The survival and growth of an environmental Klebsiella isolate in detergent solutions

A Klebsiella isolate (G1) was capable of survival and growth in an environment containing high levels of anionic (15.6%) and non-ionic detergent (7.8%). Cell numbers were monitored by traditional viable plate counts (culturability), and by staining with Rhodamine 123 (vital counts) and Acridine Orange (total counts). On inoculation into detergent solutions, only 10% of cells retained vitality (rhodamine 123) after 24 h. Of those, only 1% were able to form colonies on artificial culture media. Under low nutrient conditions (TOC < 0.89 mg l - 1), no recovery was observed over a 96 h period, but addition of nutrients (TOC 3.84 mg l - 1) allowed recovery within 48 h. Such cells were initially (24 h) elongated, but subsequently (144 h) returned to their normal size. In the presence of detergent without added nutrient, cell size was reduced after 144 h. After adaptation to the detergent environment (24 - 48 h), cell numbers in detergent with added nutrient broth (vital, viable and total) rose, until levels equivalent to those of a detergent-free control were attained. Detergent solutions provide a stressful environment. Nutrient levels in the detergent solutions affected cell size and the ability of the Klebsiella (G1) to survive and grow.