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@