Healthcare Acquired Infeciton Flashcards
What are healthcare acquired infections?
Healthcare Associated Infections (HAI) are:
– 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
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
What are the common sites for healhcare associated?
UTI - mainly related to catheterisation
Surgical Site Infection
Respiratory tract infection (related to intubation)
Bloodstream infections - mainly central venous catheter related
GI infection
Skin and soft tissue infection
What are nature’s defence mechanisms?
Intact skin
Bacterial flora on the skin and the GIT
Body secretions (tears containing antibodies / enzymes, coughing)
Gastric acid
Flushing (urination)
2nd line defence (immune system)
Colonisation of the nose with staph aureus is said to be as common as 30% in the population. Describe the sensitivity of the staph aureus?
¨Most colonised with the METICILLIN SENSITIVE Staphylococcus aureus (MSSA)
How can the colonising staph aureus 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)
Disturbance in bacterial-host equilibrium leads to most HAI
What microbial factors can increase the chances of infection?
Increased:
- Resistance
- Virulence (the severity or harmfulness of a disease or poison)
- Transmissability
- Increased survival ability
- Ability to evade host defences
What are the host factors that can increase the chances of 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!!!
What is the chain of infection
Source of microbe (endogenous or exogenous)
Transmission
Host
What are the modes of transmission and give an example of each
Direct contact - staph aureus and coliforms
Respiratory / droplet - Neisseria meningitidis, mycobacterium TB
Faecal oral route - clostridium difficile, salmonella sp
Penetrating injury - group A streptococcus, bloodbourne viruses
How do we break the chain of infection?
Risk awareness
Standard Infection Prevention and Control Precautions (SICPs)
Hand Hygiene
Appropriate PPE
Vaccination
Post Exposure Prophylaxis
Environment
What is cleaning, disinfection and sterilisation?
Cleaning: Physical removal of organic material and decrease in microbial load
Disinfection: Large reduction in microbe numbers - spores may remain
Sterilisation: Removal/Destruction of ALL microbes and spores
What items are cleaned, disinfected and sterilised?
Low risk = cleaning
Intact skin contact e.g.
stethoscopes, cots,
Mattresses
Medium risk = Disinfection or sterilisation as appropriate
Mucous membrane
contact e.g. bedpans,
vaginal specula,
Endoscopes
High Risk = Sterilisation
e.g. surgical instruments
Cleaning is often required before sterilisation and disinfection
Drying is an important part of the process
What are the methods of disinfection?
Heat
–Pasteurisation (e.g. bedpans, linen, dishwashers)
–Boiling (vaginal specula, ear syringes)
Chemical
–Chemicals vary in their organism activity range
–Needs to be equipment compatible
–Examples: Alcohol, chlorhexidine, hypochlorites, hydrogen peroxide
What are methods of sterilisation?
Steam under hot pressure (autoclave)
Hot air oven
Gas (ethylene dioxide)
Ionising radiation
Surveillance
Local Surveillance:
–Laboratory Based
–Ward/Clinical Area Based
National Surveillance
What does IPCT stand for?
Infection prevention and control team
Local surveillance can either be lab based or clinical area based, what is the advantages and disadvantages of each?
Laboratory detects an organism and notifies IPCT and clinicians Advantages = know what organism is and specific recommendations can be made.
Disadvantages = depends on samples being sent, time taken to detect organism, tests not 100% accurate
Clinical area staff notify infection prevention and control team (IPCT)
Advantgaes - detect potential problem sooner, can ensure correct samples sent
Disadvantages - causative microbe not konwn, IPC measure need to be more general
What is the definition of an outbreak?
2 or more cases of an infection linked in time and place
What is the purpose of IPCT?
Prevent individual infections and outbreaks
What is the purpose of surveillance?
To detect and identify a possible outbreak at the earliest opportunity
Why is typing necessary?
To determine if the same strain present - (assessing if infections are linked and therefore classed as an outbreak)
What are the methods of typing?
–Antiobiogram (antibiotic sensitivity pattern)
–Phage typing (e.g. Staphylococcus aureus)
–Pyocin typing (Pseudomonas)
–Serotyping (Salmonella, Pseudomonas)
–Molecular typing (DNA typing)
What are control measures for outbreaks?
Single room isolation
Cohorting of cases
Clinical area/ward closure
Re-inforcement of IPC measures
Staff exclusion (colonised staff in case of MRSA, non-immune staff in the case of VZV, measles etc)
Staff decolonisation or other measures
So there are changes to the ward (it closes and people are kept in isolation)
There are changes to the staff (exclusion and decolonisation)
And cohorting of cases
What are the characteristic clinical features of c difficile?
Diarrhoea
Faeces have a characteristic odour
May have abdominal pain, pyrexia, raised white cell count
Pseudomembranous colitis (PMC)
How common is c Diff in the population?
Part of the normal gut flora in ~2% adults
Carriage rate increases with age
30% elderly are colonised
What causes c diff infection?
Imbalance in gut flora
Endogenous and exogenous source
2 toxins are produced - toxin negative strains do not cause disease
What is required for diagnosis of c diff?
Positive Toxin Test DOES NOT ALWAYS MEAN DISEASE!
Diarrhoeal symptoms need to be present for diagnosis of CDI!
What are factors increasing the likelihood of cdiff infection?
Antibiotics - all can predispose to CDI although some are more predisposing than others
Less handwashing because more handgelling
Other drugs having an effect such as PPIs
What is the treatment for CDiff?
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 (Scottish Medicines Consortium (SMC) Guidance 2012)
N.B. DO NOT TREAT THE SYMPTOM FREE!
Any antibiotic can cause CDI including Metronidazole and Vancomyin
