title: Decontamination of Bacillus subtilis var. niger spores on selected surfaces by chlorine dioxide gas.
abstract: OBJECTIVE
  Chlorine dioxide (CD) gas has been used as a fumigant in the disinfection of biosafety laboratories. In this study, some experiments were conducted to assess the inactivation of spores inoculated on six materials [stainless steel (SS), painted steel (PS), polyvinyl chlorid (PVC), polyurethane (PU), glass (GS), and cotton cloth (CC)] by CD gas. The main aims of the study were to determine the sporicidal efficacy of CD gas and the effect of prehumidification before decontamination on sporicidal efficacy.
  
  
  METHODS
  Material coupons (1.2 cm diameter of SS, PS, and PU; 1.0 cm×1.0 cm for PVC, GS, and CC) were contaminated with 10 μl of Bacillus subtilis var. niger (ATCC 9372) spore suspension in mixed organic burden and then dried in a biosafety cabinet for 12 h. The spores were recovered by soaking the coupons in 5 ml of extraction liquid for 1 h and then vortexing the liquid for 1 min.
  
  
  RESULTS
  The log reductions in spore numbers on inoculated test materials exposed to CD gas [0.080% (volume ratio, v/v) for 3 h] were in the range of from 1.80 to 6.64. Statistically significant differences were found in decontamination efficacies on test material coupons of SS, PS, PU, and CC between with and without a 1-h prehumidification treatment. With the extraction method, there were no statistically significant differences in the recovery ratios between the porous and non-porous materials.
  
  
  CONCLUSIONS
  The results reported from this study could provide information for developing decontamination technology based on CD gas for targeting surface microbial contamination.
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China. liyj@npec.org.cn
authors.forename: Yan-ju
authors.initials: YJ
authors.lastname: Li
authors.forename: Neng
authors.initials: N
authors.lastname: Zhu
authors.forename: Hai-quan
authors.initials: HQ
authors.lastname: Jia
authors.forename: Jin-hui
authors.initials: JH
authors.lastname: Wu
authors.forename: Ying
authors.initials: Y
authors.lastname: Yi
authors.forename: Jian-cheng
authors.initials: JC
authors.lastname: Qi
mesh_terms: D001412:Bacillus subtilis / Q000187:drug effects* / Q000254:growth & development*; D002470:Cell Survival / Q000187:drug effects; D017606:Chlorine Compounds / Q000494:pharmacology*; D003666:Decontamination / Q000379:methods*; D004202:Disinfectants / Q000494:pharmacology*; D005740:Gases / Q000494:pharmacology; D010087:Oxides / Q000494:pharmacology*; D013171:Spores, Bacterial / Q000187:drug effects* / Q000254:growth & development*; D013499:Surface Properties
chemical_list: D017606:Chlorine Compounds; D004202:Disinfectants; D005740:Gases; D010087:Oxides; C025109:chlorine dioxide