Abstract

Disinfection technologies, especially light-based disinfection, have undergone tremendous development and innovation, but this treatment can cause bacteria to enter viable but nonculturable (VBNC) state. Due to their strong tolerance, VBNC bacteria cannot be completely removed by disinfection technologies, thereby posing a potential risk for antibiotic resistance gene (ARG) transfer. Therefore, to better understand VBNC bacteria and interpret potential transfer of ARGs, this article systematically reviewed changes in morphology, physiology and virulence of bacteria after entering VBNC state. In addition, this article reviewed quantitative detection methods of VBNC bacteria, such as cell membrane integrity-mediated LIVE/DEAD Baclight assay, qPCR-based assays, and phage-based detection methods, concluding that there is still a lack of in-situ and real-time detection methods for VBNC bacteria. Health risks and environmental application value of VBNC bacteria were then valuated, with data indicating that VBNC bacteria have great value in the domain of microbial utilization. Furthermore, the induction conditions (especially by light-based disinfection) and formation mechanisms of VBNC bacteria were highlighted. Formation mechanisms mainly involve stringent response, general stress response system and toxin-antitoxin (TA) system. Moreover, horizontal gene transfer (HGT) of ARGs during and after the formation of VBNC bacteria induced by light-based disinfection was evaluated. It was found that ARGs may be transferred through conjugation, transformation and transduction. Finally, current deficiencies and future challenges for the transformation of VBNC bacteria, especially those influenced by light-based disinfection technologies, were summarized. This review provides new insights into detection methods, formation mechanisms, environmental applications and potential ARG transfer risks of VBNC bacteria.

摘要

消毒技术，尤其是基于光的消毒，经历了巨大的发展和创新，但这种处理会导致细菌进入可存活但不可培养（VBNC）状态。VBNC 细菌由于耐受性强，不能通过消毒技术完全去除，从而对抗生素抗性基因 (ARG) 转移构成潜在风险。因此，为了更好地了解VBNC细菌并解释ARGs的潜在转移，本文系统地回顾了细菌进入VBNC状态后形态、生理和毒力的变化。此外，本文还综述了VBNC细菌的定量检测方法，如细胞膜完整性介导的LIVE/DEAD Baclight检测、基于qPCR的检测方法和基于噬菌体的检测方法，结论仍然缺乏VBNC细菌的原位和实时检测方法。然后对VBNC细菌的健康风险和环境应用价值进行了评估，数据表明VBNC细菌在微生物利用领域具有很大的价值。此外，还强调了 VBNC 细菌的诱导条件（尤其是光消毒）和形成机制。形成机制主要涉及严格反应、一般应激反应系统和毒素-抗毒素（TA）系统。此外，评估了基于光的消毒诱导的 VBNC 细菌形成期间和之后的 ARGs 水平基因转移 (HGT)。发现ARGs可以通过缀合、转化和转导进行转移。最后，总结了目前VBNC细菌转化的不足和未来挑战，特别是那些受光消毒技术影响的细菌。本综述为 VBNC 细菌的检测方法、形成机制、环境应用和潜在的 ARG 转移风险提供了新的见解。