PROPERTIES OF HIGH AND LOW-DENSITY SUBPOPULATIONS OF GROUP-B STREPTOCOCCI - ENHANCED VIRULENCE OF THE LOW-DENSITY VARIANT
PROPERTIES OF HIGH AND LOW-DENSITY SUBPOPULATIONS OF GROUP-B STREPTOCOCCI - ENHANCED VIRULENCE OF THE LOW-DENSITY VARIANT
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DOI：
10.1016/0882-4010(88)90035-6
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发表时间：
1988-11-01
影响因子：
3.8
通讯作者：
WAGNER, M
中科院分区：
文献类型：
--
作者：
HAKANSSON, S;BERGHOLM, AM;WAGNER, M
从组B链球菌（GBS）参考菌株090 la Colindale的两个亚群，这两个亚群的类型特异性多糖的生物合成的能力显着不同，通过在低渗Percoll密度梯度分离。在原始菌株和高，低密度的变种，有浮力密度和生物合成的类型特异性多糖的超微结构和定量测定测定之间呈负相关。通过皮下植入组织笼感染家兔，研究这些变体的侵袭性。在感染高度包囊化细菌的动物中，在感染后8 h检测到重度菌血症，而在接受高密度细菌和少量包囊的动物中，直到5天后才检测到重度菌血症。从这些家兔的血液或器官中回收的所有分离株均为富荚膜表型，表明高密度细菌亚群的表型转变。一个明显类似的表型转变，注意到在分离的婴儿与早发性败血症。与从母亲宫颈分离的细菌定殖群体相比，从婴儿获得的分离物中低密度细菌占主导地位。从这些III型菌株，亚群具有不同的密度最大值。在这些亚群的体外传代过程中，观察到了向少囊化、高密度细菌占优势的反向转变。
From the group B streptococcus (GBS) reference strain 090 la Colindale two subpopulations, which differed markedly regarding their capacities for biosynthesis of type-specific polysaccharide, were obtained by separation on a hypotonic Percoll density gradient. In the original strain and the high and low density variants, there was a negative correlation between buoyant density and bio-synthesis of type-specific polysaccharide as determined by ultrastructure and quantitative assays. The invasiveness of these variants was investigated by infecting rabbits via subcutaneously implanted tissue cages. In the animals infected with highly encapsulated bacteria, heavy bacteremia was detected 8 h post-infection, whereas in the animals which received high density bacteria with small amount of capsule, heavy bacteremia was not detected until after five days. All isolates recovered from the blood or organs of these rabbits were of the capsule rich phenotype, indicating a phenotypic shift in the subpopulation of high density bacteria. An apparently similar phenotypic shift was noted in an isolate from a baby with early onset septicemia. There was a dominance of low density bacteria in the isolate obtained from the baby as compared with the colonizing population of bacteria isolated from the cervix of the mother. From these type III isolates, subpopulations with different density maxima were obtained. A reversed shifting towards dominance of less encapsulated, high density bacteria was observed during in vitro passage of these subpopulations.