title: Identification of genes involved in the susceptibility of Serratia marcescens to polyquaternium-1.
abstract: OBJECTIVE
  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.
authors.affiliation: Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3XF.
authors.forename: Caroline E
authors.initials: CE
authors.lastname: Codling
authors.forename: Brian V
authors.initials: BV
authors.lastname: Jones
authors.forename: Eshwar
authors.initials: E
authors.lastname: Mahenthiralingam
authors.forename: A Denver
authors.initials: AD
authors.lastname: Russell
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Maillard
mesh_terms: D015139:Blotting, Southern; D018639:Contact Lens Solutions / Q000494:pharmacology*; D003470:Culture Media; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D016254:Mutagenesis, Insertional; D011108:Polymers / Q000494:pharmacology*; D012706:Serratia marcescens / Q000187:drug effects* / Q000235:genetics*
chemical_list: D018639:Contact Lens Solutions; D003470:Culture Media; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D011108:Polymers; C058655:polyquaternium 1