Hamabata Takashi, Senoh Mitsutoshi, Iwaki Masaaki, Nishiyama Ayae, Yamamoto Akihiko, Shibayama Keigo
Research Institute, National Center for Global Health and Medicine, Tokyo 162-8655, Japan.
Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo 208-0011, Japan.
Microorganisms. 2021 Apr 26;9(5):927. doi: 10.3390/microorganisms9050927.
Many pathogenic bacteria, including and , can become viable but nonculturable (VBNC) following exposure to specific stress conditions. , a known human pathogen causing diphtheria, has not previously been shown to enter the VBNC state. Here, we report that can become VBNC when exposed to low temperatures. Morphological differences in culturable and VBNC were examined using scanning electron microscopy. Culturable cells presented with a typical rod-shape, whereas VBNC cells showed a distorted shape with an expanded center. Cells could be transitioned from VBNC to culturable following treatment with catalase. This was further evaluated via RNA sequence-based transcriptomic analysis and reverse-transcription quantitative PCR of culturable, VBNC, and resuscitated VBNC cells following catalase treatment. As expected, many genes showed different behavior by resuscitation. The expression of both the diphtheria toxin and the repressor of diphtheria toxin genes remained largely unchanged under all four conditions (culturable, VBNC, VBNC after the addition of catalase, and resuscitated cells). This is the first study to demonstrate that can enter a VBNC state and that it can be rescued from this state via the addition of catalase. This study helps to expand our general understanding of VBNC, the pathogenicity of VBNC , and its environmental survival strategy.
许多致病细菌，包括[细菌名称1]和[细菌名称2]，在暴露于特定应激条件下后会进入活的但不可培养（VBNC）状态。[细菌名称3]是一种已知的导致白喉的人类病原体，此前尚未被证明能进入VBNC状态。在此，我们报告[细菌名称3]在暴露于低温时可进入VBNC状态。使用扫描电子显微镜检查了可培养的和VBNC状态的[细菌名称3]的形态差异。可培养的细胞呈现典型的杆状，而VBNC细胞则显示出中心扩张的扭曲形状。在用过氧化氢酶处理后，细胞可以从VBNC状态转变为可培养状态。通过基于RNA序列的转录组分析以及对可培养的、VBNC状态的和过氧化氢酶处理后复苏的VBNC细胞进行逆转录定量PCR，对此进行了进一步评估。正如预期的那样，许多基因在复苏后表现出不同的行为。在所有四种条件下（可培养的、VBNC状态的、添加过氧化氢酶后的VBNC状态的和复苏后的细胞），白喉毒素和白喉毒素基因阻遏物的表达基本保持不变。这是第一项证明[细菌名称3]可进入VBNC状态且可通过添加过氧化氢酶从该状态中复苏的研究。这项研究有助于扩展我们对VBNC、VBNC状态的[细菌名称3]的致病性及其环境生存策略的总体认识。
