Biofilms on Medical Devices

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Biofilms on Medical Devices

• Silke S. Talsma, Ph.D.
• C.R. Bard, Inc.

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Outline

• The biofilm problem
• Antibiotic resistance
• Biofilm on urinary catheters
• Biofilm on endotracheal tubes

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The Biofilm Problem
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Biofilms are everywhere
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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.
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What is a biofilm?

• A collection of microorganisms on a surface that
  is surrounded by an extracellular matrix made up
  of primarily polysaccharide materials

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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

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Biofilms move along the extraluminal or
intraluminal surface of medical devices
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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

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Bacteria are protected in a biofilm
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Antibiotic Resistance
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Antibiotic Resistance in Biofilms
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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

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Antimicrobials

• Antibiotics gt very specific, highly efficient,
  prone to development of resistance
• Antiseptics, antimicrobials (for example silver)
  gt broad spectrum

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Biofilms on Foley catheters
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Biofilms on Foley catheters
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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

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

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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 20002868-75.)
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Microbiology of CA-UTI
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Biofilms on Foley catheters

• Prevention
• trained personnel, aseptic technique
• handwashing
• Closed system
• proper securement
• Assess if Foley catheter is still necessary
• CDC recommendations http//www.cdc.gov/ncidod/dhq
  p/gl_catheter_assoc.html

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Biofilms on endotracheal tubes
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Biofilm on endotracheal tubes

• In addition to microorganisms and microbial
  secretions there are also other components, such
  as mucus, blood cells, pollen particles etc...

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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

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Biofilms on endotracheal tubes
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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)

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Biofilms on endotracheal tubes
ICU patients were swabbed to determine the
colonization of the upper and lower Respiratory
and GI regions
Feldman et al., 1999
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Biofilms on endotracheal tubes

• Etiology shifts over intubation period initially
  endogenous flora, later on exogenous, harder to
  treat microorganisms

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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

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Biofilms on endotracheal tubes

• Prevention - The IHI Ventilator Bundle
• Elevated bed position gt 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)805-13.)

VAP bundle http//www.ihi.org/IHI/Topics/Critical
Care/IntensiveCare/Changes/ImplementtheVentilatorB
undle.htm
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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