title: A prospective, randomised, double-blind study of comparative efficacy of immediate versus daily cleaning of stethoscope using 66% ethyl alcohol.
abstract: OBJECTIVE
  Studies have demonstrated frequent contamination of stethoscope and usefulness of different disinfectants. Albeit, studies on the precise mode of cleaning and frequency of cleaning are lacking. This study was carried out to determine efficacy of 66% ethyl alcohol as disinfectant, rate of recontamination without cleaning and benefits of daily versus immediate cleaning.
  
  
  METHODS
  Prospective, randomised, double blind study of 100 stethoscopes. Four cultures were obtained: before cleaning (Group A), immediately after cleaning with 66% ethyl alcohol (Group B), at the end of 4 days without cleaning (Group C) and at the end of 4 days after cleaning once a day (Group D). Samples were analysed using standard microbiological methods and Colony-forming unit (CFU) count and residual microorganism was computed for all the positive cultures. Medical staff was asked about the cleaning practices. Statistical analysis was carried out using 95% confidence interval and Chi-square test.
  
  
  RESULTS
  90% of the stethoscopes were contaminated with one or more microorganisms. Immediate cleaning and daily cleaning were associated with a significant reduction in the rate of contamination to 28% and 25% respectively. CFU count in groups B and D dropped to less than 10 in 75% and 84.7%, while the mean residual rates were 5.2% and 3.65% respectively. Groups B and D showed no statistically significant difference in terms of efficacy of disinfection.
  
  
  CONCLUSIONS
  66% ethyl alcohol is an effective disinfectant. The effects of immediate cleaning and cleaning once a day on residual flora on the diaphragm of stethoscope is comparable.
authors.affiliation: The Department of Paediatrics, Seth G.S. Medical College & K.E.M. Hospital, Parel, Mumbai-400 012, India. ramehsparmar@yahoo.com
authors.forename: Ramesh C
authors.initials: RC
authors.lastname: Parmar
authors.forename: Chayya C
authors.initials: CC
authors.lastname: Valvi
authors.forename: Poonam
authors.initials: P
authors.lastname: Sira
authors.forename: Jaishree R
authors.initials: JR
authors.lastname: Kamat
mesh_terms: D004202:Disinfectants; D004203:Disinfection / Q000379:methods*; D004311:Double-Blind Method; D000431:Ethanol; D006801:Humans; D011446:Prospective Studies; D019023:Stethoscopes; D013997:Time Factors
chemical_list: D004202:Disinfectants; D000431:Ethanol