Hygiene IIIMark D. SobseyENVR 890-2Spring, 2009Handwashing with soap after toilet/cleaning child• Burkina 1% and 13% • Ghana 4% and 2%• Nigeria – and 10%• Brazil – and 16% • Peru 6% and 30%• Kyrgyzstan 18% and 0%• N. England 80% and 47%In the last 10-15 years hygiene has moved up the health agendaWhat has brought about the change ?• Infectious disease tends have increased for some agents• Food borne disease remains at unacceptably high levels• Person-to-person tranmsission is now seen a significant cause of spread of infectious intestinal & respiratory diseases• Antibiotic resistant strains - need to prevent spread• Viral agents - not treatable with antibiotics• Ongoing emergence of new hazardous agents, e.g SARS• “at risk” groups in the home and community: – elderly, very young, immune-compromised – up to 1 in 7 people in US belong to an “at risk” groupGood hygiene practice is key to reducing these risks - in many cases the first line of defenceTrends in Gastrointestinal Infections in England and Wales• Increases in the 1990s• Campylobacter and Salmonella• Increases in rotavirus illness• Suspected increases in viral etiologies like NorovirusesWhat Proportion of Gastrointestinal Infections Occurs in the Home?• Estimates of 50-80% in Europe• Sources and causes:– Inappropriate hygiene practice• Failure to wash hands• Failure clean high-risk areas– Domestic pets– Viruses, enteric and respiratory– Flies and other insect vectorsInfectious Disease Risks in the Home• Pathogen contamination is highest in the kitchen, bathroom and in the washing machine• Routine activities in these areas facilitate microbial spread and transmission• Commercial cleaning products vary in their efficacy in reducing pathogens• Product misuse undermines efficacy• Behavior of consumers is a big factor in pathogen spread and behavior change though education and communication is a challengeEnvironmental Contamination and Infectious Disease Transmission• Contact transmission, direct from body surface to body surface or indirect transmission via contaminated inanimate object, are main routes of microorganism (pathogen) transmission• Pathogens are on inanimate objects• They persist for days to weeks• Pathogens on inanimate objects in the environment can be transferred to hands/fingers and other parts of the body• Pathogens are on inanimate objects in the environment and are a source of transmission causing infectious disease• Environmental (e.g., surface) disinfection reduces pathogens and disease risksDried MS2 virus infectivity at 25oC on stainless steel z and ceramic tileSEffect of Different Cleaning Methods on Norovirus Presence on Surfaces• Melamine surfaces contaminated with NV in feces, diluted 1:10 or 1:80 in PBS• Detergent cleaning, even with 2ndwipe step, failed to decontaminate surfaces• Virus was spread to a clean surface and fingers via a wiping cloth in all but one case (transfer to fingers from most lightly contaminated surface)• Surface treated with HDC (5000 ppmavailable chlorine) for 1 min reduced NV completely• No-cross-contamination, except for one of the surfaces, which had the heavier soilingEvaluation of Hand Hygiene Methods and Agents:• Contaminate hands with bacteria and virus• Clean hands for 10 seconds by washing, wiping or rubbing methods• Test different cleaning agents• Recover microbes from hands (glove juice method)• Repeated challenges and recoveriesSickbert-Bennett, E.E., Weber, D.J., Gergen-Teague, M.F., Sobsey, M.D., Samsa, G.P.,Rutala, W.A. 2005 “Comparative efficacy of hand hygiene agents in the reduction of bacteria and viruses,” Amer. J. of Infection Control 33(2):67;Efficacy of Hand Hygiene Agents: Log10Reductions of S. marcescens after 1 and 10 Challenges(A) 60% ethyl alcohol; (B) 61% ethyl alcohol; (C) 62% ethyl alcohol; (D) 61% ethyl alcohol/1% CHG; (E) 70% ethyl alcohol/0.005% silver iodide; (F) 0.4% benzalkonium chloride; (G) 0.5% PCMX/40% SD alcohol; (H) 0.75% chlorhexidine gluconate; (I) 2% chlorhexidine gluconate; (J) 4% chlorhexidine gluconate; (K) 1% triclosan; (L) 0.2% benzethonium chloride; (M) nonantimicrobial control; (N) tap water control.Your parents were right: “Wash Your Hands!”Efficacy of Hand Hygiene Agents: Log10Reductions of Coliphage MS2 after 1 and 10 Challenges(A) 60% ethyl alcohol; (B) 61% ethyl alcohol; (C) 62% ethyl alcohol; (D) 61% ethyl alcohol/1% CHG; (E) 70% ethyl alcohol/0.005% silver iodide; (F) 0.4% benzalkonium chloride; (G) 0.5% PCMX/40% SD alcohol; (H) 0.75% chlorhexidine gluconate; (I) 2% chlorhexidine gluconate; (J) 4% chlorhexidine gluconate; (K) 1% triclosan; (L) 0.2% benzethonium chloride; (M) nonantimicrobial control; (N) tap water control.Your parents were right: “Wash Your Hands!”Summary of Hand Hygiene Results• At a short time (10 sec.), all agents but handwipes and 60% ethyl alcohol handrub were similar to non-antimicrobial and tap water controls• Reductions of 1.15 to 2.0 log10of Serratia marcescens• After 10 episodes (multiple episodes of contamination) handwashingagents with 0.75-4% CHG, 1% triclosan, 0.2% benzethonium chloride, nonantimicrobial soap handwash, and tap water alone were efficacious (>1.5 log10) in reducing bacteria• Only some effectively reduced viruses: water, soap, benzethonium Cl, and CHG, and CHG effectiveness declined greatly by 10 challenges• Alcohol-based handrubs and wipes were ineffective for virus reduction• Short contact times are effective in reducing transient hand flora– So, focus hand hygiene on improving compliance rather than increasing the duration of hand hygiene. – If shorter duration of hand hygiene improves compliance, greatercompliance should lead to reduced infections.Hand Hygiene at the Community Level• Minimum effect of a single handwashwith either plain or antimicrobial soap on the quantity of hand microflora• After 1 year, significant reduction of hand microflora counts by use of either soap• Sustained and consistent hand hygiene significantly microbial loads over time• Effects of handwashing on hand microflora may not be predictive of the effects on pathogen reduction or disease reductionAiello AE, Marshall B, Levy SB, Della-Latta P, Larson E. (2004) Relationship between triclosan and susceptibilities of bacteria isolated from hands in the community. AntimicrobAgents Chemother. 2004 Aug;48(8):2973-9Comparison of mean pre-and post-
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