不相同：一组25只小鼠在整个研究期间持续排出最初接种的表型（MS-），而第二组（22只小鼠）排出的细菌发生了不同程度的向MS+表型的转化。在第一组中，第7天时的感染率与第二组（68%）相比显著降低（28%）。接种5% MS+细菌和95%失去相变能力的MS-变体混合物的小鼠感染率为89%，但在第7天时，95%的排出细菌为MS+。接种MS-变体的小鼠感染率为14%，且没有小鼠排出MS+细菌。与未发生这种转变的小鼠组（11只中的1只）相比，接种MS+表型的小鼠（10只中的3只）或MS+表型占优势超过MS-表型的组（10只中的4只）中肾脏病理学发生率更高。4只主要排出MS+菌体的小鼠的肾脏中主要存在的是MS-表型的菌群。这些结果表明，MS黏附素在膀胱感染过程的初始阶段赋予优势，但在肾脏感染的后期阶段则不然，这强调了相变在细菌在感染过程各个阶段存活中的重要性。
