Healthcare Associated Infections Flashcards
What is a healthcare associated infection
What are the most common HCAIs
What are the most common causes
Infection occurring as a result of healthcare activity, not incubating at the time of initial healthcare exposure
48-72hours
Hospital acquired bacteremia UTIs Surgical site infection C diff HAP
Central IV/ urinary/peripheral catheter => bacteria binds to plastic
Why are hosts becoming more vulnerable to HCAIs
Invasive procedures Prosthetic/implantable devices Immunosuppression Obesity/diabetes/comorbidities Extremes of age
Why are organisms becoming more problematic in HCAIs
Widespread prolonged use of broad spec antibiotics
Why is the hospital environment a prime location for transmission
High occupancy Multiple bed moves Isolation facilities Invasive devices Environmental hygiene
Poor staffing ratios, infection control, hand hygiene
What are the characteristics of normal endogenous flora
- skin
- gut
- urogenital
Live on/in patient
-generally g+ve
Skin (resident)
- protective
- not easily removed
- cause infection via skin breaks
Skin (transient)
- loose attachement
- easy transfer, easy removal
- source of cross infection
Gut => inhibit other pathogens
- transient colonisation in stomach
- sparse in duodenum
- moderate in ileum
- large bowel, densely packed
Vaginal
-changes in relation to age, hormones, pH
Distal urethra
-sparse mix
How does endogenous flora cause infection?
Changes in flora due to changes in environment => becomes more G-ve
Endogenous flora go to areas of the body where they aren’t normally found
What exogenous pathogens often cause HCAIs?
Cdiff Pseudomonas Aspergillus S aureus Legionella Flu, norovirus, BBV
Describe the common methods of contact transmission
Direct => via colonised hands
Indirect => via colonised environment, fomites
- biofilms help bacteria persist in dry areas
- non porous surfaces transmit pathogens better
Line
-take blood culture from both IV and peripheral vein to establish if infection due to line
What are the most common cause of line infections
- non oncology
- oncology
- burns, neutropenic patient
- long term parenteral nutrition
Non oncology -coagulase negative staph -s aureus -non candida albican species enterococcus faecalis
Oncology (above plus)
- Ecoli
- E faecium
- viridans streptococci
Burns, neutropenic
- pseudomonas
- enterobacteriaceae
Long term parenteral nutrition
-candida
How would you prevent line infections
- at insertion
- after insertion
At insertion
- is it needed?
- ANTT, wash hands, clean site
After insertion
-daily line check, timely removal
When would you use soap and water over hand gel
Soap and water -spore forming pathogens (Cdiff on hands => unaffected by alcohol) -visibly soiled -after toilet
What are the most common causes of catheter associated UTI
Why is it hard to distinguish whether the UTI was HCAI or not?
Proteus
Klebsiella
Pseudomonas
Urinary catheter insertion can be traumatic => inflammation
- proteinuria
- haematuria
- leukocytes
What are the most common causes of HAP
When would you consider the possibility of a HAP
-what criteria would you like to meet
Strep pneumoniae
Staph aureus
G-ves (pseudomonas, haem influenzae)
48-72hour cut off to exclude incubation of microbes on admission
-consider in any readmission
Radiological evidence Purulent secretions => microbiological investigations Increased O2 needs Fever Leukocytotic or leukocytopenic
What are the common causes of environmental transmission
- food
- water
- equipment
- contaminated IV fluid
- air
Food
-salmonella, ecoli
Water
-legionella, cryptosporidium
Equipment (dust and biofilms, hard to clean)
- stenophomonas, pseudomonas
- acinetobacter, other G-ves
Air (poor ventilation)
-cryptococcus, aspergillus
Describe CDiff infections
-what are the risks associated with infection
4Cs in last 2 months
- cephalosporins
- co-amoxiclav
- clindamycin
- ciprofloxacin
- comorbidities and chemo
- antimotility agents/PPI
- major abdo surgery
- poor host IgG response
- burns
- old age
