Cleaning methods

Edwards, N. W. M. et al. 2020. Recontamination of Healthcare Surfaces by Repeated Wiping with Biocide-Loaded Wipes: “OneWipe, One Surface, One Direction, Dispose” as Best Practice in the Clinical Environment.

Objectives

  • To study how the surface to be wiped, the type of fibre in the wipe and how the presence of liquid biocide affects the degree of recontamination.
    • metal, ceramic, and plastic healthcare surfaces
    • 2 different wipe compositions (hygroscopic and hydrophilic)
    • with and without liquid biocide.

Results

  • Despite initially high removal efficiency of >70 % during initial wiping, all healthcare surfaces were recontaminated with E. coli, S. aureus and E. faecalis when wiped more than once using the same wipe.
  • Recontamination occurred regardless of the fibre composition of the wipe or the presence of a liquid biocide.
  • The extent of recontamination by E. coli, S. aureus and E. faecalis bacteria also increased when metal healthcare surfaces possessed a higher microscale roughness (<1 μm).

Conclusion

“One wipe, One surface, One direction, Dispose” policy should be implemented and rigorously enforced.


Berendt, A.E. et al. 2011. Three swipes and you’re out: How many swipes are needed to decontaminate plastic with disposable wipes?

Objective

  • To measure the ability of various wipes to reduce bacterial counts when swiped across plastic 1, 3, or 5 times.

Methods

  • Dilutions of 0.5 McFarland (1.5 3 108 colony-forming units/ml) suspensions of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant.
  • Enterococcus faecalis (VRE), and Pseudomonas aeruginosa, as well as a 2.0 McFarland suspension of Candida albicans, were prepared in sterile saline.
  • To mimic contaminate surfaces, 100 ml of each suspension were streaked evenly onto sterile plastic Petri dishes and allowed to dry.
  • Each dish was then rubbed 1, 3, or 5 times with
    • a saline-moistened tissue (saline= water and salt, sodium chloride, NaCl), wet wiping
    • a 5% ethanol wipe
    • a quaternary ammonium wipe with 14.30 % isopropanol and 0.23 % di-isobutylphenoxyethyl dimethyl benzyl ammonium chloride
    • a 0.5 % hydrogen peroxide wipe
    • a 0.5 % chlorhexidine-70 % isopropyl alcohol wipe.
  • Contact time 1 second per swipe (after allowed to dry 10 min).
  • The plate surfaces were then flooded with 1 ml of trypticase soy broth, to resuspend any remaining bacteria.
  • 100 μl of the suspension was cultivated on blood agar plates for 24 hours and colonies calculated after that.

Results

  • For all 5 wipe types, swiping the surface 3 or 5 times eliminated more bacteria than only one swipe.
  • According to authors, “dramatic decreases” in bacterial counts with an increasing number of swipes, regardless of the type of wipe used (including saline-moistened tissues)
  • Swiping 3 times decreased the bacterial load by 88% (on average) relative to swiping just once.
  • When the surface was swiped 3 or more times, the saline wipe appeared to be equally effective as disinfectant wipes.

Conclusions

  • When surfaces are swiped 3 or more times, a saline-moistened wipe appears to be just as effective as disinfectant wipes.
  • When swiped only once, then a disinfectant wipe should be used.

Edwards, N. W. M. et al. 2018. Factors affecting removal of bacterial pathogens from healthcare surfaces during dynamic wiping.

Objectives

  • To determine the intrinsic (e.g., wipe surface density, lotion addition to wipe) and extrinsic (e.g., wiping pressure) factors leading to the greatest bacterial removal efficiencies.

Methods

  • Test microbes: E. coli, S. aureus, and E. faecalis
  • Wipes were manufactured for the research in laboratory
    • an inherently hydrophilic regenerated cellulose fiber (lyocell) and
    • an inherently hydrophobic fiber (polypropylene – PP) were selected as raw materials for wipe fabric manufacture
    • with different properties.
  • Wiping pressures were selected based on those produced by an average sized human hand and the median value reported in the literature.
    • “Low” wiping pressure of 0.69 kN.m–2 is the equivalent of 1 kg of exerted force from an average sized human hand (‘‘hand-weight’’).
    • “Medium” wiping pressure of 4.68 kN.m–2 is equivalent to 6.79 kg ‘‘handweight’’. This was selected by extrapolating the 150 g ‘‘exerted weight’’ used by Ramm et al. in their wiping experiments.
    • “High” 13.80 kN.m–2 wiping pressure is the equivalent of 20 kg ‘‘hand-weight’’.
  • The influence of a biocidal liquid was compared with distilled water and dry controls
    • Biocide was a blend of a non-ionic surfactant (C9–C11 ethoxylated alcohol pareth-5), a cationic surfactant (benzalkonium chloride) and various buffering agents and sequestrants.
  • Wiping done with a certain rotation device 60 r min–1 for 10 s at either 0.68, 4.69 or 13.80 kN.m–2.

Results

  • The addition of a biocide to a wipe has the greatest effect on bacterial removal %.
  • The improvement in wiping efficiency due to the addition of the biocidal liquid might also be partly due to the presence of a liquid phase, and not just the fact that it is a biocidal liquid.
  • The addition of water alone can substantially increase bacteria removal from the surface by providing a transport medium in which bacteria can be suspended and transported by the interstitial pore spaces within the wipe fabric structure.
  • The heaviest wipes, 150 g.m–2, consistently yielded greater bacteria removal efficiency than the 50 and 100 g.m–2 wipes (more fibers, more contacts on surface, more removal).

Conclusions

  • Best practice for infection control should involve
    • use of heavier weight
    • regenerated cellulosic wipes
    • impregnated with biocide
    • with as much wiping pressure as possible.

Andersen, B. M. et al. 2009. Floor cleaning: effect on bacteria and organic materials in hospital rooms.

Objectives

  • To examine the load of organic materials and bacteria (colony-forming units: cfu) on the floors in patient rooms during ordinary use.
  • To compare the results of two different ATP devices.
  • To study the effect of four floor cleaning methods on the presence of organic materials and bacteria.
  • Methods: dry, spray, moist and wet mopping.

Methods

  • For assessment of soiling: ATP (from floor) and microbiological samples (from floor and air).
  • An SAS air sampler was used to take air samples before and after cleaning.
  • Agent: detergent (Allrent) and water.
  • Four two-bed rooms, floor material: vinyl
  • Swep mops, moved in a figure of 8
    • dry mopping: 50 cm, 100 % microfibre
    • spray mopping: 50 cm, dry mop, 95 % microfibre, 150-200 ml water with detergent was added to the floor before washing
    • moist mopping: mop as above, was moist after washing at temperature up to 85°C and centrifugation for 3-5 min, put in a clean plastic bag and placed in cooler until next morning
    • wet mopping: Blue Swep mop, polyester fibre 50 % and viscose 50 %. The mop was moistened in 3 l detergent water 40°C before washing over the area, followed by dry mopping over the same area, but inside the wet area.
  • Sampling
    • Just before, and within 10 min after cleaning.
    • Floor samples were not taken from visibly stained areas.
    • ATP samples were taken first, then the microbiological samples.
    • Samples were taken at three different positions before and after cleaning.

Results

  • Organic soil removal
    • Presence of organic materials varied between rooms and days.
    • All methods reduced organic material on the floors, but wet and moist mopping seemed to be the most effective.
    • Cleaning reduced organic material to 5-36 % of the level present before cleaning, depending upon mopping method.
  • Removal of microbes
    • Bacteria on the floor showed a large day-to-day variation.
    • Before cleaning, the mean bacterial count was 83 cfu/20 cm2.
    • A mean of around 60 % of cfu was removed by dry, moist and wet mopping, but only 30 % by the spray mopping.
    • All four methods reduced the bacteria on the floor from 60-100 to 30-60 cfu/20 cm2.
  • Mopping effect on cfu/m3 air
    • No significant difference between the four mopping methods concerning effect on bacteria in air but after mopping, the mean numbers of cfu/m3 air increased for all four methods.