1. Biofilms on Medical Devices
Silke S. Talsma, Ph.D.
C.R. Bard, Inc.

2. Outline The biofilm problem Antibiotic resistance
Biofilm on urinary catheters
Biofilm on endotracheal tubes

3. The Biofilm Problem

4. Biofilms are everywhere

5. Diseases caused by biofilm
Device related infections
Cystic fibrosis
Plaque; Gingivitis
Ear infection
Bacterial endocarditis
Chronic prostatitis
The Centers for Disease Control and the National Institutes of Health estimate that 65% to 80% of all chronic infections can be attributed to microbial biofilms.

6. What is a biofilm?
A collection of microorganisms on a surface that is surrounded by an extracellular matrix made up of primarily polysaccharide materials

7. Stages of Biofilm Formation
Bacteria switch from a free-floating (planktonic) state where they function as individuals to a sessile state where they function as communities

8. Biofilms move along the extraluminal or intraluminal surface of medical devices

9. A closer look at biofilms Extracellular Matrix
Microorganisms in biofilms are surrounded by a protective extracellular
matrix
Microorganisms in a biofilm can be 1,000 fold less susceptible to
antibiotics than planktonic microorganisms

10. Bacteria are protected in a biofilm

11. Antibiotic Resistance

12. Antibiotic Resistance in Biofilms
Tolerance in biofilms makes antibiotics less
effective
Up to 1,000 fold less susceptible to antibiotics
Selection for bacteria that are more resistant
to antibiotic
Spread of antibiotic resistance
Antibiotics kill bacteria except the resistant ones, which multiply, and in the end there are more resistant than non-resistant bacteria

13. Multiresistant Bacteria
2 million healthcare-associated infections occur every year; 70% of the pathogens causing them are resistant to at least one antibiotic
Numbers of healthcare-associated as well as community associated MRSA are increasing
Horizontal gene transfer is promoted in biofilms; therefore, it is possible that antibiotic resistance spreads more easily than in planktonic populations
Antibiotic resistant bacteria are common in VAP

14. Antimicrobials
Antibiotics => very specific, highly efficient, prone to development of resistance
Antiseptics, antimicrobials (for example silver) => broad spectrum

15. Biofilms on Foley catheters

16. Biofilms on Foley catheters
Intraluminal contamination from the
Collection bag
Extraluminal contamination
at the insertion site

17. Biofilms and infection
The catheter is COLONIZED, the patient is INFECTED
Bacteria can survive/multiply in biofilm. Biofilm provides reservoir for bacteria
Microorganisms are detached from the biofilm and can infect a patient
The presence of a biofilm strongly increases the likelihood that bacteria are available for infection

18. Immune response to a biofilm
The bladder, ureter and urethra are lined with epithelial cells

19. Immune response to a biofilm
Microorganisms colonize epithelium
Microorganisms manage to get into tissue (either by damaging the tissue with toxin or by specific virulence mechanism)
Microorganisms multiply in tissue, spread into lymphatic organs, and eventually in blood
Immune system mobilizes cells to eliminate bacteria = Inflammation

20. Incidence of CA-UTI Bacteriuria occurs in about 26% of patients
Symptomatic UTI: 16-32% of those who are bacteriuric
Bacteremia related to CAUTI: 3.6% of those with bacteriuria, attributable mortality 12.7%
(Saint, AJIC 2000;28:68-75.)

21. Microbiology of CA-UTI

22. Biofilms on Foley catheters
Prevention:
trained personnel, aseptic technique
handwashing
Closed system
proper securement
Assess if Foley catheter is still necessary
CDC recommendations:

23. Biofilms on endotracheal tubes

24. Biofilm on endotracheal tubes
In addition to microorganisms and microbial secretions there are also other components, such as mucus, blood cells, pollen particles etc...

25. Biofilms on endotracheal tubes
Mucus is part of the host immune system, it traps particles such as bacteria, also prevents tissues from drying out.
In the healthy body, mucus is swept away by cilia, and for the most part swallowed and digested.
Removal of mucus by natural mechanisms does not occur in the intubated patient and it can accumulate above the cuff, or inside the ET tube
Cough reflex does not work effectively in intubated patient, so if mucus particles with bacteria reach the lower respiratory tract, they can grow and spread and lead to infection

26. Biofilms on endotracheal tubes
Pooled secretions
above the cuff
Oral Biofilm
Intraluminal contamination from
the ventilator or suction catheter

27. Oral biofilm
In a healthy adult, the oral cavity is colonized by more than 500 different
kinds of bacteria (most of them are normal flora and do not cause harm).
In the intubated patient, natural defense mechanisms, such as saliva production
and swallowing are impaired
Oral hygiene of intubated patients is difficult, because access is limited and
it requires a substantial amount of nursing time
If microorganisms are not sufficiently removed from the tooth surface, they
colonize and form a biofilm (Plaque)
If the plaque is not removed, the secretions in the biofilm (acids and sugars) can
cause inflammation and damage to the teeth and gums (gingivitis)

28. Biofilms on endotracheal tubes
ICU patients were swabbed to determine the colonization of the upper and lower
Respiratory and GI regions
Mouth/Oropharynx
Upper GI tract
Lower Respiratory Tract
Inner lumen of ETT
Gram negative bacteria
Gram positive bacteria
Feldman et al., 1999

29. Biofilms on endotracheal tubes
Etiology shifts over intubation period: initially endogenous flora, later on exogenous, harder to treat microorganisms
intubation
> 80% of intubated
patients are extubated
by day 10
< 5 days
≥ 5 days
Streptococcus pneumoniae
Haemophilus influenzae
AB sensitive Staphylococcus aureus
MRSA
Enterobacteriaceae (e.g. Klebsiella, E. coli)
AGBN (Pseudomonas, Acinetobacter)
Early onset
Late onset

30. When Biofilms spread into the lower respiratory tract, they can cause VAP
Microaspiration at the cuff
Accumulation in the carina
Aerosolization from the inside
of the tube into the lung

31. Biofilms on endotracheal tubes
Prevention - The IHI Ventilator Bundle
Elevated bed position => avoids contamination by gastric reflux
Daily sedation vacations and assessment of readiness to extubate
peptic ulcer disease prophylaxis
deep venous thrombosis prophylaxis
Silver-coated endotracheal tube reduced the incidence of VAP in a
Multicenter clinicial trial (Kollef et al. 2008: JAMA 300(7): )
VAP bundle:

32. Summary
Microorganisms form biofilms on surfaces such as medical devices
Biofilms provide protection for microorganisms and make them more resistant to antibiotic treatment
National organizations recommend bundle strategies to prevent device related infections