title: Microbiological Load of Ethylene Oxide Sterilized Medical Devices and its Elimination by Cobalt 60 Source.
abstract: OBJECTIVE
  To determine the residing microbial flora of ethylene oxide (EtO) sterilized medical devices and optimization of safe dose of gamma radiation (Cobalt 60 source) for the complete elimination of microbial load.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Department of Biotechnology, Lahore College for Women University, Lahore, Pakistan from September 2014 to June 2015.
  
  
  METHODS
  Thirty-six samples of EtO sterilized medical devices of same batch of three different companies were collected for this study. Isolation and enumeration of microbes were done by using different selective and differential media. Gram staining and biochemically characterization by API 20 (Bio Merieux, France) kit was done for identification of the microorganisms. The medical devices having high microbial load were sent to Pakistan Radiation Services (PARAS) for gamma irradiations at 3 different selected doses (20 KGy, 25 KGy, and 30 KGy).
  
  
  RESULTS
  Different types of Gram positive bacteria (Staphylococcus epidermidis, Staphylococcus aureus andBacillus subtilis) were isolated from the EtO sterilized samples. Gram negative bacteria and fungi were not detected on these medical devices. Gamma irradiations results showed that 30 KGy was optimized dose for complete elimination of microbial flora on endotracheal, Nelaton, and tracheostomy tubes.
  
  
  CONCLUSIONS
  Gamma radiations (Co 60 source) effectively decontaminate the microbial flora on the equipment previously sterilized by the ethylene oxide gas; and 30 KGy is the optimized dose for all these medical devices.
authors.affiliation: Department of Biotechnology, Lahore College for Women University, Lahore.
authors.forename: Rasheeda
authors.initials: R
authors.lastname: Bashir
authors.affiliation: Department of Biotechnology, Lahore College for Women University, Lahore.
authors.forename: Bakht
authors.initials: B
authors.lastname: Afroze
authors.affiliation: Department of Biotechnology, Lahore College for Women University, Lahore.
authors.forename: Hafiza Fizza
authors.initials: HF
authors.lastname: Zulfiqar
authors.affiliation: Department of Biotechnology, Lahore College for Women University, Lahore.
authors.forename: Resham
authors.initials: R
authors.lastname: Saleem
authors.affiliation: WTO, Quality Operational Laboratory (QOL), University of Veterinary and Animal Sciences, Lahore.
authors.forename: Imran
authors.initials: I
authors.lastname: Altaf
authors.affiliation: Department of Biotechnology, Lahore College for Women University, Lahore.
authors.forename: Faiza
authors.initials: F
authors.lastname: Saleem
authors.affiliation: Department of Biotechnology, Lahore College for Women University, Lahore.
authors.forename: Farheen
authors.initials: F
authors.lastname: Aslam
authors.affiliation: Department of Biotechnology, Lahore College for Women University, Lahore.
authors.forename: Shagufta
authors.initials: S
authors.lastname: Naz
mesh_terms: D015169:Colony Count, Microbial; D004202:Disinfectants / Q000494:pharmacology*; D004203:Disinfection / Q000295:instrumentation / Q000379:methods*; D004866:Equipment Contamination; D004869:Equipment Safety; D004864:Equipment and Supplies / Q000382:microbiology*; D005027:Ethylene Oxide / Q000494:pharmacology*; D005720:Gamma Rays; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000528:radiation effects*; D006801:Humans; D011829:Radiation Dosage; D013242:Sterilization / Q000379:methods*
chemical_list: D004202:Disinfectants; D005027:Ethylene Oxide