Detergent-shock response in enteric bacteria

Our work on bacterial detergent resistance started with the realization that bacteria growing in a sink full of soap must be resistant to the detergents in that soap. We chose sodium dodecyl sulphate (SDS) as a model detergent and decided to see how much SDS the bacterium growing in the sink could tolerate. The research program thus initiated has shown that bacteria such as Enterobacter cloacae can grow in up to 25% SDS and that SDS-shock proteins constitute c. 8% of the proteins synthesized by SDS-grown Escherichia coli. It has also provided explanations why enteric bacteria are oxidase negative, and how pyrroloquinoline quinone (PQQ) enters the periplasmic space. Finally, for E. coli, it has provided evidence for an alternate, phosphate-limited, aquatic life style which places greater emphasis on the Entner-Doudoroff pathway. Detergent resistance is important both medically and ecologically, e.g. entry of pathogens via bile-salt-containing intestinal tracts and biodegradation of detergent-like pollutants such as those resulting from oil spills. Our current research is focused on SDS-induced modifications of the cytoplasmic membrane and the presence of SDS in the periplasm.