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Portuguese Ministry of Economy
National Institute of Engineering and Industrial Technology
Industrial Microbiologic Laboratory
Report (ref. 566/01)

THE EFFICIENCY OF AN AIR STERILIZER MANUFACTURED UNDER U.S. PATENT 5874050 IN REDUCING THE AIRBORNE MICROBIAL LEVEL IN PARTIAL CLOSED ROOM AT D. ESTEFANIA HOSPITAL, LISBON

OBJECTIVES
The main objective of this report is to verify the efficiency of an air sterilizer model in reducing airborne bacteria and fungus levels in partially closed areas. This report verified the airborne microbial levels in one admission room at the D. Estefania Hospital during a 57 days period when the air sterilizer manufactured under license of US Patent 5874050 was plugged in.

METHODOLOGY
The chosen room for the test was one admission room (beds 7,8,9 and 10) of the Obstetric Department.
Initially during 35 days just one device was placed. Device was plugged in on August 6, 2001 after collecting that day air samples

 

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(samples prior to the action of the devices). Air samples were taken on following days: August 31 and September 3,7 and 10. On September 10th one additional device was plugged in the same room. Under those new circumstances the test report lasted for another 22 days. On October 2nd the last air sample was taken so as to evaluate the effect of 2 devices (in the same room). An air sampler (Merck MAS-100) was used for each air sample, one air sample being taken per day. 100 l if air were taken for each air sample.
The airborne microorganism count was made in 9cm diameter Petri dishes.

Culture means utilized for room airborne microbial count

Fungus: Malt Extract Agar (MEA) Difco
Bacteria: Trypona Soya Agar (TSA) Oxoid

Incubation Conditions:

Fungus: 7 days at 25ºC
Bacteria: 3 days at 30ºC

Results for bacteria and fungus are expressed in u.f.c. (formatting colony units)

 

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RESULTS

Fungus and bactéria obtained results are stated in the chart in Fig. 1

(Chart) Obstetrics – Admission room
bacteria
fungus
Aug 5 Aug 31 Sep 3 Sept 7 Sep 10 Oct 2
collection days

FIGURE 1. – Effect of an air sterilizer manufactured under license of US patent 5874050 in maintaining airborne bacteria and fungus levels in one admission room with beds 7,8,9 and 10 (Obstetrics). First device was connected on August 6th and second on September 10th, both (plugged in) before those day air samples were collected.

It is verified by observing Figure 1 above that device had influence in the reduction of bacteria and fungus levels in the ambiance of tested room. With one device was clear the reduction

 

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of bacteria and fungus until September 3, remaining quite constant in the next 2 air samples. The reduction capacity seems to be improved after the installation of one second device in the (tested) room (in September 10), although just one additional sample reading does not allows us to obtain one safe conclusion.

Lisbon, October 30, 2001

Responsible for the Micology Sector Director for the L.M.I.

(legible signature) (legible signature)

Pablo Tavares Pereira Jose Carlos Roseiro