Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA.
Infect Immun. 2012 Dec;80(12):4186-94. doi: 10.1128/IAI.00684-12. Epub 2012 Sep 17.
Urinary tract infection (UTI) is most often caused by uropathogenic Escherichia coli (UPEC). UPEC inoculation into the female urinary tract (UT) can occur through physical activities that expose the UT to an inherently polymicrobial periurethral, vaginal, or gastrointestinal flora. We report that a common urogenital inhabitant and opportunistic pathogen, group B Streptococcus (GBS), when present at the time of UPEC exposure, undergoes rapid UPEC-dependent exclusion from the murine urinary tract, yet it influences acute UPEC-host interactions and alters host susceptibility to persistent outcomes of bladder and kidney infection. GBS presence results in increased UPEC titers in the bladder lumen during acute infection and reduced inflammatory responses of murine macrophages to live UPEC or purified lipopolysaccharide (LPS), phenotypes that require GBS mimicry of host sialic acid residues. Taken together, these studies suggest that despite low titers, the presence of GBS at the time of polymicrobial UT exposure may be an overlooked risk factor for chronic pyelonephritis and recurrent UTI in susceptible groups, even if it is outcompeted and thus absent by the time of diagnosis.
尿路感染（UTI）通常是由尿路致病性大肠杆菌（UPEC）引起的。UPEC 可通过使 UT 暴露于固有多微生物的尿道周围、阴道或胃肠道菌群中的物理活动而接种到女性 UT 中。我们报告称，一种常见的泌尿生殖道寄居菌和机会性病原体 B 组链球菌（GBS），当存在于 UPEC 暴露时，会迅速被 UPEC 依赖排除出小鼠的泌尿道，但它会影响急性 UPEC-宿主相互作用，并改变宿主对膀胱和肾脏感染持续结局的易感性。GBS 的存在导致急性感染期间膀胱腔中 UPEC 滴度增加，并且对活 UPEC 或纯化脂多糖（LPS）的小鼠巨噬细胞炎症反应减少，这些表型需要 GBS 模拟宿主唾液酸残基。总之，这些研究表明，尽管 GBS 滴度较低，但在多微生物 UT 暴露时存在 GBS 可能是易患人群慢性肾盂肾炎和复发性 UTI 的一个被忽视的危险因素，即使它在诊断时被竞争并因此不存在。
