Post on 29-Jan-2016
transcript
The Use of UV Light in Infection Control. The Use of UV Light in Infection Control.
John BurrowsJohn BurrowsManaging Director Managing Director
Pathogen Solutions Ltd
Host (patient)
Route of transmission
THE SPREAD OF INFECTION The spread of infection within health care requires three elements:
sourcesource
ROUTES OF TRANSMISSION• Contact • Droplet and Airborne • Infected food or drink • Vectors
The ELECTROMAGNETIC SPECTRUM
– UV-A: 315 to 400 nanometres – UV-B: 280 to 315 nanometres – UV-C: 100 to 280 nanometres - germicidal
• UVc is the shortest wavelength and is a danger to the skin and eyes if over exposed
• The effective band width for germicidal function is 253.7 nm
Downes A., and Blunt T. P., “Researches on the Effect of Light upon Bacteria and Other Organisms”, Proceedings of the Royal Society of Medicine, 26; 488, 1877
In 1877 Downes & Blunt investigated the effect of sunlight on bacteria.
What Downes and Blunt had discovered was the germicidal effect of the ultraviolet light
Discovery
Terrence P. Blunt This led to the
• Neils Finsen’s, “Finsen Lamp”• Sunlight Therapy
anthrax, cholera, dysentery, the plague and tuberculosis
Ultraviolet Germicidal Irradiation UVGI
Ultraviolet Germicidal Irradiation UVGI
How is UV commonly applied
• In-duct irradiation of heating and ventilation systems
• Stand alone retro fit devices
FAN®
0%
20%
40%
60%
80%
100%
0 1 2 3 4 5 6 7 8 9 10centimetres
UVc has poor propagation. .
However there is a problem
Within 5cm, of the light source 75% of the power has been dissipated!
x
5
5cm
14,400 W cm-2 3,750W cm-2
Power Dissipation
3,750W / cm2 x 4
= 15,000W / cm2
5cm
The Solution
01
23
45
67
89
1001
23
45
67
89
100
3000
6000
9000
12000
15000
18000
uWatts/cm2
x axisy axis
Power Distribution
15000-18000
12000-15000
9000-12000
Power Distribution
Cross Section through the machine
20 40 60 80 100 120 140 160 180 200 220
S1
S2
S3
S4
S5S6S7S8S9S10S11
0
5000
10000
15000
20000
25000
Four lamps array
Single Lamp
airspeed = 0.3m /sec L = 450mm t = 1.5s power = 15,000W / cm/ cm22
•Therefore
Minimum energy = Minimum energy = 22,50022,500 W sec / cmW sec / cm22
Some simple maths:
Exposure Time
[energy = power x time][energy = power x time]
Energy Requirements to Destroy Specific Micro-organisms
Medixair produces 22,500µW s. cm-2
Bacteria BacteriaAgrobacterium tumefaciens 4,200 Mycobacterrium tuberculosis 6,200 Bacillus anthracis 4,500 Neisseria catarrhalis 4,400 Bacillus aegaterium (Spore) 9,070 Phytomonas tumefaciens 4,400 Bacillus aegaterium 3,750 Proteus vulgaris 3,000 Bacillus subtilis (spore) 12,000 Pseudomonas aeruginosa 5,500 Bacillus subtilis 7,100 Pseudomonas fluorescens 3,500 Bacillus paratyphosus 3,200 Salmonella enteritidis 7,600 Bacillus enteritidis 4,000 Salmonella paratyphi 6,100 Corynebacterium diphteriae 3,750 Salmonella typhimurium 8,000 Clostridium tetani 4,900 Samonella typhosa 6,000 Clostridium botulinium 12,000 Sarcina lutea 19,700 Dysentery bacilli 2,200 Serratia marcesens 2,420 Eberthella typhosa 2,140 Shighella dysenteriae 4,200 E. coli 5,400 Shigella paradysenterea 1,680 Leptospira spp (Infectious Jaundice) 3,000 Shigella flexneri 1,700 Legionella pneumophila 2,040 Shigella sonnei 2,100 Legionella bozemanii 1,800 Spirillium rubsum 4,400 Legionella bumoffii 3,000 Staphylococcus albus 1,840 Legionella gormanii 2,500 Staphylococcus aureus 2,600 Legionella micdadei 1,500 Streptococcus haemolyticus(A) 6,700 Legionella longbeachae 1,500 Streptococcus haemolyticus(D) 9,500 Listeria monocytogenes 3,400 Streptococcus lactis 6,150 Micrococcus candidus 6,050 Streptococcus viridans 2,000 Micrococcus sphaeroides 10,000 Streptococcus pyrogenes 2,160
Streptococcus salivarius 2,000
µW s. cm-2 µW s. cm-2
Test 1: Bacteria TestingBacteria TestingSpore Precipitation rate & UVc Treated Spore Survival curve ( B.megaterium)
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
1.0E+08
0 1 2 3 4 5 6 7 8
Medicare Processing time in Hours
Lo
g/c
fu/m
2 su
rviv
ors
Spore Precipitation rate & UVc Treated Spore Survival curve ( B globigii)
1.00E+00
1.00E+01
1.00E+02
1.00E+03
1.00E+04
1.00E+05
1.00E+06
1.00E+07
1.00E+08
0 1 2 3 4 5 6 7 8
Medicaire Processing time in Hours
Lo
g/c
fu/m
2 s
urv
ivo
rs
Spore Precipitation rate & UVc Treated Spore Survival curve ( B.subtilis)
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
1.0E+08
0 1 2 3 4 5 6 7 8
Medicare Processing time in Hours
Log/
cfu/
m2
surv
ivor
s
Uvc Dosing cfu/ m3 recovered NO UVc
“In the lab Medixair demonstrated between 6.0 to 7.0 log reductions against the challenge of three strains of bacterium”
1. 0 Organisms Employed ;Bacillus megaterium NCTC 10342Bacillus globigii ATCC 49822Bacillus subtilis ATCC 19659Bacillus cereus NCTC 2599Salmonella typhi murium NCTC 74Ecoli 0157 H7 NCTC 12079
(ATTENUATED STRAIN: EX PUBLIC HEALTH SERVICE CULTURE)Staphylococcus aureus NCTC 8532Aspergillus niger NCPF 2275
Precipitation Only No UVPrecipitation Only No UV
Energy Requirements to Destroy Specific Micro-organisms
Virus
Adenovirus 3 1,500 Bacteriophage (E. Coli virus) 3,000 Coxsackie virus A9 12,000 Coxsackie virus B1 15,500 Echovirus 1 11,000 Echovirus 2 12,000 Hepatitis A 11,000 Influenza 3,400 Poliovirus 12,000 Reovirus 1 15,400 Rotavirus SA11 7,800
Medixair produces 22,500µW s. cm-2
µW s. cm-2
Test 4Test 4 Viral Particle TestingViral Particle Testing
our data does demonstrate with a high degree of significance that the Medixair UVc air sterilisation unit was effective in reducing continuous doses of each virus over a 4.5-hour period. The corrected log inactivation data per 30 minute cycle in table 5 clearly illustrates a high and sustained level of inactivation for each viral target, with the range being measured at between 4.4 to 6.1 log reductions of challenge per 30 minutes with dosing at rates described above.
Table (A) below details relating to the virus particles employed during this series of the experiments.
VirusNucleic
acidFamily
E.coli T4 Phage ds DNA Myoviridae (T4 like phages)
FCoVA "+" ss RNA Nidovirales (genus corona virus)
Saccaharomycesvirus ScV-L-BC
ds RNA Totiviridae
Vibrio phage fs1 ss DNA Inovirdiae
Graph2 Reduction of Virus particles over 4.5 hours w ith UVc
treatment and w ith replacement
1
100
10000
1E+06
1E+08
1E+10
1E+12
1E+14
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
A
B
Inactivation of T4 Phage -Continuous Challenge
Virus
Measured continuous mean log reduction of virus
particles
E.coli T4 Phage 6.1
FCoVA 4.4
Saccaharomyces virus ScV-L-BC 4.7
Vibrio phage fs1 5.3
Upstream
Down stream
• Ease of Use
• Quiet operation <33dB
• Zero Ozone Generation
• Safety for patients and healthcare workers
Important Design Criteria
Sustainable Solution
The EvidenceThe Evidence
UV Room
Control Room
Cross Over
UV Removed
UV Installed
No
of p
ositi
ve s
wab
sN
o of
pos
itive
sw
abs
Data sets
Data sets
MRSA Side Wards - known hotspotsNorth London NHS Hospital
Curtain 22%
Bed 61%
Floor 74%
Light 30%
Curtain 9%
Bed 9%
Floor 26%
Light 9%
UV-ROOMUV-ROOM CONTROL- ROOM
Patient 0%
Patient 47%
MRSA Side Wards - known hotspotsNorth London NHS Hospital
UVc installation
Clostridium difficile - surveillance data 2006 -2008
Orthopaedic Trauma Ward – North London NHS Hospital
Intervention in the chain of Intervention in the chain of infectioninfection
A proven scienceA proven science
Easy to installEasy to install
QuietQuiet
SafeSafe
SustainableSustainable
Thank you for ListeningThank you for Listening
.comJohnBurrows@