Healthcare Acquired Infections Flashcards by G H

What is a healthcare acquired infection?

Infections that were not present or in the pre-symptomatic phase at the time of admission to hospital
Which arise > 48 hrs after admission or within 48 hrs of discharge

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What are the possible outcomes of HAI?

Extended length of stay, pain, discomfort, permanent disability, death
Increased Cost: 33% decrease in HAI in Scotland would lead to savings of £55 million (2007 National Prevalence Study)
Litigation
Loss of public confidence and decreased staff morale

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What are the most common sites of HAI?

UTI (related to catheterisation)
Surgical site infection
RTI (intubation)
Bloodstream infections (central venous catheters)
GI infection
Skin and soft tissue infections

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What is the relationship between humans and bacteria?

Approx. 10^14 bacteria in adult human
Approx 10 bacterial cells to every human cell
Human beings carry >1kg of bacteria in their gut alone
500 different species of bacteria have been isolated from human stool

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What are patients in hospital more vulnerable to?

Microbial colonisation and infection

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What is the most common form of staph aureus to be colonised with?

Meticillin sensitive staphylococcus aureus (MSSA)

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How can a colonising staph aureaus cause infection?

Break in skin e.g. surgical site infection
Vascular device e.g. PVC, CVC
Catheter associated urinary tract infection (CAUTI)
Ventilator associated pneumonia (VAP)

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What process leads to most HAI?

A disturbance in the bacterial-host equilibrium

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What microbial factors can tip the bacterial-host balance towards infection?

Increased

Resistance
Virulence
Transmissability
Increased survival ability
Ability to evade host defences

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What host factors can tip the bacterial-host balance towards infection?

Devices: PVC, CVC, Urinary catheter, Ventilation
Antibiotics
Break in skin surface
Foreign body
Immunosuppression
?Gastric acid suppression
Age extremes
Overcrowding
Increased opportunity for transmission e.g. Interventions, Hands!!!

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What is required for chain of infection?

Source of microbe (endogenous or exogenous)
Transmission
Host

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What means of transmission are there for infection?

Direct contact
-e.g. Staphylococcus aureus, coliforms

Respiratory/Droplet
-e.g. Neisseria meningitidis, Mycobacteria tuberculosis

Faecal-Oral
-e.g. Clostridium difficile, Salmonella sp.

Penetrating Injury
-e.g. Group A streptococcus, Bloodborne viruses

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How can the chain of infection be broken?

Risk awareness
Standard Infection Prevention and Control Precautions (SICPs)
Hand Hygiene
Appropriate PPE
Vaccination
Post Exposure Prophylaxis
Environment

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Cleaning

Physical removal of organic material and decrease in microbial load

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Disinfection

Large reduction in microbe numbers-spores may remain

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Sterilisation

Removal/destruction of ALL microbes and spores

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How should spread of infection be prevented with low risk objects such as stethoscopes, cots and mattresses which have been in contact with intact skin?

Cleaning compatible with manufacturer’s instructions

How should spread of infection be prevented with medium risk objects such as bedpans, vaginal specula and endoscopes which have been in contact with mucous membranes?

Disinfection or sterilisation as appropriate

How should spread of infection be prevented with high risk objects such as surgical instruments?

Sterilisation

How should cleaning of equipment be carried out?

Manufacturer’s instructions
Detergent and water
DRYING IS AN IMPORTANT PART OF THE PROCESS!
Cleaning essential PRIOR to disinfection and Sterilisation if these are required

What methods of disinfection are there?

Heat
Chemical-Steam under pressure (autoclave)
Gas (ethylene dioxide)
Ionising radiation

How can heat be used as a method of disinfection?

Pasteurisation (e.g. bedpans, linen, dishwashers)

- Boiling (vaginal specula, ear syringes)

How can chemical be used to disinfect items?

Chemicals vary in their organism activity range
Needs to be equipment compatible
Examples: Alcohol, chlorhexidine, hypochlorites, hydrogen peroxide

How is local surveillance carried out for infection control?

Lab based

- Ward/clinical area based

What types of surveillance are there for infection control?

- Local surveillance | - National surveillance

Give examples of national surveillance which has taken place in Scotland for infection control.

- MRSA bacteremia - MSSA bacteremia - Clostridium difficile - Surgical Site Infections - E coli bacteremia ?

Infection outbreak

An outbreak of an infection is defined as 2 or more cases of a infection linked in time and place.

What is the purpose of IPCT?

Prevent individual infections and surveillance

What is the purpose of surveillance?

Detect and identify a possible outbreak at the earliest opportunity

How are outbreaks identified?

- Have to act on suspicion | - Typing necessary to determine if the same strain present i.e. an outbreak

How can infections be typed?

- Antiobiogram (antibiotic sensitivity pattern) - Phage typing (e.g. Staphylococcus aureus) - Pyocin typing (Pseudomonas) - Serotyping (Salmonella, Pseudomonas) - Molecular typing (DNA typing)

What control measures are there for infection outbreaks?

- Single room isolation - Cohorting of cases - Clinical Area/Ward Closure - Re-inforcement of IPC measures - Staff exclusion (e.g. colonised staff in case of MRSA; non-immune staff in case of VZV, measles etc.) - Staff decolonisation or other measures

What are the clinical characteristics of C diff. infection?

- Diarrhoea - Faeces have a characteristic odour - May have abdominal pain, pyrexia, raised white cell count - Pseudomembranous colitis (PMC)=most serious form

Why is C.diff do prominent?

- Part of the normal gut flora in ~2% adults - Carriage rate increases with age - ~30% elderly are colonised - Can survive in environment - importance of cleaning

What does C.diff produce?

- 2 toxins | - Toxin negative strains DO NOT cause disease

Who are more susceptible to C. diff?

Elderly men

What does C.diff cause?

Imbalance in gut flora

How is C.diff infection diagnose?

- Positive toxin test does not always mean disease | - Diarrhoeal symptoms NEED to be present for diagnosis of CDI

Why does C. diff. infection still occur?

- Not possible to prevent all cases - All antibiotics can predispose to CDI although some are more predisposing than others - New strains? - Less handwashing because more handgelling? - Environmental contamination may still be an issue? - Increased no. of vulnerable patients close together? - Increased throughput of patients? - Other drugs having an effect e.g. PPIs?

What is the treatment for C.diff infection?

STOP THE ANTIBIOTICS PREDISPOSING TO C difficile IF POSSIBLE! If symptomatic, treatment: - Oral metronidazole - Oral vancomycin if severe or failure to improve on metronidazole - Oral fidaxomicin if 2nd episode

Use of what 4 antibiotics should be reduced to reduce C diff infections?

- Ceftriaxone (other cephalosporin's) - Co-amoxiclav - Clindamycin - Ciprofloxacin (Other quinolones)