Bacterial Resistance to Microbicides in the Healthcare Environment
Dr. Jean-Yves Maillard, University of Cardiff
Sponsored by Virox Technologies Inc. (www.virox.com)
A Webber Training Teleclass
Hosted by Paul Webber paul@webbertraining.com
www.webbertraining.com
Page 1
Dr Jean
Dr Jean
-
-
Yves Maillard
Yves Maillard
Welsh School of Pharmacy
Welsh School of Pharmacy
Cardiff University, Wales
Cardiff University, Wales
Bacterial resistance to
Bacterial resistance to
microbicides in the
microbicides in the
healthcare environment
healthcare environment
Hosted by Paul Webber
Hosted by Paul Webber
paul@webbertraining.com
paul@webbertraining.com
Sponsored by:
Sponsored by:
Virox Technologies Inc.
Virox Technologies Inc.
www.virox.com
www.virox.com
www.webbertraining.com
•
•
To review the overall mechanisms of bacterial resistance to
To review the overall mechanisms of bacterial resistance to
microbicides
microbicides
•
•
To discuss the factors affecting the antimicrobial efficacy of
To discuss the factors affecting the antimicrobial efficacy of
microbicides and their effects in helping microbial survival and
microbicides and their effects in helping microbial survival and
emerging resistance
emerging resistance
•
•
To discuss the significance of emerging bacterial resistance in
To discuss the significance of emerging bacterial resistance in
the healthcare environment
the healthcare environment
OBJECTIVES
OBJECTIVES
•
•
Resistance: surviving exposure to a biocide concentration that
Resistance: surviving exposure to a biocide concentration that
will
will
kill the rest of the population
kill the rest of the population
Russell. Lancet Infect Dis 2003; 3: 794-803
DEFINITIONS
DEFINITIONS
•
•
Tolerance: inhibited but not killed
Tolerance: inhibited but not killed
Phenotypic tolerance: transient conditions (biofilm)
Phenotypic tolerance: transient conditions (biofilm)
Chapman. Int Biodeter Biodegrad 2003; 51: 133-8
•
•
Resistance in practice
Resistance in practice
: bacterial survival following microbicide
: bacterial survival following microbicide
challenge
challenge
at
at
“
“
in use
in use
”
”
concentration.
concentration.
•
•
Insusceptibility: intrinsic property
Insusceptibility: intrinsic property
•
•
Resistance / tolerance / insusceptibility??
Resistance / tolerance / insusceptibility??
Increased usage of microbicides in various products/surfaces
Increased usage of microbicides in various products/surfaces
BIOCIDE USAGE
BIOCIDE USAGE
Disinfection
Disinfection
-
-
antisepsis
antisepsis
-
-
preservation
preservation
Disinfection
Disinfection
Surface disinfection (non
Surface disinfection (non
-
-
/ semi
/ semi
-
-
/ critical)
/ critical)
High
High
-
-
level disinfection (
level disinfection (
AWDs
AWDs
)
)
Rutala & Weber. Healthcare
Rutala & Weber. Healthcare
Epidemiol
Epidemiol
2004; 39: 702
2004; 39: 702
-
-
9
9
Rutala & Weber. Am J Infect Control 2004; 32: 226
Rutala & Weber. Am J Infect Control 2004; 32: 226
-
-
31
31
Antisepsis
Antisepsis
Alcoholic rubs, etc.
Alcoholic rubs, etc.
Preservation
Preservation
low concentration (cosmetic)
low concentration (cosmetic)
•
•
Incorporation of low concentration of microbicides into products
Incorporation of low concentration of microbicides into products
,
,
surfaces etc.
surfaces etc.
•
•
Plastics
Plastics
•
•
Bed sheets
Bed sheets
-
-
clothing
clothing
•
•
Curtains
Curtains
•
•
Surfaces
Surfaces
•
•
Door handles
Door handles
•
•
Shower rails
Shower rails
•
•
Trolleys
Trolleys
•
•
Laminate flooring
Laminate flooring
-
-
walls
walls
BIOCIDE USAGE
BIOCIDE USAGE
•
•
Effect on microbial microflora in practice not yet determined
Effect on microbial microflora in practice not yet determined
EVIDENCE OF RESISTANCE
EVIDENCE OF RESISTANCE
-
-
in practice
in practice
•
•
Triclosan bath
Triclosan bath
Cookson et al. Lancet 1991; 337: 1548-9
•
•
Triclosan
Triclosan
handwash
handwash
Webster et al. J Paediatr Child health 1994; 30: 59-64
•
•
Chlorhexidine
Chlorhexidine
Nakahara & Kozukue. Sbl Bakt Hyg, I. Abt Orig A 1981; 251: 177-84
•
•
QACs
QACs
Geftic et al. Appl Environ Microbiol 1979; 39: 505-10
•
•
Glutaraldehyde
Glutaraldehyde
Griffiths et al. J Appl Microbiol 1997; 82: 519-26
•
•
Surviving bacteria isolated following biocidal challenges
Surviving bacteria isolated following biocidal challenges
Bacterial Resistance to Microbicides in the Healthcare Environment
Dr. Jean-Yves Maillard, University of Cardiff
Sponsored by Virox Technologies Inc. (www.virox.com)
A Webber Training Teleclass
Hosted by Paul Webber paul@webbertraining.com
www.webbertraining.com
Page 2
0.5
0.5
30
30
Drain area
Drain area
Staphylococcus
Staphylococcus
intermedius
intermedius
0.5
0.5
5
5
Drain area
Drain area
Streptococcus
Streptococcus
mutans
mutans
0.5
0.5
30
30
Endoscope
Endoscope
connectors
connectors
Streptococcus
Streptococcus
sanguinis
sanguinis
0.5
0.5
30
30
Rinse water
Rinse water
Micrococcus
Micrococcus
luteus
luteus
60
60
>60
>60
Rinse water
Rinse water
Bacillus
Bacillus
subtilis
subtilis
(
(
veg
veg
)
)
Hydrogen
Hydrogen
peroxide 7.5%
peroxide 7.5%
Chlorine
Chlorine
dioxide* 2.25%
dioxide* 2.25%
Time (min) to achieve 5 Log
Time (min) to achieve 5 Log
10
10
reduction
reduction
Location
Location
Bacterial strains
Bacterial strains
* formulation
EVIDENCE OF RESISTANCE
EVIDENCE OF RESISTANCE
–
–
in practice
in practice
•
•
Automated washer disinfectors
Automated washer disinfectors
(Martin & Maillard 2006)
EVIDENCE OF RESISTANCE
EVIDENCE OF RESISTANCE
–
–
in practice
in practice
•
•
MRSA in
MRSA in
ITUs
ITUs
–
–
susceptibility to
susceptibility to
NaDCC
NaDCC
(Williams & Maillard 2006)
6.19 (0.11)
6.19 (0.11)
60
60
9518
9518
2.27 (1.74)
2.27 (1.74)
30
30
225
225
Control
Control
6.41 (0.24)
6.41 (0.24)
60
60
6.46 (0.31)
6.46 (0.31)
60
60
5.22 (1.66)
5.22 (1.66)
30
30
350
350
55
55
2.45 (0.84)
2.45 (0.84)
30
30
300
300
47
47
5.93 (0.07)
5.93 (0.07)
120
120
5.26 (2.05)
5.26 (2.05)
60
60
3.46 (1.94)
3.46 (1.94)
60
60
400
400
17
17
2.76 (1.53)
2.76 (1.53)
30
30
325
325
51
51
6.14 (0.09)
6.14 (0.09)
60
60
6.16 (0.33)
6.16 (0.33)
60
60
1.75 (1.76)
1.75 (1.76)
30
30
400
400
52
52
2.01 (0.37)
2.01 (0.37)
30
30
300
300
14
14
6.38 (0.12)
6.38 (0.12)
60
60
5.96 (0.36)
5.96 (0.36)
60
60
5.81 (1.15)
5.81 (1.15)
30
30
400
400
49
49
3.85 (2.19)
3.85 (2.19)
30
30
325
325
13
13
log
log
10
10
R
R
(
(
±
±
SD)
SD)
CT
CT
(sec)
(sec)
MIC
MIC
(
(
ppm
ppm
)
)
log
log
10
10
R
R
(
(
±
±
SD)
SD)
CT
CT
(sec)
(sec)
MIC
MIC
(
(
ppm
ppm
)
)
MRSA
MRSA
MSSA
MSSA
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
REDUCTION OF
REDUCTION OF
UPTAKE
UPTAKE
AND PENETRATION
AND PENETRATION
Reduction in
concentration
REDUCTION OF
REDUCTION OF
ACCUMULATION
ACCUMULATION
Reduction in
concentration
INACTIVATION
INACTIVATION
Reduction in
concentration
(A)
(A)
(B)
(B)
(C)
(C)
OW
OW
CM
CM
PP
PP
CP
CP
CW
CW
(A) IMPERMEABILITY
(A) IMPERMEABILITY
Intrinsic
Intrinsic
- spore coat and cortex
- mycobacteria mycoyl-arabinogalactan
GTA, QACs
GTA, QACs
- outer envelope in Gram-negative
QACs, biguanides, phenolics
QACs, biguanides, phenolics
Acquired
Acquired
- change in lipopolysaccharides / membrane fatty acids
- change in outer membrane protein (porins)
QACs, biguanides
QACs, biguanides
- change in arabinogalactan composition
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
(A) IMPERMEABILITY
(A) IMPERMEABILITY
Intrinsic
Intrinsic
- spore coat and cortex
- mycobacteria mycoyl-arabinogalactan
- outer envelope in Gram-negative
Acquired
Acquired
- change in lipopolysaccharides
- change in outer membrane protein (porins)
- change in arabinogalactan composition
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
Tattwasart et al. J Hosp Infect 1999, 42: 219-29
Tattwasart et al. Int J Antimicrob Agent 2000, 16: 233-8
(A) SURFACE INTERACTIONS
(A) SURFACE INTERACTIONS
Hydrophobicity
Hydrophobicity
QACs
QACs
, CHX
, CHX
Cell surface charge
Cell surface charge
QACs
QACs
Bruinsma et al. J Antimicrob Chemother 2006, 57: 764-6
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
Bacterial Resistance to Microbicides in the Healthcare Environment
Dr. Jean-Yves Maillard, University of Cardiff
Sponsored by Virox Technologies Inc. (www.virox.com)
A Webber Training Teleclass
Hosted by Paul Webber paul@webbertraining.com
www.webbertraining.com
Page 3
(B) EFFLUX (intrinsic or acquired)
(B) EFFLUX (intrinsic or acquired)
- several families of efflux pumps identified
QACs, phenolics, CHX, metallic salts
QACs, phenolics, CHX, metallic salts
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
From Piddock Clin Microbiol rev 2006; 19: 382-402
MATE
MATE
family
family
MFS
MFS
SMR
SMR
family
family
RND family
RND family
ABC
ABC
super family
super family
aminoglycosides
fluoroquinolones
cationics
NorM
QacA
QacC
AcrB
To
lC
LmrA
Na
Na
+
+
H
H
+
+
H
H
+
+
H
H
+
+
ATP
ATP
ADP + Pi
ADP + Pi
acriflavine
BZC
cetrimide
CHX
pentamidine
acriflavine
BZC
cetrimide
multiple
drugs
multiple drugs
AcrA
CM
OM
(C) DEGRADATION (intrinsic or acquired)
(C) DEGRADATION (intrinsic or acquired)
Phenolics, metallic salts, FMA
Phenolics, metallic salts, FMA
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
More than one mechanisms involved
More than one mechanisms involved
10
10
-
-
25
25
10
10
-
-
25
25
25
25
25
25
>1000
>1000
25
25
>1000
>1000
TM4
TM4
10
10
-
-
25
25
10
10
-
-
50
50
25
25
25
25
>1000
>1000
250
250
>1000
>1000
TM3
TM3
10
10
-
-
25
25
10
10
-
-
50
50
25
25
25
25
>1000
>1000
50
50
>1000
>1000
TM2
TM2
10
10
-
-
25
25
10
10
-
-
50
50
25
25
25
25
>1000
>1000
25
25
>1000
>1000
TM1
TM1
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.1
0.1
Standard
Standard
TCS +
TCS +
OVA +
OVA +
EDTA
EDTA
TCS +
TCS +
CCCP +
CCCP +
EDTA
EDTA
TCS +
TCS +
CCCP
CCCP
+OVA
+OVA
TCS +
TCS +
EDTA
EDTA
TCS +
TCS +
OVA
OVA
TCS +
TCS +
CCCP
CCCP
TCS
TCS
alone
alone
E. Coli
E. Coli
ATCC
ATCC
1053
1053
MIC (
MIC (
µ
µ
g
g
/ml)
/ml)
Efflux pump “blockers”: CCCP (carbonyl cyanide m-chlorophenyl hydrazone), OVA
(sodium orthovanadate)
Membrane permeabiliser: EDTA (ethylenediamine tetraacetic acid)
Adaptation
Adaptation
-
-
modification of targets
modification of targets
-
-
overproduction of targets
overproduction of targets
-
-
stress response
stress response
RESPONSE TO BIOCIDE EXPOSURE
RESPONSE TO BIOCIDE EXPOSURE
Mycobacterium
Mycobacterium
terrae
terrae
•
•
Adaptation
Adaptation
-
-
numerous examples of in vitro training
numerous examples of in vitro training
QACs
QACs
, CHX, phenolics, GTA, chlorine
, CHX, phenolics, GTA, chlorine
Gram
Gram
-
-
negative &
negative &
-
-
positive, mycobacteria
positive, mycobacteria
-
-
examples of adaptation
examples of adaptation
in situ
in situ
•
•
Modification of target
Modification of target
-
-
triclosan (
triclosan (
enoyl
enoyl
acyl carrier reductase;
acyl carrier reductase;
fabI
fabI
gene)
gene)
•
•
Eliciting stress response
Eliciting stress response
-
-
induction of
induction of
oxyR
oxyR
and
and
soxRS
soxRS
as a result of hydrogen peroxide
as a result of hydrogen peroxide
exposure
exposure
-
-
followed by expression of efflux pump, reduction in OMP,
followed by expression of efflux pump, reduction in OMP,
changes in fatty acids (?)
changes in fatty acids (?)
RESPONSE TO BIOCIDE EXPOSURE
RESPONSE TO BIOCIDE EXPOSURE
Communication
Communication
-
-
gene transfer
gene transfer
RESPONSE TO BIOCIDE EXPOSURE
RESPONSE TO BIOCIDE EXPOSURE
Mycobacterium
Mycobacterium
terrae
terrae
Bacterial Resistance to Microbicides in the Healthcare Environment
Dr. Jean-Yves Maillard, University of Cardiff
Sponsored by Virox Technologies Inc. (www.virox.com)
A Webber Training Teleclass
Hosted by Paul Webber paul@webbertraining.com
www.webbertraining.com
Page 4
•
•
Extracellular
Extracellular
induction components (
induction components (
EICs
EICs
)
)
Acidification and heat response
Acidification and heat response
Rowburry. Adv Microbiol Physiol 2001; 44: 215-57
S. aureus
S. aureus
pre
pre
-
-
treatment with CHX
treatment with CHX
–
–
Low level resistance (3 fold
Low level resistance (3 fold
increase) in unexposed cultures
increase) in unexposed cultures
Davies & Maillard. J Hosp Infect 2001; 49: 300-1
•
•
Quorum sensing (?)
Quorum sensing (?)
Quorum sensing governing specific gene expression
Quorum sensing governing specific gene expression
Catalase
Catalase
and
and
superoxide
superoxide
dismutase
dismutase
gene expression
gene expression
Hassett et al. Mol Microbiol 1999; 34: 1082-93
RESPONSE TO BIOCIDE EXPOSURE
RESPONSE TO BIOCIDE EXPOSURE
•
•
Increasing transferable resistance (?)
Increasing transferable resistance (?)
•
•
Effect of biocides on gene transfer
Effect of biocides on gene transfer
Pearce et al. J Hosp Infect 1999; 43: 101-7
Increased 1000
Increased 1000
folds
folds
Reduced 2 folds
Reduced 2 folds
0.0001%
0.0001%
Cetrimide
Cetrimide
Reduced 10 folds
Reduced 10 folds
No effect
No effect
0.00005%
0.00005%
Chlorhexidine
Chlorhexidine
Reduced 10 folds
Reduced 10 folds
NT
NT
0.01%
0.01%
NT*
NT*
Increased 2 folds
Increased 2 folds
0.005%
0.005%
Povidone iodine
Povidone iodine
Transduction
Transduction
Conjugation
Conjugation
Increase/decrease in gene transfer by
Increase/decrease in gene transfer by
Concentration
Concentration
Biocide
Biocide
RESPONSE TO BIOCIDE EXPOSURE
RESPONSE TO BIOCIDE EXPOSURE
Selection
Selection
RESPONSE TO BIOCIDE EXPOSURE
RESPONSE TO BIOCIDE EXPOSURE
-
-
POPULATION
POPULATION
Mycobacterium
Mycobacterium
terrae
terrae
•
•
Selection
Selection
-
-
phenolics
phenolics
(triclosan, tea tree oil)
(triclosan, tea tree oil)
-
-
QACs
QACs
-
-
CHX
CHX
-
-
GTA
GTA
-
-
chlorine
chlorine
c) E. coli reference strain
0
2
4
6
8
10
12
14
16
18
20
3
80-
3
89
3
90-
3
99
4
00-
4
09
4
10-
4
19
4
20-
4
29
4
30-
4
39
4
40-
4
49
4
50-
4
59
4
60-
4
69
4
70-
4
79
4
80-
4
89
4
90-
4
99
5
00-
5
09
5
10-
5
19
5
20-
5
29
5
30-
5
39
5
40-
5
49
>5
50
Tim e (minutes)
Nu
m
b
er o
f clo
n
es
No triclosan exposure
Triclosan exposure
d) E. coli mutant strain
0
5
10
15
20
25
38
0-
38
9
39
0-
39
9
40
0-
40
9
41
0-
41
9
42
0-
42
9
43
0-
43
9
44
0-
44
9
45
0-
45
9
46
0-
46
9
47
0-
47
9
48
0-
48
9
49
0-
49
9
50
0-
50
9
51
0-
51
9
52
0-
52
9
53
0-
53
9
54
0-
54
9
>5
50
Time interval (minutes)
N
u
m
b
er
o
f cl
o
n
es
No triclosan exposure
Triclosan exposure
RESPONSE TO BIOCIDE EXPOSURE
RESPONSE TO BIOCIDE EXPOSURE
-
-
POPULATION
POPULATION
•
•
Selection
Selection
-
-
phenolics
phenolics
(triclosan, tea tree oil)
(triclosan, tea tree oil)
-
-
QACs
QACs
-
-
CHX
CHX
-
-
GTA
GTA
-
-
chlorine
chlorine
c) E. coli reference strain
0
2
4
6
8
10
12
14
16
18
20
3
80-
3
89
3
90-
3
99
4
00-
4
09
4
10-
4
19
4
20-
4
29
4
30-
4
39
4
40-
4
49
4
50-
4
59
4
60-
4
69
4
70-
4
79
4
80-
4
89
4
90-
4
99
5
00-
5
09
5
10-
5
19
5
20-
5
29
5
30-
5
39
5
40-
5
49
>5
50
Tim e (minutes)
Nu
m
b
er o
f clo
n
es
No triclosan exposure
Triclosan exposure
d) E. coli mutant strain
0
5
10
15
20
25
38
0-
38
9
39
0-
39
9
40
0-
40
9
41
0-
41
9
42
0-
42
9
43
0-
43
9
44
0-
44
9
45
0-
45
9
46
0-
46
9
47
0-
47
9
48
0-
48
9
49
0-
49
9
50
0-
50
9
51
0-
51
9
52
0-
52
9
53
0-
53
9
54
0-
54
9
>5
50
Time interval (minutes)
N
u
m
b
er
o
f cl
o
n
es
No triclosan exposure
Triclosan exposure
RESPONSE TO BIOCIDE EXPOSURE
RESPONSE TO BIOCIDE EXPOSURE
-
-
POPULATION
POPULATION
Biofilm
Biofilm
-
-
number
number
-
-
biofilm phenotype
biofilm phenotype
-
-
dormancy
dormancy
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
-
-
Biofilms
Biofilms
Mycobacterium
Mycobacterium
terrae
terrae
Bacterial Resistance to Microbicides in the Healthcare Environment
Dr. Jean-Yves Maillard, University of Cardiff
Sponsored by Virox Technologies Inc. (www.virox.com)
A Webber Training Teleclass
Hosted by Paul Webber paul@webbertraining.com
www.webbertraining.com
Page 5
Establishing a concentration gradient
Establishing a concentration gradient
Diffusion
Diffusion
Interaction with cell constituents
Interaction with cell constituents
Lysed
Lysed
bacterial community
bacterial community
(mechanistic inactivation/increased organic load)
(mechanistic inactivation/increased organic load)
Enhanced bacterial insusceptibility
Enhanced bacterial insusceptibility
Degradation
Degradation
Efflux (more effective against reduced concentration)
Efflux (more effective against reduced concentration)
Early stress
Early stress
-
-
response
response
Slow growth/metabolism
Slow growth/metabolism
Established a chemical gradient (reduced nutrients / O
Established a chemical gradient (reduced nutrients / O
2
2
)
)
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
-
-
Biofilms
Biofilms
Selection for increased resistance
Selection for increased resistance
Formation of packets of surviving bacteria
Formation of packets of surviving bacteria
Dormant cells (might grow rapidly in the presence of
Dormant cells (might grow rapidly in the presence of
exudate
exudate
released from
released from
lysed
lysed
community)
community)
Acquisition of new resistant determinants
Acquisition of new resistant determinants
Increased genetic exchange
Increased genetic exchange
Intrinsic resistance
Intrinsic resistance
Type of bacteria
Type of bacteria
RESISTANCE MECHANISMS
RESISTANCE MECHANISMS
-
-
Biofilms
Biofilms
Adaptation
Adaptation
-
-
modification of targets
modification of targets
-
-
overproduction of targets
overproduction of targets
-
-
stress response
stress response
Selection
Selection
Communication
Communication
-
-
gene transfer
gene transfer
REDEFINING RESISTANCE
REDEFINING RESISTANCE
Mycobacterium
Mycobacterium
terrae
terrae
REDEFINING RESISTANCE
REDEFINING RESISTANCE
-
-
definitions
definitions
•
•
Intrinsic and acquired resistance? The best definitions?
Intrinsic and acquired resistance? The best definitions?
•
•
Biofilm resistance
Biofilm resistance
•
•
Environmental resistance
Environmental resistance
-
-
growth conditions; nutrient limitation
growth conditions; nutrient limitation
-
-
cell uptake; lower amount taken by cell grown in broth
cell uptake; lower amount taken by cell grown in broth
Brill et al. Int J Hyg Environ Health 2006; 209: 89-95
-
-
metabolic status
metabolic status
-
-
cell envelope plasticity
cell envelope plasticity
(exacerbated in biofilms)
(exacerbated in biofilms)
•
•
High
High
-
-
concentration
concentration
-
-
emerging microbial resistance unlikely but NOT impossible
emerging microbial resistance unlikely but NOT impossible
-
-
microbial contamination of undiluted formulations (e.g. QACs)
microbial contamination of undiluted formulations (e.g. QACs)
-
-
bacterial survival in glutaraldehyde (2%
bacterial survival in glutaraldehyde (2%
v/v
v/v
), chlorine dioxide
), chlorine dioxide
(2.25%
(2.25%
v/v
v/v
)
)
•
•
Low
Low
-
-
concentration
concentration
-
-
emerging microbial resistance?
emerging microbial resistance?
-
-
interaction with the microbial cell?
interaction with the microbial cell?
-
-
eliciting stress response mechanisms?
eliciting stress response mechanisms?
-
-
selection of surviving clones?
selection of surviving clones?
RESISTANCE: A GENUINE CONCERN?
RESISTANCE: A GENUINE CONCERN?
RESISTANCE: A GENUINE CONCERN?
RESISTANCE: A GENUINE CONCERN?
•
•
Evidence of microbial resistance in practice
Evidence of microbial resistance in practice
-
-
inappropriate usage
inappropriate usage
-
-
use of weak solutions &
use of weak solutions &
‘
‘
topping
topping
-
-
up
up
’
’
of containers
of containers
-
-
CHX used at a concentration of 1 in 5000 (200
CHX used at a concentration of 1 in 5000 (200
µ
µ
g
g
/ml)
/ml)
-
-
inactivation of
inactivation of
QACs
QACs
by the presence of cotton
by the presence of cotton
-
-
inactivation by organic load
inactivation by organic load
–
–
veterinary / environment
veterinary / environment
-
-
neutralization
neutralization
. hand creams containing anionic emulsifiers and cationic antise
. hand creams containing anionic emulsifiers and cationic antise
ptics
ptics
. anionic surfactant with cationic disinfectant
. anionic surfactant with cationic disinfectant
•
•
Emerging reports are rare
Emerging reports are rare
(are incidents all reported?)
(are incidents all reported?)
•
•
No information on the effect of new biocide products/surfaces
No information on the effect of new biocide products/surfaces
-
-
to early / not studied
to early / not studied
Bacterial Resistance to Microbicides in the Healthcare Environment
Dr. Jean-Yves Maillard, University of Cardiff
Sponsored by Virox Technologies Inc. (www.virox.com)
A Webber Training Teleclass
Hosted by Paul Webber paul@webbertraining.com
www.webbertraining.com
Page 6
RESISTANCE: A GENUINE CONCERN?
RESISTANCE: A GENUINE CONCERN?
•
•
Difficult to produce resistant mutants in vitro
Difficult to produce resistant mutants in vitro
-
-
well
well
-
-
documented (in vitro) studies on bacterial interaction with
documented (in vitro) studies on bacterial interaction with
low
low
-
-
biocide concentration
biocide concentration
-
-
selection
selection
-
-
induction/expression of resistant phenotype
induction/expression of resistant phenotype
-
-
stepwise training best method (unrealistic?)
stepwise training best method (unrealistic?)
RESISTANCE: A GENUINE CONCERN?
RESISTANCE: A GENUINE CONCERN?
•
•
Cross
Cross
-
-
and co
and co
-
-
resistance
resistance
-
-
evidence in vitro only
evidence in vitro only
-
-
no evidence in practice
no evidence in practice
(not documented or reported)
(not documented or reported)
-
-
no
no
in situ
in situ
evidence of microbicides selecting for antibiotic
evidence of microbicides selecting for antibiotic
resistance at present
resistance at present
(does not account for the increase usage of low concentrations o
(does not account for the increase usage of low concentrations o
f
f
microbicides)
microbicides)
-
-
surveillance programmes
surveillance programmes
(ongoing)
(ongoing)
Making predictions is difficult,
Making predictions is difficult,
Particularly about the future.
Particularly about the future.
Sam Goldwyn
The Next Few Teleclasses
April 25
Making Infection Control Really Work
… with Prof. Seto Wing Hong, University of Hong Kong
April 26
Environmental Surveillance for Infection Control
… with Andrew Streifel, University of Minnesota
May 8
Panton-Valentine Leucocidin Producing Staphylococcus aureus
… with Brenda Dale & Adam Brown, National Health Service, UK
May 10
Infection Control in the Dialysis Clinic
… with Dr. Charmaine Lok, University of Toronto
May 17
Ethics of Care During a Pandemic
… with Dr. Eric Wasylenko, Calgary Health Board
For the full teleclass schedule – www.webbertraining.com
For registration information www.webbertraining.com/howtoc8.php
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