OBJECTIVES: Polyquaternium-1 (PQ-1) is a biocide used commercially in a contact lens disinfecting solution, 'Opti-Free Express (Alcon) Multi-Purpose Disinfecting Solution'. The genetic basis for resistance of Serratia marcescens to PQ-1 was investigated using a random transposon-based mutagenesis approach.
METHODS: S. marcescens was subjected to random transposon mutagenesis using a mini-Tn5 Km2 transposon. Mutants with increased susceptibility to PQ-1 were selected and the disrupted genes were identified. Antibiotic susceptibility profiles were also determined for all of the mutants.
RESULTS: A wide range of genes were found to be disrupted in the mutants. The most common were genes associated with the cell membranes, or involved in biosynthesis and metabolism.
CONCLUSIONS: This study shows that random transposon mutagenesis is an effective tool for the elucidation of mechanisms of action and resistance to biocides. The results support our previous findings that PQ-1 is active against the cytoplasmic membrane of S. marcescens.
- Blotting, Southern
- Contact Lens Solutions/pharmacology
- Culture Media
- DNA Transposable Elements/genetics
- DNA, Bacterial/genetics
- Genes, Bacterial/genetics
- Microbial Sensitivity Tests
- Mutagenesis, Insertional
- Serratia marcescens/drug effects