Castro-Rosas Javier, Gómez-Aldapa Carlos Alberto, Villagómez Ibarra José Roberto, Santos-López Eva María, Rangel-Vargas Esmeralda
Área Académica de Química. Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Ciudad del Conocimiento, Carretera Pachuca-Tulancingo km. 4.5. Mineral de la Reforma, Hgo., C.P. 42184. México.
FEMS Microbiol Lett. 2017 Oct 16;364(19). doi: 10.1093/femsle/fnx188.
Several reports have suggested that the viable but non-culturable (VBNC) state is a resistant form of bacterial cells that allows them to remain in a dormant form in the environment. Nevertheless, studies on the resistance of VBNC bacterial cells to ecological factors are limited, mainly because techniques that allow this type of evaluation are lacking. Differential scanning calorimetry (DSC) has been used to study the thermal resistance of culturable bacteria but has never been used to study VBNC cells. In this work, the heat resistance of Escherichia coli cells in the VBNC state was studied using the DSC technique. The VBNC state was induced in E. coli ATCC 25922 by suspending bacterial cells in artificial sea water, followed by storage at 3 ± 2°C for 110 days. Periodically, the behaviour of E. coli cells was monitored by plate counts, direct viable counts and DSC. The entire bacterial population entered the VBNC state after 110 days of storage. The results obtained with DSC suggest that the VBNC state does not confer thermal resistance to E. coli cells in the temperature range analysed here.
几份报告表明，活的但不可培养（VBNC）状态是细菌细胞的一种抗性形式，使它们能够以休眠形式存在于环境中。然而，关于VBNC细菌细胞对生态因子抗性的研究有限，主要是因为缺乏进行此类评估的技术。差示扫描量热法（DSC）已被用于研究可培养细菌的热抗性，但从未用于研究VBNC细胞。在这项工作中，使用DSC技术研究了处于VBNC状态的大肠杆菌细胞的耐热性。通过将细菌细胞悬浮在人工海水中，然后在3±2°C下储存110天，诱导大肠杆菌ATCC 25922进入VBNC状态。定期通过平板计数、直接活菌计数和DSC监测大肠杆菌细胞的行为。储存110天后，整个细菌群体进入VBNC状态。DSC获得的结果表明，在此处分析的温度范围内，VBNC状态并未赋予大肠杆菌细胞耐热性。
