Cardiovascular Infections

1
Cardiovascular Infections
2
Normal flora and defenses

• Sterile site
• Has NO normal flora.
• Inaccessible ? (no relatively easy and regular)
• Unsuitable? (you have got to be kidding!)
• PROTECTED? (Yes!)
• Defenses
• Mechanical (moving and teflon like endothelium)
• Biological
• Circulating immune cells and molecules
• Reticulo-endothelial system

3
Bacteria in bloodstream

• Bacteraemia
• Transient presence.
• Organisms not multiplying.
• Patient asympotomatic.
• Important means of spread for other diseases.
• Septicaemia
• Organisms actively multiplying.
• Acutely symptomatic

4
Bacteraemia or Septicaemia
Bacteria enter the bloodstream
bacteraemia
septicaemia

• MICROBE
• virulence
• number

HOST - susceptibility

• Examples
• Oral organisms and cardiac defects
  endocarditis.
• Meningococci and meningitis
• Bowel organism and perforation. (Strongyloides
  bedtime story)

5
Septicaemia

• Symptoms
• Fevers, chills, spiking temperature, rigors
• Rash (petaechial)
• Mortality
• Very high even with prompt therapy.
• Gram positive 10 20
• Gram negatuve 25 40
• Septic shock 40 90

6
Septic shock

• Gram positive some exotoxins.
• Gram negative all have endotoxin.

7
You dont catch septicaemia

• Urinary tract infections
• Pyelonephritis, catheterisation.
• Respiratory tract
• Pneumonia (pneumococci)
• Colonization (meningococci)
• Abscess
• Intermittent seeding.
• Surgical (and other) wounds
• Site is an important modifier
• INDWELLING MEDICAL DEVICES

8
Venous catheter related BSIs

• Commonest cause of BSIs in Australia.
• 3500 cases annually (1.5 CR-BSI per 1000
  admissions)
• 25 case fatality (50 of which is directly
  attributable)
• Location of venous line
• Central line has 20X daily risk of peripheral
  line
• Access
• Down outside of catheter, in catheter, in
  infusate
• Prevention / treatment
• Minimize use and duration, optimize location.
• Teams for insertion and care
• Antibiotics and REMOVAL
• Antibiotic impregnated devices

Collignon Aus Prescriber Vol 26, No 2, 2003.
9
Blood cultures
Urine
Blood
days
Blood
Broth
10
Blood cultures

• Need a specimen collection and culture strategy
  to deal with small numbers of organisms that may
  be present intermittently.
• Multiple collections (3 in 24 hours)
• Maximum volume (do not overfill!)
• Aseptic collection / handling technique is
  CRITICAL
• What if patient has venous catheter?
• Do not take from catheter line!

11
Bacterial endocarditis

• Infection of endocardium
• Portal of entry - primary focus / event
• - minor breach

12
Bacterial endocarditis

• ACUTE versus SUB ACUTE
• Progression, virulence of organism, host factors
• Diagnosis
• Clinical (sounds), blood culture
• Treatment
• Prolonged aggressive combination therapy.
• Prevention
• Prophylactic antibiotics for those AT RISK
• Previous endocardial damage or susceptibility
• PLUS procedures producing bacteraemia