How killed enterobacterial cultures can activate living organisms to resist lethal agents or conditions

• Published in: Science progress (1916) 2003-08, Vol.86 (3), p.157-178
• Main Author: ROWBURY, ROBIN J.
• Format: Article
• Language: English
• Subjects: Acid tolerance; Acidity; Alkalies; Alkalinity; Analysis; Antibiotics; Aquatic environment; Bacteria; Bacterial Physiological Phenomena; Bacterial Proteins - genetics; Bacterial Proteins - physiology; Bacteriophages; Cell Culture Techniques - methods; Cell division; Culture Media; Disinfection & disinfectants; DNA-Binding Proteins - genetics; DNA-Binding Proteins - physiology; Enterobacter; Enterobacteriaceae; Enzymes; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - physiology; Food; Food Microbiology; Food production; Gene Expression Regulation, Bacterial; Heat tolerance; Hydrogen peroxide; Immune tolerance; Inactivation; Ions; Irradiation; Lethal mutation; Microbiology; Natural waters; Public health; Risk factors; Sewage; Sewage effluent; Stress tolerance; Thermal stress; Water Microbiology; Water treatment
• ISSN: 0036-8504; 2047-7163
• DOI: 10.3184/003685003783238662

A major aim in many areas of microbiology is to ensure sterility, and even where this is impossible, to reduce the number of viable organisms occurring in particular environments to an absolute minimum. This applies in the aquatic environment, where e.g. water treatment must ensure as complete absence of viable microbes as possible. It is also crucial in food processing and production; many food constituents contain appreciable numbers of viable organisms, even potential pathogens, and the number must be greatly reduced and in many situations, the presence of viable organisms totally abolished. Cleaning of food production components and surfaces must also kill associated microbes. In domestic, hospital and commercial situations, similar disinfection is critical. Ultimately, the aim is to ensure, if possible, sterility, with the assurance that microbial problems cannot occur if organisms are absent. Additionally, however, it has been implicitly assumed that killed organisms and even killed cultures cannot (except in minor and trivial ways) influence the behaviour of living organisms that later enter the environment. The work reviewed here challenges that view and in fact disproves it. The findings described show that killed enterobacterial cultures, which prior to killing had phenoty pic ally gained the ability to resist potentially lethal stresses, can pass on such ability to living organisms that later enter their environment i.e. that such killed cultures can convey a baleful legacy to living ones. This phenomenon is so widespread that it is clear that it has significance for enterobacterial survival in natural waters, in foods and in food production, in the domestic, commercial and hospital situation, and in the animal and human body. In fact, in this last area, the likely effect of killed cultures appears to be of appreciable public health importance. Here, the ability of appropriate killed cultures to transfer tolerance to acidity, alkalinity and thermal stress is described, as well as their ability to pass on sensitisation to acid and alkali. Other work reviewed suggests that killed cultures can almost certainly transfer the ability to tolerate hydrogen peroxide, ultraviolet irradiation and metal ions. The serious implications of this phenomenon are further emphasised by the fact that numerous killing methods produce cultures effective in tolerance response transfer. All the evidence suggests that it is extracellular components (extracellular sensing