Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
Graduate Program in Genetics, University of Iowa, Iowa City, Iowa, USA.
J Bacteriol. 2023 Oct 26;205(10):e0016423. doi: 10.1128/jb.00164-23. Epub 2023 Jul 13.
is a Gram-positive opportunistic pathogen that results in 220,000 infections, 12,000 deaths, and upwards of $1 billion in medical costs in the United States each year. is highly resistant to a variety of antibiotics, but we have a poor understanding of how senses and responds to antibiotic stress and how such sensory systems affect clinical outcomes. We have identified a spontaneous mutant that displays increased daptomycin resistance. We performed whole-genome sequencing and found a nonsense mutation, S605*, in , which encodes a putative sensor histidine kinase of a two-component system (TCS). The * mutant has an ~4- to 8-fold increase in the daptomycin MIC compared to the wild type (WT). We found that the expression of constitutively active DraR in the WT increases daptomycin resistance 8- to 16-fold and increases bacitracin resistance ~4-fold. We found that a selection of lipid II-inhibiting compounds leads to the increased activity of the luciferase-based reporter P, including vancomycin, bacitracin, ramoplanin, and daptomycin. Using RNA sequencing (RNA-seq), we identified the DraRS regulon. Interestingly, we found that DraRS can induce the expression of the previously identified locus required for the synthesis of a novel glycolipid produced in . Our data suggest that the induction of the locus by DraR explains some, but not all, of the DraR-induced daptomycin and bacitracin resistance. is a major cause of hospital-acquired diarrhea and represents an urgent concern due to the prevalence of antibiotic resistance and the rate of recurrent infections. encodes ~50 annotated two-component systems (TCSs); however, only a few have been studied. The function of these unstudied TCSs is not known. Here, we show that the TCS DraRS plays a role in responding to a subset of lipid II-inhibiting antibiotics and mediates resistance to daptomycin and bacitracin in part by inducing the expression of the recently identified locus, which encodes enzymes required for the production of a novel glycolipid in .
是一种革兰氏阳性机会性病原体，每年导致美国 22 万例感染、1.2 万例死亡和超过 10 亿美元的医疗费用。它对多种抗生素具有高度耐药性，但我们对其如何感知和应对抗生素压力以及这种感应系统如何影响临床结果知之甚少。我们已经发现了一个自发的突变株，该突变株显示出增加的达托霉素耐药性。我们进行了全基因组测序，发现了一个无义突变 S605*，该突变位于编码双组分系统（TCS）的假定传感器组氨酸激酶的基因中。与野生型（WT）相比，*突变体的达托霉素 MIC 增加了约 4 至 8 倍。我们发现，WT 中组成型激活的 DraR 的表达将达托霉素耐药性增加了 8 至 16 倍，并将杆菌肽耐药性增加了约 4 倍。我们发现，包括万古霉素、杆菌肽、雷莫拉宁和达托霉素在内的一系列抑制脂质 II 的化合物会导致基于荧光素酶的报告基因 P 的活性增加。使用 RNA 测序（RNA-seq），我们确定了 DraRS 调控子。有趣的是，我们发现 DraRS 可以诱导先前鉴定的必需基因的表达，该基因用于合成在中产生的新型糖脂。我们的数据表明，DraR 诱导基因的表达解释了 DraR 诱导的达托霉素和杆菌肽耐药性的一部分，但不是全部。是医院获得性腹泻的主要原因，由于抗生素耐药性的流行和复发性感染的速度，这是一个紧急关注的问题。编码约 50 个注释的双组分系统（TCS）；然而，只有少数得到了研究。这些未研究的 TCS 的功能尚不清楚。在这里，我们表明 TCS DraRS 在响应一组脂质 II 抑制抗生素方面发挥作用，并通过诱导最近鉴定的基因的表达部分介导对达托霉素和杆菌肽的耐药性，该基因编码在中产生新型糖脂所需的酶。
