Abstract: 1. General Discussion

Natural and built aquatic environments can stress bacteria via multiple conditions or processes, including low or variable nutrient concentrations, osmotic pressure, changes in pH, temperature, ultraviolet irradiation, microbial competition, heavy metals, biocides, or disinfectants and oxidants.

The physiological status of the microorganism must be considered when selecting a method for detection and enumeration. This section addresses the viable but nonculturable (VBNC) state, which is a physiological response of the organism to stress, and the injured state, which is a physiological lesion caused by a stressor. Although the loss of culturability results from both states, the effect on method selection and detection are quite different.