Lecture 23 - Health Care Associated Infection Flashcards by Eleanor Nicklason

What are some common places where these infections can be gotten?

Nursing home
Hospital
Child care centre

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What is another word for HCAI?

Nosocomial

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What is a nosocomial infection?

Infection from a health care associated setting

May have delayed onset

We don’t count infections that are already present when first entering the setting

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How many deaths are there each year due to HCAI?

7000 in Australia annually

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How much do HCAI cost Australia each year?

180 millions

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How many people at any one time in a health care setting have an infection?

3-25%

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How can infection rates be stemmed?

Implementation of infection control programmes

1/3rd

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What are infections that result from a medical intervention?

Give some examples

Iatrogenic
• The bacteria get a ‘free ride’ into the body, past protective defences

For example:
• urine catheterisation
• hands of medical personnel
• intubation
• ventilation
• IVs (indwelling vascular lines)

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What do invasive procedures sometimes cause?

Iatrogenic infections

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How are iatrogenic infections treated?

Antibiotics

Can also be used for prophylaxis

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What can antibiotic use in the hospital lead to?

Resistance

* Antimicrobial associated diarrhoea

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What are organisational associated factors?

Name some examples

To do with the way that the hospital is organised
For example:
• air conditioning
• contaminated water systems
• staffing issues
• physical layout of facility

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Which organisms are commonly in the water system?

Are these a problem?

Pseudomonas aeruginosa
Serratia

For healthy people, it doesn’t cause disease
People with burns are, however at risk

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Which organisms are present in contaminated in the air?

• Aspergillus mould

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Which organisms are present in contaminated food?

Salmonella

* Campylobacter

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Describe the links in the chain of infection

Pathogen
Source
Transmission
Entry
Host

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What are patient associated factors?

Severity of illness
Underlying immunocompromisation
Length of stay

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What are some common sources of infection?

People:
• other patients
• staff
• visitors
• own normal flora
Environmental

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Describe how other patients often spread disease

• acute disease

person still in incubation period
chronic carriers excreting
person’s own endogenous flora
fomites contaminated with others’ bacteria

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Why is anaesthesia a predisposing factor for infection?

How can this be prevented?

Because the cilia are immobile

It is important to get the patient moving and coughing to get the cilia working again

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What factors predispose someone to infection?

Trauma (arm out window –> bacteria from road)
underlying immunosupression (age, disease)
co-morbidity (smoking, influenza)
procedures (anaesthesia)

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What are someways that the pathogen is transmitted?

Direct: person to person

Indirect: surgical instruments, fomites

Airborne: droplets

Vehicle: food, water, drugs, blood transfusion

Vector: mosquitoes, flies, rats

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What are patients colonised with soon after admittance to hospital?

Describe the common locations and pathogens

Hospital strains of bacteria
These tend to be more resistant

Colonisation of:
• skin
• GIT; VRE
• respiratory tract; Klebsiella

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Which hospital strains colonise the GIT?

VRE

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Which hospital strains colonise the respiratory tract?

Klebsiella

Which outbreaks are commonly seen in children's wards? When? How is it spread?

1\ Rotavirus outbreaks In winter Person to person 2\ Varicella Zoster Spread by aerosols

What other pathogens often cause outbreaks in hospital?

1\ Norovirus Aerosols, surfaces 2\Influenza Aerosol spread

Which infections are most common? | Which are serious?

* UTI 30-45% * Surgical wound 15-30% * LRT 10-25% * Skin 5-10% * Blood 5-10% Serious: septicaemia, burn infection, LRT infection Not so serious: UTI Surgical wound

Which bacteria commonly cause infection in hospitals?

* Staph. aureus * Staph. epidermidis * Pseudomonas aeruginosa * Enterobacteria (Klebsiella, E. coli) * Acinetobacter • Clostridium difficile

Which yeast is commonly seen in hospital infection? Why is it often seen in hospitals?

• Candida albicans | Overgrowth due to antibiotics use The antibiotics clear the bacteria, giving the yeast a chance to grow

Describe the main features of C. difficile

Spore forming Gram positive rod Anaerobic

Which mould is commonly seen in hospital infections?

• Aspergillus

How is C. difficile transmitted?

* Shed from infected people * Spores survive on surfaces * Hands of health care workers transmit the spores to patients

How can we kill spores and remove them from surfaces? | How about from hands?

• Bleach (Resistant to normal methods) • soap and water (alcohol gel not enough)

What predisposes someone to C. difficile infection?

* Broad spectrum Antibiotics --> disruption of normal flora * prolonged hospital stay * antacid use * sharing room with infected person * NG tube

What does infection of C. difficile result in?

Ranges from: • Mild diarrhoea • Pseudo-membranous colitis (sometimes fatal)

What are the symptoms of C. difficile infection?

* Cramping abdominal pain | * Watery diarrhoea (can be bloody)

How do we treat C. difficile infection?

• Removal of antibiotics | Metronidazole

What is the hypervirulent strain of C. difficile?

* High rates of nosocomial infection | * Increased production of toxin

What is the superbug? Why is it so called?

Staphylococcus aureus Because it causes wound infections, food poisoning and is quite extensively resistant to antibiotics

How does C. difficile cause damage?

2 exotoxins: * Toxin A- enterotoxin -- fluid production, mucosal damage * Toxin B- extremely cytopathic -- ulceration

Describe the features of S. aureus | Where does it colonise?

Gram positive cocci Facultative anaerobe ``` Colonises: • URT • nose • skin • vagina • intestine ```

How does S. aureus colonise?

Adhesins

What are the virulence factors of S. aureus?

* Exfoliative toxins * Enterotoxins * Haemolysins * Lipases * Proteases * DNAases * Leukocidins * Protein A * Beta lactamase

Discuss antibiotic resistance with S. Aureus

This is a big problem because so many people are infected. 1/ Penicillin resistance quickly - has beta lactamase 2/ MRSA 3/ Starting to see vancomycin resistance

Is S. aureus hardy? | Why?

Yes, survives well in the environment | Able to form biofilms

Where does S. aureus cause disease?

* Endocarditis * Osteomyelitis Many, many more

Describe the genome of S. aureus

Core genome Accessory Genome Plasmids Pathogenicity island: • enterotoxins • superantigens

Describe the features of enterococci Where does it colonise?

Gram positive cocci | Commensal in gastrointestinal tract

What is VRE? | How did it come about?

Vancomycin resistance enterococci Years of vancomycin use in hospitals

Describe resistance of enterococci

``` Multiple antibiotic resistance: • penicillins • cephalosporins • aminoglycosides • vancomycin --> VRE ```

What infection is associated with bone marrow transplants?

Aspergillus mould

What is MRSA? How is it overcome?

Methicillin resistant S. aureus Big problem for HCAI MRSA now treated with vancomycin

What is MRSA? | How is it overcome?

Methicillin resistant S. aureus | Now use Vancomycin

Which enterococci cause nosocomial infection?

E. faecium | E. faecalis

What sort of infections are caused by enterococci?

* Abdominal infections * Urinary tract infection * Septicaemia

What are glycopeptides?

Antibiotics | eg. Vancomycin

Give an example of transmission via a vehicle

* Blood transfusion * Food * Water

Why are people of poor health more susceptible to Klebsiella?

In respiratory tract Poor health: • decreased fibronectin in RT • predisposition to Klebsiella colonisation

What is the most important feature of Clostridium difficile for its transmission?

Spore formation

Describe how broad spectrum antibiotics predisposes someone to C. difficile infection

1. BS antibiotics kill many bacteria in the GIT 2. C. difficile now has the opportunity to overgrow 3. Toxin production 4. Mild diarrhoea / P.M.C.

What is haematogenous spread?

Spread via circulating blood

What is osteomyelitis?

Infection & inflammation of the bone or bone marrow

Why should we worry about S. aureus antibiotic resistance?

Because bacteraemia due to S. aureus is common in Australia. | This is a serious infection.

Lecture 23 - Health Care Associated Infection Flashcards

(64 cards)