Microbiology 2 Infection Control DN8

1
Microbiology 2Infection ControlDN8

• Dr Viv Rolfe

Alternative formats and large print versions of
these handouts are available upon request.
2
Lecture Summary

• Global and UK problem of infections
• Causes of infections
• Commensal and pathogenic infection
• 5 steps to an infection
• Microbe-host interaction the bodys response to
  infection
• Topical issues
• Hospital-acquired infection
• Super-bugs

3
What is an Infection?

• Infection - microbes enter the host, multiply and
  cause tissue damage.
• It is a communicable disease i.e. can be passed
  between people.

4
Global Problem

• 41 of global disease is infectious.
• HIV / AIDS, tuberculosis and malaria cause
  millions of deaths each year.

WHO World Health Organisation
5
UK Problem

• 40 of people will visit health care
  professionals because of infections each year.
• Food poisoning the most common.
• 5,000 patients die from hospital acquired
  infections each year.
• Many national crises have been due to infection,
  e.g. BSE and CJD, meningitis, E. coli O157
  outbreaks

6
Cases of Infection in the UK each Year
82,000 cases of food poisoning...
SourceCommunicable disease surveillance centre
7
(No Transcript)
8
What other infections have been in the news?
?
9
What Causes Infection?
10
What Causes Infection?

• Micro organisms
• Bacteria
• Viruses
• Fungi
• Protozoa
• Prions (small infectious proteins which dont
  have a genome)
• Parasites

11
Name the Type of Microbe!
12
MOULD
13
BACTERIA
ROD/ BACILLUS
COCCI
SPIRAL
14
VIRUSES
15
PROTOZOA
e.g. flagellate
e.g. amoeba
16
PRIONS
3.9
17
PARASITE
Tape worm
18
It could be a commensal in the wrong place at the
wrong time

• Commensal a organism which lives in association
  with another and is harmless.
• Colonisation - the growth of organisms at a
  site.
• Flora - micro-organisms resident in a body site
  e.g. skin, gut.

19
Guess which are commensal colony sitesin the
body.
20
Harbours commensal flora
Is sterile
21
Harbours commensal flora
Is sterile
22
Harbours commensal flora
Is sterile
23
Harbours commensal flora
Is sterile
24
Harbours commensal flora
Is sterile
25
Harbours commensal flora
Is sterile
26
Harbours commensal flora
Is sterile
27
Harbours commensal flora
Is sterile
28
Harbours commensal flora
Is sterile
29
Harbours commensal flora
Is sterile
30
Harbours commensal flora
Is sterile
31
Harbours commensal flora
Is sterile
32
Infections can be caused by pathogens (not
commensal to the body)
Pathogen Name Disease
Fungus Tinea Pedis Atheletes foot Jock itch (groin)
Virus Hepatitis B Hepatitis B
Human Immuno-deficiency Virus (HIV) HIV leading to aids
Bacteria Mycobacterium tuberculosis Tuberculosis TB
Clostridium difficile (C diff) Diarrhoea
Protozoa Entamoeba histolytica Amoebic Dysentry
Parasites Tapeworm Malnutrition
33
Infections
34
5 Steps to Infection

• The presence of an inFectious Agent
• A Reservoir where agent is multiplying and
  waiting to infect!
• A route of Transmission.
• A route of Entry into host.
• Inadequate natural defenses in a Susceptible
  individual

35
Name some possible reservoires in a hospital ward.
?
36
Reservoires
37
Name some possible routes of transmission in a
hospital ward.
?
38
e.g. air, water, touch or a vector (mosquito)
39
How does the Body Respond to Infection?
40
Fatal if growthof microbescontinues
Number ofpathogens
Acute illness
Microbes respondingto therapy and immunity
Prodromal
Incubation
41
Depends on Susceptibility

• Healthy individuals combat infection so only
  suffer acute (short term) illness.
• In susceptible groups infection can be worse.
• Older/younger
• Pregnancy
• Poor nutrition
• Illness
• Medication, drugs and surgery
• Stress
• Genetic predisposition

42
Body response to infection

• Local inflammation (reaction by innate and
  acquired immune defenses).
• Systemic response including release of pyrogens
  in the blood which cause fever.

43
Localised swelling/odema
44
The immune system provides a defence against
infection.Sometimes, a pathogen combats our
defences.
HIV Virus
Virus particles
Attackinglymphocytes inthe immune system
45
Topical Issues
46
HAIHospital or Healthcare Acquired Infections
47
Statistics

• 1 in 10 people will acquire a hospital
  infection.
• They cost the health sector 1 billion pounds per
  year.
• People spend 2.5 times longer in hospital.
• Also known as NOSOCOMIAL infections.

48
Causes of HAI

• Susceptible hosts stressed, ill health,
  medication.
• Close proximity to other people.
• Drugs dont work.
• Inadequate infection control (e.g. washing
  hands).

49
MOST COMMON INFECTIONS Blood infection via
needles, drips Infection after surgery Skin Chest
Urinary tract
50
C dif
E coli
MOST COMMON BUGS E coli Staphylococcus Candida Clo
stridium difficile
Staphy
Candida
51
The Matrons Charter (2004)

• 10 principals for delivering cleaner hospitals
• Matrons to organise cleaning
• Patient feedback
• Infection control training

52
Drug Resistant Micro-organisms
53
Drug Resistant Micro-organisms

• These SUPER-BUGS make HAI an evengreater
  problem.
• Increasing numbers of bacteria are resistant to
  antibiotics so many HAI cannot be treated.
• MRSA kills 5000 people each year.

54
Superbugs.
Methicillin-resistant Staphylococcus aureus
MRSA Oxicillan-resistant S. aureus
ORSA Vancomycin-resistant Enterococci VRE
55
MRSA / ORSA
Staphy

• Staphy is a commensal living on the skin
• It can infect the lungs causing pneumonia
• Transmitted by physical contact and in the air
• Current preventive measures - hand washing and
  patient isolation

56
VRE

• Commensal Enterococci in the gut
• Infects vulnerable and long stay patients
• Causes urinary tract infection e.g. associated
  with use of catheters.

57
Lecture Summary

• Global and UK problem of infections
• Causes of infections
• Commensal and pathogenic infection
• 5 steps to an infection
• Microbe-host interaction the bodys response to
  infection
• Topical issues
• Hospital-acquired infection
• Super-bugs