title: Chloraminated drinking water does not generate bacterial resistance to antibiotics in Pseudomonas aeruginosa biofilms.
abstract: OBJECTIVE
  To determine if exposure of Pseudomonas aeruginosa biofilms to chloraminated drinking water can lead to individual bacteria with resistance to antibiotics.
  
  
  RESULTS
  Biofilms of P. aeruginosa PA14 were grown in drinking water in a Kadouri drip-fed reactor; the biofilms were treated with either 0.5 mg l(-1) or 1.0 mg l(-1) of chloramine for 15 or 21 days; control biofilms were grown in water without chloramine. Fewer isolates with antibiotic resistance were obtained from the chloramine-treated biofilms as compared to the control. Minimum inhibitory concentrations (MIC) for selected antibiotic-resistant isolates were determined using ciprofloxacin, tobramycin, gentamicin, rifampicin and chloramphenicol. All of the isolates tested had increased resistance over the wildtype to ciprofloxacin, rifampicin and chloramphenicol, but were not resistant to tobramycin or gentamicin.
  
  
  CONCLUSIONS
  Under these test conditions, there was no detectable increase in antibiotic resistance in P. aeruginosa exposed as biofilms to disinfectant residues in chloraminated drinking water.
  
  
  CONCLUSIONS
  Chloramine in drinking water, while unable to kill biofilm bacteria, does not increase the potential of P. aeruginosa to become resistant to antibiotics.
authors.affiliation: Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: D J
authors.initials: DJ
authors.lastname: Jurgens
authors.forename: S A
authors.initials: SA
authors.lastname: Sattar
authors.forename: T F
authors.initials: TF
authors.lastname: Mah
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D019149:Bioreactors; D002700:Chloramines / Q000494:pharmacology*; D004202:Disinfectants / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology; D014871:Water Microbiology; D014881:Water Supply / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D002700:Chloramines; D004202:Disinfectants; C030816:chloramine