microbiology 2 infection control dn8
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Microbiology 2 Infection Control DN8. Dr Viv Rolfe. Alternative formats and large print versions of these handouts are available upon request. Lecture Summary. Global and UK problem of infections Causes of infections Commensal and pathogenic infection 5 steps to an infection - PowerPoint PPT PresentationTRANSCRIPT
Microbiology 2Microbiology 2Infection ControlInfection Control
DN8DN8
Dr Viv Rolfe
Alternative formats and large print versions
of these handouts are available upon request.
Lecture SummaryLecture Summary
• Global and UK problem of infections
• Causes of infections– Commensal and pathogenic infection– 5 steps to an infection– Microbe-host interaction – the body’s response
to infection
• Topical issues– Hospital-acquired infection– Super-bugs
What is an Infection?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.
•41% of global disease is infectious.
HIV / AIDS, tuberculosis and malaria cause millions of deaths each year.
Global ProblemGlobal Problem
WHO – World Health Organisation
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
UK ProblemUK Problem
6379
3293
22652251
2111
1879
1587
1444
1110 658Tuberculosis
Viral hepatitis
Measles
Meningitis
Mumps
Scarlet Fever
Rubella
Dysentery
Malaria
Whooping cough
+82,000 cases of food poisoning...
Source:Communicable disease surveillance centre
Cases of Infection in the UK each Year
What other infections have
been in the news?
What Causes What Causes Infection?Infection?
What Causes Infection?What Causes Infection?
• Micro organisms…– Bacteria– Viruses– Fungi– Protozoa
• Prions (small infectious proteins which don’t have a genome)
• Parasites
Name the Type of Name the Type of Microbe!Microbe!
MOULD
BACTERIA
COCCI
ROD/
BACILLUS
SPIRAL
VIRUSES
PROTOZOA
e.g. amoeba
e.g. flagellate
3.9
PRIONS
PARASITE
Microscopic tic Worm – visibleto the eye
Tape worm
It could be a commensal in the It could be a commensal in the wrong place at the wrong timewrong 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.
Guess which are commensal colony sitesin the body.
Is sterile
Harbours commensal flora
BloodVagina
Eyelids
CerebroSpinalfluid
External
ear canalColon
Skin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
Vagina
Eyelids
CerebroSpinalfluid
External
ear canalColon
Skin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
Vagina
Eyelids
CerebroSpinalfluid
External
ear canalColon
Skin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
Vagina
Eyelids
CerebroSpinalfluid
External
ear canalColon
Skin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
Vagina
Eyelids
CerebroSpinalfluid
External
ear canalColon
Skin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
Vagina
Eyelids
CerebroSpinalfluid
External
ear canalColon
Skin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
Vagina
Eyelids
CerebroSpinalfluid
External
ear canalColon
Skin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
Vagina
Eyelids
CerebroSpinalfluid
External
ear canal
ColonSkin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
Vagina
Eyelids
CerebroSpinalfluid
External
ear canal
ColonSkin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
Vagina
Eyelids
CerebroSpinalfluid
External
ear canal
ColonSkin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
Vagina
Eyelids
CerebroSpinalfluid
External
ear canal
ColonSkin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Is sterile
Harbours commensal flora
Blood
VaginaEyelids
CerebroSpinalfluid
External
ear canal
ColonSkin
Upper
Respiratory
tract
Internal
organs
Urethraopening
Semen(prior tourethra)
Infections can be caused by Infections can be caused by pathogens (not commensal to pathogens (not commensal to the body)the body)
Pathogen Name Disease
Fungus Tinea Pedis Athelete’s footJock 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
InfectionsInfections
5 Steps to Infection5 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
Name some possible
reservoires in a hospital ward.
Reservoires
Name some possible routes of transmission in a
hospital ward.
e.g. air, water, touch or a vector (mosquito)
How does the Body How does the Body Respond to Infection?Respond to Infection?
Number ofpathogens
Incubation
Nosymptoms
Prodromal
Mildsymptoms
Acute illness
Identifiablesymptoms
Fatal if growthof microbescontinues
Recovery
Microbes respondingto therapy and immunity
Depends on SusceptibilityDepends 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
Body response to infectionBody response to infection
• Local inflammation (reaction by innate and acquired immune defenses).
• Systemic response including release of pyrogens in the blood which cause fever.
Localised swelling/odemaLocalised swelling/odema
Virus
particles
Attackinglymphocytes in
the immune system
The immune system provides a defence against infection.Sometimes, a pathogen combats our defences.
HIV Virus
Topical IssuesTopical Issues
HAIHospital or Healthcare Acquired Infections
StatisticsStatistics
• 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.
Causes of HAICauses of HAI
• Susceptible hosts – stressed, ill health, medication.
• Close proximity to other people.
• Drugs don’t work.
• Inadequate infection control (e.g. washing hands).
MOST COMMON INFECTIONS
Blood infection via needles, drips
Infection after surgery
Skin
Chest
Urinary tract
MOST COMMON BUGS
E coli
Staphylococcus
Candida
Clostridium difficile
E coliC dif
Staphy Candida
The Matron’s Charter (2004)
• 10 principals for delivering cleaner hospitals
• Matrons to organise cleaning
• Patient feedback• Infection control training
Drug Resistant Micro-organismsDrug Resistant Micro-organisms
Drug Resistant Micro-organismsDrug 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.
Methicillin-resistant Staphylococcus aureus MRSA
Oxicillan-resistant S. aureus ORSA
Vancomycin-resistant Enterococci VRE
Superbugs….Superbugs….
•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
MRSA / ORSAMRSA / ORSA Staphy
•Commensal Enterococci in the gut
•Infects vulnerable and long stay patients
•Causes urinary tract infection e.g. associated with use of catheters.
VREVRE
Lecture SummaryLecture Summary
• Global and UK problem of infections
• Causes of infections– Commensal and pathogenic infection– 5 steps to an infection– Microbe-host interaction – the body’s response
to infection
• Topical issues– Hospital-acquired infection– Super-bugs