Outbreak Flashcards
What is a Healthcare Associate Infection?
An infection one might get from a healthcare setting: hospitals, care homes, doctors’ surgeries, health centres or receiving care at home
Most common types: UTI, infections following surgery, skin infections, sickness and diarrhoea
What is a hospital acquired infection?
Generally an infection acquired after being in hospital for more than 48 hours or within 48hrs of discharge
This is dependant on the organisms incubation period
Most common causes of hospital acquired infections?
- UTI = 22%
- Surgical site = 18.6%
- Respiratory = 17.5%
- Bloodstream = 10.8%
- GI = 6.8%
- Skin and soft tissue = 4%
What is the most common cause of a hospital acquired UTI?
Catheterisation
What is the most common cause of a hospital acquired respiratory tract infection?
Intubation accounts for almost a 1/4 of these
What is the most common cause of a hospital acquired bloodstream infections?
Many Central Venous Catheter related
What is the definition of an outbreak?
An outbreak of an infection is defined as 2 or more cases of an infection linked in time and place
What is the purpose of IPCT and surveillance?
1) Prevent individual infections, as well as outbreaks
2) Detect and identify possible outbreaks at the earliest opportunity
What is the “chain of infection”?
1) Portal of entry
2) Susceptible host
3) Infectious agent
4) Reservoir
5) Portal of Exit
6) Mode of transmission
Start again:
1) Portal of entry
2) Susceptible host
etc
What are examples of infectious agent classes in the “chain of infection”?
Bacteria
Virus
Fungi
Prions
What are examples of reservoirsin the “chain of infection”?
Humans Equipment Environment Food Animals
What are examples of portal of exit in the “chain of infection”?
- Blood and body fluids
- Skin scales/wound
- Coughing and sneezing
What are examples of mode of transmission in the “chain of infection”?
- Direct or indirect
- Inhalation
- Ingestion of contaminated food
What are examples of portal of entry in the “chain of infection”?
- Skin/surgical wound
- Eyes
- Mouth
- Respiratory tract
- Intestinal tract
- Tubes
What are examples of susceptible hosts in the “chain of infection”?
- Underdeveloped immune system
- Decreasing immune system
- Drugs
- Diseases
- Tubes
How can you break the chain of infection in terms of: Contact, ingestion or inhalation?
- Hand hygiene
- Personal protective equipment
- Food safety
- Cleaning, disinfection and sterilisation
- Isolation
When should hand hygiene be implemented?
1) Before touching a patient
2) Before clean/aseptic procedure
3) After touching a patient
4) After exposure to body fluids risk
5) After touching patients surroundings
How can you break the chain of infection in terms of reservoirs: humans, equipment, animals, soil, water etc?
- Cleaning, disinfection and sterilisation
- Infection prevention policies
- Pest control
How can you break the chain of infection in terms of portal of entry: broken skin/incision, respiratory tract, mucous membranes, catheters and tubes?
- Hand hygiene
- Personal protective equipment
- Personal hygiene
- First aid
- Removal of catheters and tubes
What percentage of HAI are SSI?
15.9%
What percentage of acute adult inpatients have a SSI?
0.8%
What is the median age of an SSI?
63 years
What is the most common event leading to a SSI?
Surgery (80.5%) - Most commonly general surgery (40.4%)
What is the most common causative agents of an SSI?
1) S aureus = 23.9%
2) E coli = 14.1%
3) Anaerobes = 8.5%
4) Other = 53.5%
What percentage of those with SSI have life limiting or end of life prognosis?
28.7%
What are the most common prescribed antimicrobials used to treat SSIs?
- Flucloxacillin
- Vancomycin
What are the most common prescribed antimicrobials used to prevent SSIs?
- Gentamicin
- Cefuroxime
- Co-amoxiclav
What percentage of antimicrobials were prescribed to treat SSIs?
3.2%
What are SSIs most likely to lead to ?
Deep tissue or organ space infection - 52.8%
How can you break the chain of infection in terms of susceptible hosts?
- Immunisation
- Treatment of the underlying disease
- Health insurance
- Patient education
How can you break the chain of infection in terms of portal of exit?
- Hand hygiene
- Personal protective equipment
- Control of aerosols and splatter
- Respiratory etiquette
- Waste disposal
How can you break the chain of infection in terms of transmission based precautions - Contact?
1) Hand hygiene before entering room
2) Personal protective clothing
- Gloves
- Apron
3) Keep door closed
4) Before leaving:
- Decontaminate equipment
- Discard gloves/apron in appropriate waste bins
- Decontaminate hands
How can you break the chain of infection in terms of mode of transmission?
- Hand hygiene
- Personal protective equipment
- Food safety
- Cleaning, disinfection and sterilisation
- Isolation
How can you break the chain of infection in terms of transmission based precautions - Droplet?
1) Hand hygiene before entering room
2) Personal protective clothing, before entering:
- Gloves
- Apron
- Fluid resistant surgical mask
- Eye/facial protection
3) Keep door closed
4) Before leaving:
- Decontaminate equipment
- Discard protective clothing in appropriate waste bins
- Decontaminate hands
How can you break the chain of infection in terms of infectious agent?
- Early diagnosis and treatment
- Antimicrobial stewardship
How can you break the chain of infection in terms of transmission based precautions - airborne?
1) Hand hygiene before entering room
2) Personal protective clothing, before entering:
- Gloves
- Apron
- FFP3 respirator
- Eye/facial protection
3) Keep door closed
4) Before leaving:
- Decontaminate equipment
- Discard gloves, apron/gown and eye/facial protection in appropriate waste bins
- Decontaminate hands
5) After leaving:
- Remove FFP3 respirator and discard in appropriate waste bin
- Decontaminate hands
What is a droplet?
- > 5um
- Spread assumed to be about 1 metre
- Drop to ground
What is an aerosol?
- <5um
- Much more widespread than a droplet
- Remain suspended in the air
What type of infection are more highly transmissible?
Airborne spread infection are more highly transmissible and therefore require different precautions
What is the limit to the human eye in visibly seeing a droplet?
40um
What is cleaning?
Physical removal of organic material and decrease in microbial load
What is disinfection?
Large reduction in microbe numbers - spore may remain
What is sterilisation?
Removal/destruction of ALL microbes and spores
What are low risk in terms of HAI and what precaution is used?
Low risk = Intact skin contact e.g. stethoscope, cots, mattresses
Precautions = Cleaning compatible with manufacturers instructions
What are medium risk in terms of HAI and what precaution is used?
Medium risk = Mucous membrane contact e.g. bedpans, vaginal specula, endoscopes
Precautions = Disinfection or sterilisation If possible
What are high risk in terms of HAI and what precaution is used?
High risk = Surgical instruments
Precautions = Sterilisation
Important things to follow during cleaning??
- Follow manufacturer’s instruction
- Detergent and water
- Drying is important!
- Cleaning is essential prior to disinfection or sterilisation
Methods of disinfection?
1) Heat:
- Pasteurisation e.g. bedpans, linen, dishwashers
- Boiling e.g. vaginal specula, ear syringes
2) Chemical
- Chemicals vary in their organism activity range
- Needs to be equipment compatible
- Examples = Alcohol, chlorhexidine, hydrochlorites, hydrogen peroxide
Methods of sterilisation?
- Steam under pressure = Autoclave
- Hot air oven
- Gas (Ethylene dioxide)
- Iodising radiation
What are the important aspect of surveillance in infection?
Local:
- Laboratory based
- Ward/clinical area based
National surveillance
All healthcare workers
Approx how many bacteria cells to every human cell in the body?
10
How many bacteria in the human body?
10^14 in an adult human
How many different species of bacteria have been isolated from human stool?
500 different species of bacteria
Examples of outbreaks?
- MRSA
- MSSA
- Clostridium difficile
- Surgical site infections
- E coli
Colonisation versus infection example, S aureus?
Approx 30% of the population are colonised with S aureus in their nose yet do not have infection
How can S aureus go from colonisation infection?
S aureus acts as an opportunistic bacteria and will cause in infection if there is:
- Break in the skin
- Vascular device
- Catheter
- Ventilation
Which microbial factors can encourage infection over colonisation?
Increased:
- Resistance
- Virulence
- Transmissability
- Increased survival ability
- Ability to evade host defences
Which host factors can encourage infection over colonisation?
- 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, - Bad hand hygiene!!!
What is the effect of a silk suture presence in terms of infection risk?
Drastically increases the risk, demonstrated by Elek and Conon, 1957 - SA inoculated into foreman’s of medical students:
- 6.5 million bacteria required to cause infection without suture
- Only 100 bacteria required when silk suture was present
Examples of bacteria that take advantage of direct contact?
Staphylococcus aureus
Coliforms
Examples of bacteria that take advantage of Respiratory/droplets?
Neisseria meningitides
Mycobacteria tuberculosis
Examples of bacteria that take advantage of faecal-oral route?
Clostridium difficile
Salmonella sp.
Examples of bacteria that take advantage of penetrating injuries?
Group A Streptococcus
Bloodborne viruses
Which typing methods may be used in identifying the cause of an outbreak?
- Antibiogram (Antibiotic sensitivity pattern)
- Phage typing (e.g. S aureus)
- Pyocin typing(Pseudomonas)
- Serotyping (Salmonella, Pseudomonas)
- Molecular typing (DNA typing)
What control measures can be used to halt an outbreak?
- Single room isolation
- Cohorting of cases
- Clinical area/ward clousre
- Re-infrocement of IPC measures
- Staff exclusion (e.g. colonised staff in case of MRSA; non-immune staff in case of VZC, measles etc)
- Staff decolonisation or other measures
Characteristics of C difficile?
- Diarrhoea
- Faeces have a characteristics odour
- May have abdominal pain, pyrexia, raised WBC
- Pseudomembranous colitis
Testing C difficile?
Positive toxin tes - although this does not always mean disease
How to treat C difficile?
1) Oral metronidazole
2) If severe or does not respond to metronidazole –> Oral vancomycin
3) Oral fidaxomicin if 2nd episode
