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Hygienic Laundering of Clothing: Insights into Infection Prevention

This article explores the importance of hygienic laundering in domestic and healthcare settings, focusing on the risk of transmission of hygiene-related infections through clothing, bed linens, and towels. It discusses the role of laundry in controlling antibiotic resistance and reducing the spread of antibiotic-resistant strains. The article also examines the survival and spread of pathogens and resistant strains on fabrics, as well as the transfer of contamination through contact with hands and other fabrics. Epidemiological evidence linking transmission via clothing and linens to infection is also explored.

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Hygienic Laundering of Clothing: Insights into Infection Prevention

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  1. Hygienic laundering of clothing, bedlinens, towels etc in domestic and healthcare settings - new insights Sally F. Bloomfield International Scientific Forum on Home Hygiene London School of Hygiene and Tropical Medicine Dirk P. Bockmühl  Rhine-Waal University of Applied Sciences, Germany September 2016

  2. Is laundry a risk? • Major focus on hands as key transmission route of hygiene-related infections. • Increasing evidence – particularly common touch and food preparation surfaces - important part of the equation, • Supported by recent reviews: • Rutala and Webber, AJIC supplement 2013 --- et alia • Why is there no reference to fabrics (i.e. clothing and household linens) as common touch surfaces?

  3. Controlling antibiotic resistance: • Hygiene seen as a central strategy: • Reducing need for antibiotic prescribing • Reducing spread of AR strains • To what extent are clothing and household linens risk factors? • Are they contributing to incd prevalence of AR strains – skin (MRSA ) and bowel (MDR G -ves ) strains in hospital & community? • US: could preference for low temp laundering be exacerbating spread of CA MRSA ? • If we reduce silent spread of nasal/skin/bowel carriage in healthy community, can we reduce frequency of resistant infections in hospital & community ?

  4. IFH reviews of laundry hygiene 2011, 2013 • .The infection risks associated with clothing and household linens in home and everyday life settings, and the role of laundry (2011) International Scientific Forum on Home Hygiene. http://www.ifh-homehygiene.org/best-practice-review/infection-risks-associated-clothing-and-household-linens-home-and-everyday-life • Effectiveness of laundering processes used in domestic (home) settings (2013) International Scientific Forum on Home Hygiene. http://www.ifh-homehygiene.org/review/effectiveness-laundering-processes-used-domestic-home-settings-2013 •  Clothing, household linens, laundry and hygiene. http://www.ifh-homehygiene.org/factsheet/clothing-household-linens-laundry-and-home-hygiene • Since data came from community and hospital settings , findings equally relevant to all settings • More recent studies: • Honisch , Bockmuhl, Staminger. Impact of wash cycle time, temperature and detergent formulation on the hygiene effectiveness of domestic laundering. J Appl Microbiol 2014, 117(6):1787-97 • Brands, Brinkmann, Bloomfield and Bockmühl (2016) Microbicidal action of heat, detergents and active oxygen bleach as components of laundry hygiene. Tenside Surf. Det. 53, 495-501.

  5. Breaking the chain of Infection Sources of Infection People, contaminated food, domestic animals Way in Mouth, nose, RT. cuts, grazes Shedding Food particles, faeces, saliva, cough, sneeze, Survival and spread Hands, surfaces, cloths, clothing, linens, baths, basins, toilets, air

  6. Shedding of pathogens and resistant strains onto clothing etc • Enteric pathogens: • Norovirus: Vomiting  30 million particles • nvfaecal shedding  28 days • Rotavirus  1011 virions per g faeces. • S. aureus • between 30 and 60% of population are carriers • Around 106 shed daily on skin scales • Antibiotic resistant strains • 100mg faeces excreted onto underclothes=104 cfu/item • In community - increasing prevalence of MDR G-ves in bowel flora • e.g. UK community study - prevalence of CTX-M ESBL carriage in stools = 11.3%

  7. Survival on fabrics • Gram positive spp. - S. aureus, C. difficile • survive long periods (days to months) • Gram-negative species - E. coli and P. aeruginosa, • survival times  4 h or more • Viruses • 30 min  48 h • Norovirus – 3 months • Fungal species • 1 day  several weeks

  8. Transfer from contaminated fabrics by contact with hands and other fabrics • Transfer rates via hands • Rates from moist fabrics around 1-10%, • But can be up to 50%. • less ( 10x ) if fabric or hands are dry. • Transfer from contaminated to uncontaminated fabrics included in laundry cycle • i.e laundering can be an effective means of transmitting infection!!

  9. What sort of bioburdens of pathogens have been found on clothing?

  10. Epidemiological evidence of link to infection • No intervention studies identified, • 19 observational studies (1959-2010): identified transmission via clothing and linens as likely cause, or a significant risk factor. • 14/19 – community-based; 7/19 S. aureus/MRSA .

  11. Examples • US jail 2007. Outbreak : MRSA skin infection. Intervention included correcting the laundry process (thermostat defective, machines overloaded, soap malfunction) • Importance of laundering suggested by: • Laundry first area where change implemented  immediate decline of skin infections before other measures could be implemented • Several strains were circulating, suggesting community MRSA strains continually introduced during outbreak, • i.e. key is not preventing introduction of MRSA – but consistent QA of laundry processing 

  12. Studies by Larson et al. 2000-2003 • Impact of cleaning/hygiene practices in 238 New York households, 3 months. • Infections recorded: fever, cough, cold, diarrhoea, vomiting, sore throat, skin infection • Hygiene practices recorded: daily personal bathing/showering, bathroom and toilet cleaning, dishcloth care, use of antimicrobial products and laundry practices • Only practices significant association with infection risks were: • using hot water & using bleach for laundering was protective • using a communal laundry & not using bleach in communal laundering predictive of increased infection risk

  13. IFH concludes: • In both hospital and out of hospital settings, clothing, bed linen, towels etc are risk factors • for infection. • for spread of MRSA and faecal organisms carrying AR determinants (8 studies) • “How big is the risk?” • Probably less than for hands and contact surfaces because: • survival on porous fabric surfaces is lower • transfer rates from fabrics lower • Opportunities for transfer probably less frequent. • Risks increase where family/care home patient has infection or impaired immunity.

  14. Household appliances may themselves be a contamination hazard

  15. Washing machine and laundry as a reservoir and vehicle for transmission of ESBL- producing K. oxytoca in newborns • Increased carriage of K. Oxyctoca, pediatric unit , German hospital – potentially fatal infection • Phase 1: K Oxytoca found in ward sinks, hygiene interventions did not terminate “outbreak” • Phase 2: K Oxytoca found in door seals of laundry machine • Retrospective study showed only infants whose clothes were laundered in the machine became colonised • “Low risk” is not “no risk” – laundry must always be considered as potential route of transmission • Not just “soiled” laundry Exner et al – in press

  16. Managing infections risks through laundering

  17. Effectiveness of laundering processes • In domestic settings: • Move towards low temp laundering - to conserve energy • energy to heat water contributes largest part of environmental impact of laundry • Low temperature laundering associated with increased infection risk?

  18. How does laundering work? Physical removal. • Main cycle, dirt & microbes detached into wash water - “washed away” by rinse/spin cycles. Thermal inactivation. • Inactivation - increases as temperature increases. Chemical inactivation. • Some detergents contain activated oxygen bleach (AOB). Primarily to digest stains - also -> inactivation of microbes. • Surfactants may contribute some microbicidal action Other factors can contribute: drying and ironing

  19. IFH review 2013 of hygiene efficacy of laundering • 29 publications identified - data extracted • LR values on fabrics contaminated w. bacteria (13), fungi (5) and viruses (7) during machine wash cycles. • Major difficulty - variability in LR values from different studies • Arise from 2 main sources: • Lack of standardisation /control of test conditions (wash cycle time, number of rinses etc) • Modern domestic washing machines do not reach specified temperature : • Set at 60°C, max temperature 46-53°C, • Set at 40°C, max temperature 35-39°C.

  20. Summary of published LR data for laundering at 60°C (17 studies) Summary of data from IFH review “Effectiveness of domestic laundering”. www.ifh-homehygiene.org

  21. Hygiene efficacy determined using contaminated test swatches – effect of temp 15 min cycle time - LR factor – detergent Honisch , Bockmuhl, Staminger. Journal of Applied Microbiology 2014, 117(6):1787-97

  22. Hygiene efficacy of laundering – effect of AOB detergent 15 min cycle time - LR factor – detergent with and without AOB Honisch , Bockmuhl, Staminger. Journal of Applied Microbiology 2014, 117(6):1787-97

  23. Hygiene efficacy of laundering – effect of increasing cycle time 45 min cycle time - LR factor – detergent with and without AOB Honisch , Bockmuhl, Staminger. Journal of Applied Microbiology 2014, 117(6):1787-97

  24. Hygiene efficacy of laundering – effect of increasing cycle time 90 min cycle time - LR factor – detergent with and without AOB Honisch , Bockmuhl, Staminger. Journal of Applied Microbiology 2014, 117(6):1787-97

  25. Transfer of pathogens from contaminated to uncontaminated items during machine laundering 8 studies (5 bacteria, 3 viruses) showed: • if laundering does not eliminate pathogens from fabrics, this -> transfer to uncontaminated fabrics included in wash cycle • Increased survival correlates with increased transfer

  26. Understanding the kinetics of laundry hygiene • 2016 study - Suspension tests to determine separate contribution of kill/inactivation • How could we optimize low temp laundry cycles  hygiene efficacy equivalent to laundering at 60°C? Brands, B., Brinkmann, A., Bloomfield, S.F. and Bockmühl, D.P. (2016). Tenside Surf. Det. 53, 495-501.

  27. Microbicidal effect of heat LR (15 min): test organisms in water • 60°C has significant microbicidal effect • little or no contribution at 40°C or less Brands, B., Brinkmann, A., Bloomfield, S.F. and Bockmühl, D.P. (2016). Tenside Surf. Det. 53, 495-501.

  28. Microbicidal effect of detergent Increase in LR due to micrbicidal action of detergent (15 min): May contribute some but limited action - Note 0.3LR = 50% kill Brands, B., Brinkmann, A., Bloomfield, S.F. and Bockmühl, D.P. (2016). Tenside Surf. Det. 53, 495-501.

  29. Microbicidal effect of AOB Increase in LR due to microbicidal action of AOB (15 min) = LR AOB detergent – LR detergent only • AOB significant action even at 20°C • Less effective v. fungi Brands, B., Brinkmann, A., Bloomfield, S.F. and Bockmühl, D.P. (2016). Tenside Surf. Det. 53, 495-501.

  30. Key findings – efficacy increased by: Higher temperatures Hygiene level • All durations and test organisms Longer washing times • Depending on temperature and organism Activated oxygen bleach • Except C. albicans Indicates opportunities to sustained/improve hygiene efficacy - even at lower laundry temps

  31. What about C. difficile? (Lakdawallaet al. 2011 ECMID poster) • Evaluated if C. difficile could be detected on bed linen after laundering 71°C, 3 mins followed by steam press. • Six patients had diarrhoea and +ve stool toxin test. • Up to 103 cfu/100cm2 could be recovered from the bed linen even after laundering. • Should we be concerned? • Increasing prevalence of infection in the community • 50% of healthy neonates (<1 year old) are carriers • Infectious dose not known (may be as little as 10 spores?) • What can we do? • For care homes – ozone disinfection system (DOH rapid review panel) (JLA stand 34) • For domestic home?

  32. So what LR do we need? • Is e.g 6 LR satisfactory/necessary to eliminate infection risk associated with clothing and household linens? • Is decreased LR at low temperatures associated with a significant increase in infection risk? • QMRA being used to assess impact of laundering (i.e LR values) on infection rates • suggests decrease in hygiene efficacy - say 5 to 3 LR - can translate into significant increase in infection rates • not detectable in a small community e.g care home • In public health translates into significant increase in national population of 60 million.

  33. QMRA study - assessing the impact of laundering on infection rates QMRSA - Infection risk from hand-to-mouth transfer of Shigella following contact with soiled compared with laundered clothing Gibson et al, 1999 AJIC27, s34- s39 • Infection risk reduction from increased LR may be insignificant for an individual, but translates into significant decrease in disease in national population of 60 million. • What is acceptable infection risk e.g 10-6, what LR is required to achieve this?

  34. Need more QMRA studies to determine LR values required to reduce infection risk to an acceptable level:

  35. QMRA study of hand to mouth transmission of E. coli from non porous surfaces • infection risk determined for transfer • Contaminated surface--- fingers ---------- mouth, nose ,eyes • Existing data extracted from the literature on • surface bioburden, transfer efficiency, exposure, infectious dose etc. • 7 microbial species • Safety target level: 1 in 1 million (10_6) risk of infection per touch (acceptable daily risk for drinking water) • Ryan, Haas, Gerba et al . Application of QMRA for selection of microbial reduction targets for hard surface disinfectants. American Journal of Infection Control 42 (2014) 1165-72.

  36. QMRA study of hand to mouth transmission from hard surfaces • But – estimate based on ambient microbial bioburdens, not e.g:. • person actively shedding pathogens • where salmonella-contaminated chicken placed on kitchen surface, • i.e not for critical control points at critical times in domestic or healthcare setting?.  

  37. IFH recommendations for domestic laundering (IFH consensus view) IFH fact sheet: Clothing, household linens, laundry and home hygiene www/ifh-homehygiene.org

  38. How do we identify laundry products containing AOB?

  39. Conclusions • Laundry Infection risks – although less than hands etc - must be suitably managed as part of multibarrier approach to hospital and community settings. • Must include managing risks of spread of AR strains and C.diff • Hygiene standards of laundering must be sustained • Lobby laundry detergent/appliance manufacturers to take laundry hygiene more seriously i.e take account of hygiene as well as sustainability • Visibly clean is not necessarily hygienically clean • ensure laundry machine reaches specified temperatures • Develop ways (products/appliances) which ensure hygiene efficacy of machine laundering is sustained - as well as sustainable

  40. Thanks to Prof Dirk P. Bockmühl  Britta Brands, Angel Brinkman, M. Honisch Rhine-Waal University of Applied Sciences, Germany Rainer Staminger University of Bonn

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