title: Evaluation of the efficacy of bleach routinely used in health facilities against Mycobacterium tuberculosis isolates in Ethiopia.
abstract: BACKGROUND
  In Ethiopia, the most widely used disinfectant is 5% Hypochlorites. However, Ethiopian national health safety and infection prevention guideline recommendation on the use of bleach is not consistent and varying from 0.1%-4%. The purpose of this study was therefore to assess the effective time-concentration relationship of sodium hypochlorite against Mycobacterium tuberculosis complex isolates in the absence of any organic load.
  
  
  METHODS
  This experimental study was conducted in Bahir Dar Regional laboratory from February-June 2013. Test suspensions of 1.5 X 10(8) CFU/ml prepared using normal saline containing 0.5% tween 80. From 5% stock, 0.1%, 0.5%, 1% and 2% bleach was prepared. A 1ml of test strain suspension and 1ml of bleach mixed and allowed to stand until the specified time achieved, neutralized by 48 ml phosphate buffer. 100µl from the diluted sediment were spread on two L-J mediums and incubated at 37°C for 8 weeks.
  
  
  RESULTS
  When 0. 1% bleach was used for 10 min, majority 11/20 of isolates showed 3 x 10(3) CFU/ml growth (ME = 4.4) which was inefficient. However, when the time increased, the log10 reduction was acceptable, ME >5 and it was effective. The bleach solution containing 0.5% and above was effective in all respective times. In this study, there is no difference observed in the tuberculocidal activity of bleach against resistant and sensitive strains.
  
  
  CONCLUSIONS
  Our study showed that in the absence of any organic load, 0.1% bleaches over 15 min and 0.5% bleaches over 10 min was found to be tuberculocidal.
authors.affiliation: Bahir Dar University, College of Medicine and Health Sciences, Department of Medical Microbiology, Immunology and Parasitology, Bahir Dar, Ethiopia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mekonnen
authors.affiliation: Bahir Dar Regional Health Research Laboratory Center, Department of Regional Mycobacteriology Laboratory, Bahir Dar, Ethiopia.
authors.forename: Aschalew
authors.initials: A
authors.lastname: Admassu
authors.affiliation: Bahir Dar University, College of Medicine and Health Sciences, School of Public Health.
authors.forename: Belaynew
authors.initials: B
authors.lastname: Wassie
authors.affiliation: Bahir Dar University, College of Medicine and Health Sciences, Department of Medical Microbiology, Immunology and Parasitology, Bahir Dar, Ethiopia ; Institute of Medical Microbiology and Epidemiology of Infectious Diseases, Medical Faculty, University of Leipzig, Germany.
authors.forename: Fantahun
authors.initials: F
authors.lastname: Biadglegne
mesh_terms: D004202:Disinfectants / Q000008:administration & dosage / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005002:Ethiopia; D006268:Health Facilities; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D017410:Practice Guidelines as Topic; D012973:Sodium Hypochlorite / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors; D014376:Tuberculosis / Q000517:prevention & control
chemical_list: D004202:Disinfectants; D012973:Sodium Hypochlorite
keywords: Bleach; Efficacy; Ethiopia; M. tuberculosis; organic load