INFECTION CONTROL
CHAINS OF INFECTION
There are a variety of steps in the process of infection
moving from one person I host to another It requires
An infectious
agent i
Reservoir s
Portal of exit 2
Means of transmission 4
Portal of entry 3
A susceptible host
Epidemicpotential An organism has the potential
to spread
readily Either person to person or
environ ental
reservoir to person
RESEVO I R S OF INFECTION
The physical environment Builtenvironment
infrastructure
Fo miles objects colonised
bymicroorganisms
Natural environments
Animals zoonoses
Food t water
PEOPLE
, PO R TA L OF E X I T F ROM RES E VO I R
We must consider how organisms move from their
reservoir to infect people As we necessarily interact
with our environments there is a risk
Legionella Complexity of hospitalbuildings
means there is a risk from water
systems most notably
Legionella pneumophila A poorly gram stained rod
shape Legion alla lives in water and causes severe
pneumonia Related to water supplies t Air conditioning
Borelli a burgdorferi Cause of Lyme disease
Spiral bacteria Cspirochaeted like Treponemapallidum
Considered a zoonosis mainly from deer Moves via the
ixodes tick an arachnidarthropod
Listeria Listeria monocytogenes Cram positive
Rod shaped can live and replicate at fridgetemps
Assumed to bepresent in unpasteuriseddairy and will
replicate if processing is not at a low temp The infection
l isteriosis is
particularlyimportant for neonates and
the elderly when it causes meningitis and in the
immunoco promised
Pregnant women should avoid soft cheese
CHAINS OF INFECTION
There are a variety of steps in the process of infection
moving from one person I host to another It requires
An infectious
agent i
Reservoir s
Portal of exit 2
Means of transmission 4
Portal of entry 3
A susceptible host
Epidemicpotential An organism has the potential
to spread
readily Either person to person or
environ ental
reservoir to person
RESEVO I R S OF INFECTION
The physical environment Builtenvironment
infrastructure
Fo miles objects colonised
bymicroorganisms
Natural environments
Animals zoonoses
Food t water
PEOPLE
, PO R TA L OF E X I T F ROM RES E VO I R
We must consider how organisms move from their
reservoir to infect people As we necessarily interact
with our environments there is a risk
Legionella Complexity of hospitalbuildings
means there is a risk from water
systems most notably
Legionella pneumophila A poorly gram stained rod
shape Legion alla lives in water and causes severe
pneumonia Related to water supplies t Air conditioning
Borelli a burgdorferi Cause of Lyme disease
Spiral bacteria Cspirochaeted like Treponemapallidum
Considered a zoonosis mainly from deer Moves via the
ixodes tick an arachnidarthropod
Listeria Listeria monocytogenes Cram positive
Rod shaped can live and replicate at fridgetemps
Assumed to bepresent in unpasteuriseddairy and will
replicate if processing is not at a low temp The infection
l isteriosis is
particularlyimportant for neonates and
the elderly when it causes meningitis and in the
immunoco promised
Pregnant women should avoid soft cheese
