Healthcare Acquired Infections Flashcards
What is a HAI? [2]
-infections that were not present or in the pre-symptomatic phase at time of admission -which arise at least 48h after admission or within 48h of discharge
Possible outcomes of a HAI? [4]
- extended length of stay, pain, discomfort, permanent disability, death
- increased costs
- Litigation
- loss of public confidence and decreased staff morale
What are most common sites of HAI? What in the healthcare context can cause these? [6]
>UTI: catheterisation
> Surgical site infection
>Respiratory tract infection: intubation
>Blood stream infections: central venous catheters
>GI infection
>Skin and soft tissue infection
Are people colonised by Staph Aureus? % and what strain
Yes. Approx. 30% are colonised. Most are colonised with Meticillin Sensitive Staph Aureus (MSSA)
Colonised Staph Aureus can also cause infection how? [4]
>Break in skin eg surgical site infection
>Vascular device (eg PVC, CVC)
>Catheter associated UTI
>Ventilator associated pneumonia
What are microbial factors tipping balance towards infection? [5]
Increased
>resistance
>virulence
>transmissability
>Inc survival ability
>ability to evade host defences
What are host factors tipping balance towards infection? [7]
>devices eg CVC, catheter, ventilation
>antibiotics
>break in skin surface
>foreign body
>immunosuppression
>age extremes >overcrowding
What are the means of transmission? [4] Give an example of an organism which you can be infected by for each transmission mode
>Direct: staph aureus
>Respiratory: Neisseria meningitidis, mycobacterium tuberculosis
>Faecal-oral: C Diff
>Penetrating injury: Group A streptococcus, blood borne viruses
How can you ‘break the chain’ of infection? (Microbe source, transmission, host) [6]
- risk awareness
- standard infection prevention and control precautions
- hand hygiene
- appropiate PPE
- vaccination
- post exposure prophylaxis
What is: >cleaning >disinfection >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
Name 3 instruments that come with low risk of HAI and how do we reduce this risk?
From intact skin contact:
- Stethoscope -cots
- mattresses
Reduce risk by washing frequently
- detergent and water; drying
Name 3 instruments that come with medium risk of HAI and how do we reduce the risk? [2]
- bedpans
- vaginal specula
- endoscopes
Reduce risk by pasteurisation, boiling (heat), alcohol, chlorhexidine, bleach (chemical means)
Name instruments that come with high risk of HAI and how do we reduce the risk? [4]
-surgical instruments
Reduce risk by autoclave, hot air oven, gas, ionizing radiation
Discuss features of cleaning equipment [3]
- use detergent of water
- drying is important part of process
- cleaning essential prior to disinfection and sterilisation
What are methods of disinfection? 2 ways
Heat
>Pasteurisation (eg bedpans, linen, dishwashers)
>Boiling (eg vaginal specula, ear syringes)
Chemical
>eg alcohol, hydrogen peroxide
What are methods of sterilisation? [4]
>steam under pressure
>hot air oven
>gas (ethylene dioxide)
>ionising radiation
What different surveillance types exist for disinfection of equipment?
- Local
- National
Define an outbreak?
2 or more cases of an infection linked in time and place
How do you go about identifying outbreaks?-have to act on suspicion Typing is necessary to determine if strain is present. Name 5 typing methods
-typing methods (necessary to determine if same strain present):
>antibiogram
>phage typing
>pyocin typing
>serotyping
>molecular typing
What are control measures for outbreaks? [6]
>Single room isolation
>Case cohorting
>Clinical ward closure
>Re-inforcement of IPC measures
>Staff exclusion
>Staff colonisation
C. Diff infection clinical features? [4]
- diarrhoea
- faeces have characteristic colour
- abdominal pain, pyrexia, raised WCC
- pseudomembranous colitis
Describe pathophysiology of C.diff [3]
Enterotoxin (A) and cytotoxin (B) which is inflammatory Toxin negative strains of C. Diff do not cause disease!
What does C. diff infection arise from? What complication can arise if untreated and pseudomembranous colitis is present?
Imbalance in gut flora, either endogenous or exogenous source. Underdiagnosed in community Cx: toxic megacolon
How is C. Diff infection diagnosed? What are investigations to order? [3]
Positive toxin test AND diarrhoeal symptoms
- FBC: leucocytosis
- Sigmoidoscopy: tissue culture
- Stool: culture and ELISA or PCR to detect C. diff toxins
Why is C. Diff infection still occurring?
- cant prevent all cases
- antibiotics can predispose to CDI
- new strains?
- environmental contamination may be issue
- Inc number of vulnerable patients close together
Treatment of C. diff infection [7]
- stop precipitating antibiotics
- if symptomatic, give:
>oral metronidazole
>oral vancomycin if severe
>oral fidaxomycin if 2nd episode
- dont treat if symptom free, can cause CDI (C diff infection)
- Stool transplants
What are the 4C’s we should avoid to reduce CDI? [4] Other methods of prevention [3]
- cephalosporin -co-amoxiclav -clarithromycin -ciprofloxacin
1. Follow Antimicrobial Management Team and local antibiotic policy
2. Isolate symptomatic patients
3. Wash hands between patients
What does MRSA stand for?
Methicillin resistant staphylococcus aureus
MRSA Ix - describe how you would screen What to do if there’s active infection? [2]
- Screening of carriers by nasal swab
- Active infection: swab the affected site and take blood culture
MRSA Mx of asymptomatic carriers [2] Mx of active infection [3]
- Asymptomatic carriers:
- MUPIROCIN 2% in white soft paraffin 4x daily for 5 days
- CHLORHEXIDINE GLUCONATE applied all over body with particular attention to axilla, groin and perineum once daily for 5d - Active infection: VANCOMYCIN, TEICOPLANIN or LINEZLOID
Grampian C.diff severity markers [6]
- Temperature > 38.5
- Consider severe co-morbidities and immunodeficiency
- Suspicion of pseudomembranous colitis, toxic megacolon, ileus
- Evidence of severe colitis on CT scan/x-ray
- WBC >15x10^9 cells/L
- Acute rising creatinine >1.5x baseline
What is Giotra’s triad and what is its connection to C.diff?
Increasing abdominal pain, abdo pain, distension Leukocytosis >18000 Haemodynamic instability Risk factor
What is ESBL?
Extended Spectrum Beta Lactamases
Ax: E. coli producing extended spectrum beta lactamases, usually causing UTIs
How does ESBL present?
Ix Mx
Mx: second line
Presentation: UTI Ix: Urine MC&S
Mx:
Nitrofurantoin + patient isolation
- Fosfomycin
SSI
Causative organisms [4]
Investigations Mx
Ax:
- staph aureus (also coagulase -ve staph (e.g. staph epidermidis)
- strep
- pseudomonas, E. coli
- Enterobacter, fungi, anaerobes)
Ix: pus or infective tissue cultures (aim for deep structures as opposed to superficial swabs)
Mx: ab according to C&S
SSI Procedural Risk factors [4]
- shaving wound using razor (disposable clip preferred)
- non-iodine impregnated incise drape
- tissue hypoxia
- delayed administration of prophylactic abx in tourniquet surgery
- use of diathermy for skin conditions
Prevention of SSI
Pre-op [3]
Intra-op [2]
Post-op
• Pre-op:
- no routine body hair removal (if rqd use electrical clipper with single use head)
- abx prophylaxis if placement of prosthetic valve
- clean contaminated or contaminated surgery (aim to give single dose of IV abx on anaesthesia or earlier if tourniquet to be used)
• Intra-op:
- prep skin within alcoholic chlorhexidine
- cover surgical site with dressing
• Post-op: tissue viability advice for surgical wounds healing by secondary infection
Cellulitis Define Ax [2] Features [3]
- Inflammation of skin and subcutaneous tissues
- Typically due to Streptococcus pyogenes or Staphylcoccus aureus
Features:
- commonly occurs on the shins
- erythema, pain, swelling
- there may be some associated systemic upset such as fever
Cellulitis Eron classification [4]
Cellulitis Criteria for admission [6]
- Has Eron Class III or Class IV cellulitis.
- Has severe or rapidly deteriorating cellulitis (for example extensive areas of skin).
- Is very young (under 1 year of age) or frail.
- Is immunocompromized.
- Has significant lymphoedema.
- Has facial cellulitis (unless very mild) or periorbital cellulitis.
Cellulitis mx for: - Mild-moderate - Other options? [3] - Pregnancy - Severe [2]
Mild-moderate: Flucloxacillin
Option: clarithromycin, erythromycin (pregnancy) , doxycycline
Severe: co-amoxiclav, cefuroxime
Osteomyelitis
Define
Ax
Ix
Osteomyelitis describes an infection of the bone.
Staph. aureus is the most common cause Ix: MRI
When can a trial of ab prophylaxis be considered? [2]
How long a review should be arranged?
What antibiotic would be first line?
- Hospital admission for 2 separate eps of cellulitis/erysipelas
- In previous 12m
- Review antibiotic prophylaxis for recurrent cellulitis or erysipelas at least every 6 months
- Phenoxymethylpenicillin
What is OPAT? [3]
Outpatient parenteral antimicrobial therapy (OPAT)
- administration of parenteral antimicrobial therapy without intervening hospitalization.
- Less visits to hospital, reduced HAIs
Eligibility criteria for OPAT
