identification of an unusual pattern of global gene expression in group b streptococcus grown in human blood一场不同寻常的全球基因表达模式的识别在人类血液b群链球菌生长.pdfVIP

Identification of an Unusual Pattern of Global Gene Expression in Group B Streptococcus Grown in Human Blood 1,2,3 1 1 1 Laurent Mereghetti , Izabela Sitkiewicz , Nicole M. Green , James M. Musser * 1 Center for Molecular and Translational Human Infectious Diseases Research, The Methodist Hospital Research Institute, Houston, Texas, United States of America, ´ ´ 2 Universite Franc¸ois Rabelais de Tours, IFR136, EA3854 ‘‘Bacteries et risque materno-foetal’’, Tours, France, 3 CHU de Tours, Tours, France Abstract Because passage of the bacterium to blood is a crucial step in the pathogenesis of many group B Streptococcus (GBS) invasive infections, we recently conducted a whole-genome transcriptome analysis during GBS incubation ex vivo with human blood. In the current work, we sought to analyze in detail the difference in GBS gene expression that occurred in one blood sample (donor A) relative to other blood samples. We incubated GBS strain NEM316 with fresh heparinized human blood obtained from healthy volunteers, and analyzed GBS genome expression and cytokine production. Principal component analysis identified extensive clustering of the transcriptome data among all samples at time 0. In striking contrast, the whole bacterial gene expression in the donor A blood sample was significantly different from the gene expression in all other blood samples studied, both after 30 and 90 min of incubation. More genes were up-regulated in donor A blood relative to the other samples, at 30 min and 90 min. Furthermore, there was significant variation in transcript levels between donor A blood