1. health and fitness
2. disease

Hospital biofilms;
the challenge for endoscope
decontamination
Thomas Vanzieleghem – R&D Manager
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Where can biofilms be found?
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What is a biofilm?
Definition
Biofilms are complex, surface-dwelling communities of microorganisms encased
in a self-produced matrix of polymers
EPS Matrix*
Multiple roles:
- Mechanical cohesion within the biofilm
- Protective envelope
- Water retention
EPS binding
bacteria
together
* EPS = Extracellular Polymeric Substances
HELPING
Source : Flemming & Windenger, Nature Reviews Microbiology,
2010 HEALTHCARE TO BE BIOFILM FREE
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4 steps of biofilm development
1.
2.
3.
4.
Adhesion to a surface
Accumulation (growth)
Maturation
Dispersal
Source : Otto, Nature Reviews Microbiology, 2009
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Growth Time
4 key factors : Microbial species, Nutriments, Temperature and Humidity
Source : Otto, Nature Reviews Microbiology, 2009
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What happens inside biofilms?
Biofilms favour horizontal gene transfer between bacteria (notably of antibiotic
resistance)
Recent examples of antibiotic resistance gene
transfer in biofilms:
• Tetracyclin, gentamycin and chloramphenicol in
E. coli (Krol et al., 2013)
• Beta-lactamase (CTX-M-15) between
enterobacteriaceae (Hennequin et al., 2012)
• Gentamycin and chloramphenicol in
Staphylococcus aureus (Savage et al., 2013)
Source : Madsen et al., 2012
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Biofilm = High resistance
The cause of this resistance?
• Some micro-organisms are in metabolic latency; they are called persisters.
• Diffusion of anti-microbial compounds in biofilms is limited
Biofilms can re-develop
after disinfection!
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Historical link between biofilm and diseases
The work of Bill Costerton – A pioneer in biofilm research
Established the link between biofilms and diseases
Source : Lappin-Scott, Nature Reviews Microbiology, 2014
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Biofilms on the front page
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Biofilms and infections
The ECDC estimates that 4.1 million patients contract a nosocomial infection
every year in Europe
Biofilms are responsible for 65 % of infections on average*
• Biofilms = direct cause of infections
Core of the problem. Biofilms grow in or on the patient’s body
• Biofilms = indirect cause of infections
Source of the contamination, reservoir of pathogens with
which patients come into contact
* Costerton J. W., Cystic fibrosis pathogenesis and the role of biofilms in persistent infection.
Trends in Microbiology 9 (2), 2001
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Biofilm = indirect cause of infections
Biofilms are also reservoirs of pathogenic germs within the hopital
Susceptible host
(patient)
Air
Vectors
Direct contact
Reservoirs
Causal agent
(pathogens)
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Reservoirs and biofilms
Reservoirs of pathogens are niches that shelter germs and protect them until
they are released into the environment
In hospitals
Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacter baumanii,
Clostridium difficile have been found in biofilm on :
•
•
•
•
•
Sinks
Furniture
Clinical surfaces in ICU
Reusable objects (after cleaning)
Medical Devices
(Hota, 2004; Vickery et al., 2012; Yezli et al., 2012)
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Reservoir = Vector?
In some cases, a reservoir can also be a vector and contaminate patients by
direct contact
Example:
• Endoscopes
These medical devices are thoroughly cleaned and disinfected but biofilms may
resist and persist on their surfaces.
“more healthcare–associated
outbreaks have been linked to
contaminated endoscopes than to any
other medical device.” CDC
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The battle against biofilms : challenges
Objective : to reduce the risk of transmission of pathogenic germs causing
nosocomial infections associated with biofilms
Detection
Prevention
Treatment/
Cleaning
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The battle against biofilms : challenges
Prevention of biofilms
Design of medical devices should incorporate a choice of materials and cleaning
procedures that limit/inhibit biofilm development
Examples :
• Materials that compose endoscopes
• Design of endoscopes
• Detergents that remove biofilms at early stages
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The battle against biofilms : challenges
Detection of biofilms
In the laboratory, several means exist to highlight the presence of biofilm:
• Microscopy (optical and electronic)
• Spectroscopy (FTIR)
• …
Source : Brazilian journal of infectious diseases
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The battle against biofilms : challenges
Detection of biofilms
In the field, biofilm on endoscopes may remain undetected by classical
techniques :
• Little or no sampling of germs in a biofilm
• Underestimation of viable non culturable (VNC) bacteria
• Direct visualization is difficult or even impossible
Need for new detection standards
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The battle against biofilm: challenges
Treatment / cleaning of biofilm on inert surfaces
Where classical chemistry can have limitations, specialized enzymatic chemistry
brings solutions to degrade the biofilm EPS matrix
Specific enzymes that degrade EPS
Disinfectants
Freed persisters, more sensitive
Weakened integrity of the biofilm
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Case study – Belgian hospital
Context :
A Belgian hospital experienced an outbreak of Carbapenemase Resistant
Enterobacteriaceae (CRE). Endoscopes were suspected to be a reservoir.
Objective :
Diagnosis of microbiological contamination in flexible endoscopes (particularly
related to biofilm)
Material analysed :
8 gastroscopes and 1 fibroscope
Current protocol :
Manual pre-cleaning before complete cycle in EWD
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Case study – Belgian hospital
Sampling and analysis methods
• Sampling with 120 ml of Thio T+ Solution* flushed through endoscope channels
• ATP 2G analysis - culture independent estimation of microbial count
1.
2.
3.
Bacteria are filtered out from the sample (0.22 μm)
Lysis and recovery of ATP
Negative
Quantification of ATP
Positive
• SLYM-BART® test
SLYM-BART® is a growth-based test enabling the
detection of biofilm forming bacteria in a sample
* Tween 80, Lecithin, Thiosulfate and Histidine
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Case study – Belgian hospital
Results
Bart-Test :
ATP 2G :
cATP (pg/ml)
<1
1-10
>10
Turbidity appears
6-7 days
4-5 days
1-3 days
Contamination
Negative
Alert
Positive
Contamination
Negative
Alert
Positive
BART test
ATP 2G
Results (# endoscopes)
+
+
4
+
-
3
Alert
+
1
Alert
-
1
-
+
0
-
-
0
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Case study – Belgian hospital
Metagenomic analysis (1 endoscope)
Comparative analysis of sampling before and after a treatment with OneLIFE
Enzyscope MD revealed large diversity
Large increase in proportion !
Before
After
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Case study – French hospital
2 pairs of endoscopes
Thorough cleaning
(OneLIFE protocol)
Group 1 – Routine protocol*
Group 2 – OneLIFE protocol*
Thorough cleaning
Thorough cleaning
(OneLIFE protocol)
(OneLIFE protocol)
* Manual cleaning
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Case study – French hospital
Timeline
BART
ATP 2G
+
+
+
-
Alert
+
Alert
-
-
+
-
-
23/09/2014
05/11/2014
08/01/2015
17/02/2015
GP1 – A
GP2 – A
GP1 – A
GP1 – B
GP1 – B
GP2 – A
GP2 – B
GP1 – A
GP1 – A
GP2 – A
GP2 – B
GP1 – B
GP2 - B
GP2 – A
GP2 – B
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Conclusions
Biofilms …
• are fundamentally different from planktonic germs
• cases of infections due to contaminated endoscopes, sometimes linked to
biofilm
• biofilm contamination may not be detected by conventional sampling methods
and analyses
• may resist classical cleaning and disinfection procedures
A specific approach is required to tackle the biofilm issue
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Thank you for your attention, any questions?
OneLIFE SA
Parc Scientifique Einstein
15 avenue Albert Einstein
1348 Louvain-la-Neuve
Belgium
Tel : +32 (0)10 48 34 27
Fax: +32 (0)10 45 63 63
www.onelife-biofilmfree.com
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