Journal
of Hospital
Injection
The effect
(1991)
18, 191-200
of disinfectants
S. Mehtar,
A. Tsakris,
on perforated D. Castro*
gloves
and F. Mayet
Department of Microbiology, North Middlesex Hospital, London N18 1QX and *East Avenue Medical Centre, Manilla, Philippines Accepted for publication
11 April 1991
Summary: Three types of gloves, ‘Biogel’, ‘Regent Dispo Surgical’ gloves and Ansell gammex were perforated, and contaminated with Escherichia coli or Pseudomonas aeruginosa as test organisms applied either to the hand or the glove surface. The glove surface was decontaminated with alcoholic chlorhexidine (‘Hibisol’), methylated spirit, or soap and water. The experiments were performed in triplicate on three separate days. The experiments were designed to study the ability of the three disinfection methods to reduce the bacterial count of 10” colony forming units (cfu) ml-’ (applied to perforated gloves or hands) sufficiently to permit the re-use of such gloves for non-sterile ward procedures. The best method of disinfection was using alcoholic chlorhexidine which not only reduced glove surface carriage but also reduced transfer of bacteria to the hands through the perforation in the gloves. Soap and water was the least effective. Escherichia coli was more easily removed than P. aeruginosa. We recommend that non-sterile ward procedures may be carried out even after gloves have been perforated provided alcoholic chlorhexidine is used between each procedure to reduce cross-infection between patients. Keywords:
Hands;
gloves;
perforation;
disinfection;
cross-infection.
Introduction Hands are a major source of cross-infection in hospitals’ and the use of gloves as a protective barrier between patient and hospital staff has been standard practice since Lowbury et a1.2 demonstrated carriage rates of transient bacteria. Recently, due to the high cost of using sterile gloves, there have been suggestions that in dental practice non-sterile gloves may be re-used after decontamination with povidone-iodine,3 or chlorhexidine in 70% isopropyl alcohol (‘Hibisol’, ICI Pharmaceuticals). Soap and water has been a useful means of reducing contamination of the hands4 and hand washing after removal of gloves’ has been recommended. However, there has been little in the literature to advise on the decontamination of gloves for use in non-sterile procedures in hospital practice, particularly where there is a shortage of gloves and the procedure is not possible for financial reasons. In some developing countries, surgical gloves are tested for perforations by a leak test (either manual or mechanical), and those found to be intact are 019556701/91;070191
+ 10 SO3 OO!O
:c‘ 1991 The Hospital
191
Infectmn
Socmy
192
S. Mehtar
et al.
recycled after being autoclaved, while the perforated gloves are discarded. An insufficient supply of gloves for use in hospitals, and the lack of handwashing facilities, leads to non-sterile ward procedures being carried out without proper hand hygiene due to the fact that the water supply may be contaminated. The basis for this study was to examine the possibility of reusing perforated gloves for non-sterile ward procedures by decontaminating the gloves between patients and examining the effect of different disinfection methods that might be available in developing countries. The study was designed as follows: (a) to establish the number of times a particular glove type may be re-cycled before perforation occurred; (b) once perforation had occurred, to identify an effective method of disinfection for safe use in ward procedures.
Material
and methods
Two volunteers, one male and one female, participated in each set of experiments which were performed in triplicate on three separate days and which tested three glove types (A, B, C). The test organisms (either E. coli or P. aeruginosa) were applied either to the hands or to the glove surface. Gloves. Three types of gloves were compared for durability and residual bacteria counts on fingers following disinfection. (A) ‘Regent Biogel’ (reinforced non-starch gloves; London Rubber Co.); (B) ‘Regent Dispo’ surgical gloves (rough starched gloves; London Rubber Co.); (C) ‘Ansell gammex’ (rough starched gloves; Smith and Nephew.) Organisms. lo7 colony forming units (cfu) ml-’ of E. coli NCTC 10418, or P. aeruginosa (clinical isolate) were used as test organisms and applied to either the finger tips or the surface of the gloves. Media. Horse blood agar (Oxoid) was used for the baseline (pre-application) experiments. MacConkey or Blood agar (Oxoid) was used for finger-tip imprints and recovery bacterial counts of the test organisms. In addition, a nutrient agar plate incorporating Tween 80 (3%) plus azolectin (0.3%) was used to neutralize chlorhexidine and was compared with the standard set of plates. Disinfection method. Three methods of disinfection were considered: (a) 0.5% w/v chl or h exi ‘deme gluconate in 70% w/w isopropyl alcohol (‘Hibisol’, ICI). (b) 70% methyl alcohol (methylated spirit, BP). (c) liquid soap and water. These were chosen for ease of availability in most countries. Five ml of alcoholic chlorhexidine or methyl alcohol was dispensed on to the palm of the hand with a graduated pipette and rubbed into the finger tips of the glove or hand until dry. Two ml of soap was dispensed from a standard dispenser on to wet hands or gloves and rubbed vigorously
Disinfection
of perforated
(particularly the finger tips) for one minute, with a paper towel.
gloves
193
rinsed off and dried thoroughly
Experiments
1. Glove durability. A preliminary set of experiments were carried out to establish durability of the glove by reusing the same pair of gloves to carry out prescribed activities for 10 minutes. This consisted of touching various surfaces, handling and washing of sharp instruments in a bucket of water, and handling equipment. At the end of each set of experiments, the gloved hands were rinsed and the gloves were removed and dropped in a bowl of water to be washed. After filling the gloves with air they were resubmerged in a clean bowl of water to look for leaks, indicated by escaping air bubbles. The gloves were then washed and inverted to dry for use the following day. When perforation occurred, a glove pair was replaced by the same glove-type until five pairs of gloves of one type had been damaged or perforated. The number of replacements required for the other types of gloves under the same conditions was noted. 2. Bacterial counts. Fingertips (from the tip to the first phalangeal joint) were imprinted on the agar plates for 30 s and the bacterial colony counts were recorded. The mean colony counts from three experiments were calculated and were analysed statistically. (a) Baseline counts of residual flora from the hands of the volunteers were established while carrying out the glove durability studies. These were performed in triplicate on three separate days. Each step described below coincides with the number on the graph in Figure 1. (1) Hands were washed with soap and water and dried thoroughly and fingertip imprints were taken. (2) Gloves were worn and fingertip imprints taken. (3) Prescribed activity (as under durability studies) was carried out. Imprints were taken. (4) The gloves were decontaminated with alcoholic chlorhexidine and rubbed in until dry. Imprints were taken. (5) A further 10 min of ‘work’ was carried out and imprints taken. The gloved hands were washed in a bowl of detergent (to simulate practice in certain countries), rinsed thoroughly and dried. (6) Finger impressions were taken after removal of the gloves. Organisms isolated from the finger imprints on blood agar were counted and identified. (b) Contamination experiments. Either the fingertips or glove tips were contaminated with the test organism. The gloves were perforated with an 18 gauge hypodermic needle to create a tear which was visible. The perforations were not designed to be standard but each finger of the glove was perforated. The method outlined below designates the sample number of each fingerprint impression taken after each step of the experiment and corresponds with the numbers on Figures 2a and 2b.
S. Mehtar
et al.
B I
r
7-c ,’ A 70-v
tJ’
y 60-’ ‘; sp 50-/
: \
II I: : .:’
: !,
4
i
II:: .
3
Tj
.
:
30-’
& u 2 20-’ I o-’
”
0’
I Hand
Figure
1. Baseline
counts
z
3
Gloves
1st work
of residual
7
4
Hibisol
3
2nd work
flora at each stage of the study
b
Hand
(see text for details).
Organisms on hands (Figure 2). Hands were washed and dried thoroughly. (1) Hands were contaminated with the test organism (10’ cfu ml-‘), and imprints taken. (2) Gloves were worn, then imprints were taken. (3) Gloves were then perforated; imprints were taken. (4) Decontamination was carried out according to protocol, and imprints taken. (5) Gloves were then removed and imprints taken. Figures 2a and 2b relate to E. coli and P. aeruginosa respectively. Organisms on gloves (Figure 3). (1) Hands were thoroughly washed and dried and fingertip imprints taken. (2) Gloves were worn and finger-tip imprints taken. (3) Either E. coli or P. aeruginosa (10’ cfu ml-’ were applied to the tip of the gloves and rubbed in for 30 s. Imprints were taken.
on hands/Hibisol
100 8”:
Paeroo,nosa
on hands/Alcohol
IO
20
30
40
70 60 50
B
7
2
3
4
5
m
P oeruq,noso
I2
3
ond wotei
5
Key: 1, Hands, removed. Glove
4
and water
on hands/Soap
Imprints
E co// on hands/Soap
of hands with (a) E. coli, (b) P. aeruginosa. 4, decontamination; 5, hands after gloves
1
__
100 8”: -___-.
Figure 2. Bacterial counts after contamination test organism 10’ cfu; 2, gloves; 3, perforation; A; ----, B; ., C. types: ~,
‘OOO?r?--
P aerug,noso
IO
IO
(b)
20
20
9
30
30
2&
E 70 60 50 40
loo0
2 : g
Imprints
E co11 on hands/Alcohol
‘% 80
1000
70 60 50 40
I2345 Imprints
E co/i on hands/Hlbisol
100 .,? 0 8’0”
lOOOfT\
(a)
P oeruginoso
56
Imprints
on gloves/Hiblsol ,,4
A
34 Imprints
7
I
I2
Poerog,noso
1234567
3456 Imprints
on gloves/Alcohol
Imprints
7
IO
IO B
20
20
I
2
Paeruoinoso
123456
3 4 Imprints
5
j 7
c
1
6
7
and water
and water
an gloves/Soar,
Imprints
E CO/I on gloves/soap
Figure 3. Bacterial counts after contamination of gloves with (a) E. coli, (b) P. aeruginosa. Key: 1, Hands; 2, 1; 5, perforation 10’ cfu; 6 decontamination 2; 7, hands after gloves; 3, 10’ cfu test organism; 4, decontamination gloves removed. Glove types: ~, A; ----, B; . . . ., C.
70 60 50 40
100 200
lOOOf,
ib)
12
30
30
,’
2 50 40
50 40
:,8
IO
1000
Disinfection
of perforated
gloves
197
(4) Glove surfaces were decontaminated with either ‘Hibisol’, Methyl alcohol or soap and water. Then imprints were taken. (5) Gloves were perforated and imprints taken. (6) Gloves were recontaminated with the test organism ( 107 cfu ml-‘). Decontamination was carried out for the second time and imprints taken. (7) Gloves were then removed and imprints taken. Figures 3a and 3b relate to E. coli and P. aeruginosa respectively. Only counts of the test organism on MacConkey Agar (and Tween 80 agar) were recorded, and a mean bacterial count for each step of the three experiments was taken as the end result. Statistical analysis was carried out using the Student t-test (a) for each set of experiments using the same glove type disinfected by the three methods mentioned above, and (b) for each disinfectant individually. Results
The results are presented according to whether the organism had been applied either to hands (Figure 2) or gloves (Figure 3). The solid lines represent superimposed results of all three gloves. Glove durability ‘Regent surgical’ gloves and ‘Biogel’ were found to be the most resilient and capable of withstanding manual activity; Ansell gloves were the least capable of doing so. Baseline counts A significant reduction from 100-l 50 cfu to 10-25 cfu was noted in the fingertip print baseline counts after wearing gloves (Figure 1,2). Following the use of alcoholic chlorhexidine no growth was obtained except for 1 cfu in Ansell gloves (Figure 1,4). The reacquisition of bacteria on to the glove surface following the second exposure to ‘work’ was also reduced significantly after use of alcoholic chlorhexidine compared with the first time (Figure 1,s). There was no difference in the fingertip bacterial counts found before and after the experiment for each of the glove types. Contamination experiments (1) E. coli on hands (Figure 2a). All three types of gloves contained the initial inoculum of lo7 cfu (Figure 2a,2). After perforation O-7 cfu were transferred onto agar. Following application of alcoholic chlorhexidine and methyl alcohol, no growth was obtained, but with soap and water 30-70 cfu were recovered from the glove surfaces. After removal of the gloves the lowest counts on the hands were found with alcoholic chlorhexidine (O-3 cfu) (F’g1 ure 2a,5) and the highest with soap and water (8&300 cfu) (Figure 2a,.5) (P
of Hospital
Injection
The effect
(1991)
18, 191-200
of disinfectants
S. Mehtar,
A. Tsakris,
on perforated D. Castro*
gloves
and F. Mayet
Department of Microbiology, North Middlesex Hospital, London N18 1QX and *East Avenue Medical Centre, Manilla, Philippines Accepted for publication
11 April 1991
Summary: Three types of gloves, ‘Biogel’, ‘Regent Dispo Surgical’ gloves and Ansell gammex were perforated, and contaminated with Escherichia coli or Pseudomonas aeruginosa as test organisms applied either to the hand or the glove surface. The glove surface was decontaminated with alcoholic chlorhexidine (‘Hibisol’), methylated spirit, or soap and water. The experiments were performed in triplicate on three separate days. The experiments were designed to study the ability of the three disinfection methods to reduce the bacterial count of 10” colony forming units (cfu) ml-’ (applied to perforated gloves or hands) sufficiently to permit the re-use of such gloves for non-sterile ward procedures. The best method of disinfection was using alcoholic chlorhexidine which not only reduced glove surface carriage but also reduced transfer of bacteria to the hands through the perforation in the gloves. Soap and water was the least effective. Escherichia coli was more easily removed than P. aeruginosa. We recommend that non-sterile ward procedures may be carried out even after gloves have been perforated provided alcoholic chlorhexidine is used between each procedure to reduce cross-infection between patients. Keywords:
Hands;
gloves;
perforation;
disinfection;
cross-infection.
Introduction Hands are a major source of cross-infection in hospitals’ and the use of gloves as a protective barrier between patient and hospital staff has been standard practice since Lowbury et a1.2 demonstrated carriage rates of transient bacteria. Recently, due to the high cost of using sterile gloves, there have been suggestions that in dental practice non-sterile gloves may be re-used after decontamination with povidone-iodine,3 or chlorhexidine in 70% isopropyl alcohol (‘Hibisol’, ICI Pharmaceuticals). Soap and water has been a useful means of reducing contamination of the hands4 and hand washing after removal of gloves’ has been recommended. However, there has been little in the literature to advise on the decontamination of gloves for use in non-sterile procedures in hospital practice, particularly where there is a shortage of gloves and the procedure is not possible for financial reasons. In some developing countries, surgical gloves are tested for perforations by a leak test (either manual or mechanical), and those found to be intact are 019556701/91;070191
+ 10 SO3 OO!O
:c‘ 1991 The Hospital
191
Infectmn
Socmy
192
S. Mehtar
et al.
recycled after being autoclaved, while the perforated gloves are discarded. An insufficient supply of gloves for use in hospitals, and the lack of handwashing facilities, leads to non-sterile ward procedures being carried out without proper hand hygiene due to the fact that the water supply may be contaminated. The basis for this study was to examine the possibility of reusing perforated gloves for non-sterile ward procedures by decontaminating the gloves between patients and examining the effect of different disinfection methods that might be available in developing countries. The study was designed as follows: (a) to establish the number of times a particular glove type may be re-cycled before perforation occurred; (b) once perforation had occurred, to identify an effective method of disinfection for safe use in ward procedures.
Material
and methods
Two volunteers, one male and one female, participated in each set of experiments which were performed in triplicate on three separate days and which tested three glove types (A, B, C). The test organisms (either E. coli or P. aeruginosa) were applied either to the hands or to the glove surface. Gloves. Three types of gloves were compared for durability and residual bacteria counts on fingers following disinfection. (A) ‘Regent Biogel’ (reinforced non-starch gloves; London Rubber Co.); (B) ‘Regent Dispo’ surgical gloves (rough starched gloves; London Rubber Co.); (C) ‘Ansell gammex’ (rough starched gloves; Smith and Nephew.) Organisms. lo7 colony forming units (cfu) ml-’ of E. coli NCTC 10418, or P. aeruginosa (clinical isolate) were used as test organisms and applied to either the finger tips or the surface of the gloves. Media. Horse blood agar (Oxoid) was used for the baseline (pre-application) experiments. MacConkey or Blood agar (Oxoid) was used for finger-tip imprints and recovery bacterial counts of the test organisms. In addition, a nutrient agar plate incorporating Tween 80 (3%) plus azolectin (0.3%) was used to neutralize chlorhexidine and was compared with the standard set of plates. Disinfection method. Three methods of disinfection were considered: (a) 0.5% w/v chl or h exi ‘deme gluconate in 70% w/w isopropyl alcohol (‘Hibisol’, ICI). (b) 70% methyl alcohol (methylated spirit, BP). (c) liquid soap and water. These were chosen for ease of availability in most countries. Five ml of alcoholic chlorhexidine or methyl alcohol was dispensed on to the palm of the hand with a graduated pipette and rubbed into the finger tips of the glove or hand until dry. Two ml of soap was dispensed from a standard dispenser on to wet hands or gloves and rubbed vigorously
Disinfection
of perforated
(particularly the finger tips) for one minute, with a paper towel.
gloves
193
rinsed off and dried thoroughly
Experiments
1. Glove durability. A preliminary set of experiments were carried out to establish durability of the glove by reusing the same pair of gloves to carry out prescribed activities for 10 minutes. This consisted of touching various surfaces, handling and washing of sharp instruments in a bucket of water, and handling equipment. At the end of each set of experiments, the gloved hands were rinsed and the gloves were removed and dropped in a bowl of water to be washed. After filling the gloves with air they were resubmerged in a clean bowl of water to look for leaks, indicated by escaping air bubbles. The gloves were then washed and inverted to dry for use the following day. When perforation occurred, a glove pair was replaced by the same glove-type until five pairs of gloves of one type had been damaged or perforated. The number of replacements required for the other types of gloves under the same conditions was noted. 2. Bacterial counts. Fingertips (from the tip to the first phalangeal joint) were imprinted on the agar plates for 30 s and the bacterial colony counts were recorded. The mean colony counts from three experiments were calculated and were analysed statistically. (a) Baseline counts of residual flora from the hands of the volunteers were established while carrying out the glove durability studies. These were performed in triplicate on three separate days. Each step described below coincides with the number on the graph in Figure 1. (1) Hands were washed with soap and water and dried thoroughly and fingertip imprints were taken. (2) Gloves were worn and fingertip imprints taken. (3) Prescribed activity (as under durability studies) was carried out. Imprints were taken. (4) The gloves were decontaminated with alcoholic chlorhexidine and rubbed in until dry. Imprints were taken. (5) A further 10 min of ‘work’ was carried out and imprints taken. The gloved hands were washed in a bowl of detergent (to simulate practice in certain countries), rinsed thoroughly and dried. (6) Finger impressions were taken after removal of the gloves. Organisms isolated from the finger imprints on blood agar were counted and identified. (b) Contamination experiments. Either the fingertips or glove tips were contaminated with the test organism. The gloves were perforated with an 18 gauge hypodermic needle to create a tear which was visible. The perforations were not designed to be standard but each finger of the glove was perforated. The method outlined below designates the sample number of each fingerprint impression taken after each step of the experiment and corresponds with the numbers on Figures 2a and 2b.
S. Mehtar
et al.
B I
r
7-c ,’ A 70-v
tJ’
y 60-’ ‘; sp 50-/
: \
II I: : .:’
: !,
4
i
II:: .
3
Tj
.
:
30-’
& u 2 20-’ I o-’
”
0’
I Hand
Figure
1. Baseline
counts
z
3
Gloves
1st work
of residual
7
4
Hibisol
3
2nd work
flora at each stage of the study
b
Hand
(see text for details).
Organisms on hands (Figure 2). Hands were washed and dried thoroughly. (1) Hands were contaminated with the test organism (10’ cfu ml-‘), and imprints taken. (2) Gloves were worn, then imprints were taken. (3) Gloves were then perforated; imprints were taken. (4) Decontamination was carried out according to protocol, and imprints taken. (5) Gloves were then removed and imprints taken. Figures 2a and 2b relate to E. coli and P. aeruginosa respectively. Organisms on gloves (Figure 3). (1) Hands were thoroughly washed and dried and fingertip imprints taken. (2) Gloves were worn and finger-tip imprints taken. (3) Either E. coli or P. aeruginosa (10’ cfu ml-’ were applied to the tip of the gloves and rubbed in for 30 s. Imprints were taken.
on hands/Hibisol
100 8”:
Paeroo,nosa
on hands/Alcohol
IO
20
30
40
70 60 50
B
7
2
3
4
5
m
P oeruq,noso
I2
3
ond wotei
5
Key: 1, Hands, removed. Glove
4
and water
on hands/Soap
Imprints
E co// on hands/Soap
of hands with (a) E. coli, (b) P. aeruginosa. 4, decontamination; 5, hands after gloves
1
__
100 8”: -___-.
Figure 2. Bacterial counts after contamination test organism 10’ cfu; 2, gloves; 3, perforation; A; ----, B; ., C. types: ~,
‘OOO?r?--
P aerug,noso
IO
IO
(b)
20
20
9
30
30
2&
E 70 60 50 40
loo0
2 : g
Imprints
E co11 on hands/Alcohol
‘% 80
1000
70 60 50 40
I2345 Imprints
E co/i on hands/Hlbisol
100 .,? 0 8’0”
lOOOfT\
(a)
P oeruginoso
56
Imprints
on gloves/Hiblsol ,,4
A
34 Imprints
7
I
I2
Poerog,noso
1234567
3456 Imprints
on gloves/Alcohol
Imprints
7
IO
IO B
20
20
I
2
Paeruoinoso
123456
3 4 Imprints
5
j 7
c
1
6
7
and water
and water
an gloves/Soar,
Imprints
E CO/I on gloves/soap
Figure 3. Bacterial counts after contamination of gloves with (a) E. coli, (b) P. aeruginosa. Key: 1, Hands; 2, 1; 5, perforation 10’ cfu; 6 decontamination 2; 7, hands after gloves; 3, 10’ cfu test organism; 4, decontamination gloves removed. Glove types: ~, A; ----, B; . . . ., C.
70 60 50 40
100 200
lOOOf,
ib)
12
30
30
,’
2 50 40
50 40
:,8
IO
1000
Disinfection
of perforated
gloves
197
(4) Glove surfaces were decontaminated with either ‘Hibisol’, Methyl alcohol or soap and water. Then imprints were taken. (5) Gloves were perforated and imprints taken. (6) Gloves were recontaminated with the test organism ( 107 cfu ml-‘). Decontamination was carried out for the second time and imprints taken. (7) Gloves were then removed and imprints taken. Figures 3a and 3b relate to E. coli and P. aeruginosa respectively. Only counts of the test organism on MacConkey Agar (and Tween 80 agar) were recorded, and a mean bacterial count for each step of the three experiments was taken as the end result. Statistical analysis was carried out using the Student t-test (a) for each set of experiments using the same glove type disinfected by the three methods mentioned above, and (b) for each disinfectant individually. Results
The results are presented according to whether the organism had been applied either to hands (Figure 2) or gloves (Figure 3). The solid lines represent superimposed results of all three gloves. Glove durability ‘Regent surgical’ gloves and ‘Biogel’ were found to be the most resilient and capable of withstanding manual activity; Ansell gloves were the least capable of doing so. Baseline counts A significant reduction from 100-l 50 cfu to 10-25 cfu was noted in the fingertip print baseline counts after wearing gloves (Figure 1,2). Following the use of alcoholic chlorhexidine no growth was obtained except for 1 cfu in Ansell gloves (Figure 1,4). The reacquisition of bacteria on to the glove surface following the second exposure to ‘work’ was also reduced significantly after use of alcoholic chlorhexidine compared with the first time (Figure 1,s). There was no difference in the fingertip bacterial counts found before and after the experiment for each of the glove types. Contamination experiments (1) E. coli on hands (Figure 2a). All three types of gloves contained the initial inoculum of lo7 cfu (Figure 2a,2). After perforation O-7 cfu were transferred onto agar. Following application of alcoholic chlorhexidine and methyl alcohol, no growth was obtained, but with soap and water 30-70 cfu were recovered from the glove surfaces. After removal of the gloves the lowest counts on the hands were found with alcoholic chlorhexidine (O-3 cfu) (F’g1 ure 2a,5) and the highest with soap and water (8&300 cfu) (Figure 2a,.5) (P
