W4: Health care associated infections Flashcards
How does WHO define a health care-associated infection?
An infection occurring in a patient during the process of hospital care or other health environment that was not present or incubating at the time of admission.
What are the consequences of health care associated infections?
Prolonged hospital stays
Long term disability
Increased resistance to antimicrobials
Additional costs for health systems
Financial and emotional costs for patients and their family
Avoidable deaths
How common are HCAIs?
Found in 7.1% of patients in acute care hospitals
30% of patients in ITU’s
What are the most common types of health care-associated infections?
Respiratory
Urinary Tract Infections
Surgical Site infections
Clinical sepsis
GIT e.g C.diff
Blood stream infections
What are the health care associated risk factors for health care associated infections?
Prolonged hospital admissions
Haemodialysis
Immunsuppression e.g in chemotherapy
Antibiotics within the last 90 days - risk of C.Diff and Candida. alibicans after penicillin causing thrush
Intensive Care Stay
Invasive Devices such as lines, catheter and ventilator
What patient factors increase the risk of health care associated infections?
Extremes of age
Immobility
Chronic illness e.g diabetes, COPD, obesity
Pre-existing colonisation with bacteria such as MRSA and C.Diff
How do gram negative bacteria tend to enter the body?
respiratory and urinary routes e.g intubation, poor vough responsice, catheters
Catheter - UTI and pneumonia.
How do gram positive bacteria tend to enter the body?
Tend to cause skin and soft tissue infections
Enter the body by cannulas, pressure sores and surgical sites.
What are the different routes by which pathogens can enter the body?
Intubation - often coupled with porr ventilation/cough response
Cannula/lines
Antibiotic associated infection
Catheter
Wound drains
Surgical incisions
Physical contact
What are the most common modes of transmission of HCAIs in the NHS?
Contact - from hands, equipment or other environment
Air-borne
Blood born is very very rare.
What is meant by an endogenous or an exogenous source of infection?
Endogenous - from patients own microflora - this is the most common type of HCAIs.
Exogenous - from external sources such as a contaminated surrounding environment or cross transmission
What is the difference between colonisation and infection?
How does this apply to HCAIs?
Colonisation - present on surface, no harmful effects, may even provide benefit. Most opportunistis infections are part of normal flora on skin or mucosa
Infection - causes disease - harmful tot he host
How can microbes change from colonisation to a biofilm (infection)?
Link to HCAIs
Planktonic pathogen (microbe on its own) adheres to a surface this is originally reversible.
Produces an extracellular matrix and proliferates to form a monolayer. ECM will contain polysaccharides, structural proteins and nucleic acid.
Process continues and a multi-layer microcolony forms, grows in three dimeinsation and cell to celll communication begins (adhesion is now irreversible)
A mature biofilm forms from a polysaccharide mesh, a characteristic mushroom-shape.
Some cells may detach and disperse into the environment as planktonic cells to potentially start a new cycle of biofilm formation.
Why is biofilm formation beneficial to bacteria?
More difficult to treat with antibiotics
Close proximity allows - metabolic substrate and products echange, this allows different species within the biofilm to support each other.
What are the most common gram postive bacteria causing hospital acquired infections?
Staphylococcus aureus (MRSA MSSA)
Enterococcus faecalis faecium
Coagulase negative Staphylococcus
C.diff
What are the most common gram negative pathogens causing HCAIs?
Escherichia coli
Klebsiella spp.
Pseudomonas aeruginoase
What are the most common viruses causing hospital acquired infections?
Influenza viruses
Norovirus
Blood born viruses such as Hepatitis,HIV (Not very common)
What are the most common fungi to cause HCAIs?
All of these are most common in immunocompromised individuals
Candida Albicans
Asperigillus spp.
These can present as yeast or mold form (produce spores)
What type of infection are staphylococcus aureus and streptococci most associated with?
Skin and soft tissue infections
What type of infection are C.Diff most associated with?
Intestinal bacteria - GIT
Can often cause pseudomembrane colitis and toxic megacolon.
What type of infection are gram negative bacteria such as enterobacteriaceae associated with?
Respiratory and urinary tract infections
What type of infection is pseudomonas aeruginosa associated with?
Opportunistic bacteria
Common in immunocompromised and ventilated patients
Can cause infections of any type
Easy identifiable do to greenish appearance
Why is microbial confirmation of an infection important?
Confirms infection
Identifies cause
Guides appropriate treatment
What are the different type of samples that may be used to identify a pathogen?
MRSA screen
Sputum sample
Skin Swab
Stool Sample
Urine Sample
Drain Fluid
Wound swab
Blood sample - negative and positive bottles
Why is the timing of identification of an infection important?
Easier and more effective intervention
E.g surgical site after knee surgery early give antibiotics late prosthetic must be removed.
Why are catheters associated with an increased risk of UTIs?
Bacteria colonise the plastic of the catheter (biofilm formation)
Allow to bypass the body defense mechanisms such as the protective urethral sphnicter
The longer the catheter is in place the more likely bacteria are found in the urine
What is the treatment for a catheter associated UTI?
Remove the source of infection (catheter)
Antibiotics based on culture results - must be a longer than normal course 7 rather than 3 days.
What are the risk factors for health care associated pneumonia?
Ventilation, immobility (lack of exercise weakens respiratory muscles), reduced cough, aspiration, age
What is important to remember when diagnosis potential hospital acquired pneumonia?
Can be hard to distinguish from heart failure and other conditions
In winter viral causes such as influenza and covid are more common - try to avoid simultaneous infection.
What are the most common causes of hospital acquired pneumonia?
Tends to be gram negative and antibiotic resistant bacteria than community acquired
Examples of pseudomanonas, E.coli and Klebsiella.
What are the impacts of antibiotic usage of HCAI?
Exterts a strong selective pressure on normal microbial flora - selects for more resistance bacteria such as C.Diff potentially causing resistant outbreaks
What are the effects of antimicrobial resistance for the patient?
Delays in effective treatment
More toxic antibiotics required
Longer hospital stays
Increased mortality.
What are some of the methods used to prevent HCAIs?
Screening of patients :MRSA
isolation of patients with or ar high risk
Hygeine - hands and environment
Surgery - prophaylatic antibiotics
Hydrogen peroxide machine to kill microbes as cleaning procedure
UV light machine as a cleaning procedure to kill microbes.
What are some of the different infections patients are screened for?
All patients are screened for MRSA.
COVID - for elective surgical admissions and anyone who develops symptoms in hospital
High risk patients will also have a culture faeces for C.Difficle and PCR for multi-drug resistant gram negative bacteria.
What is an outbreak?
Two or more cases of the same infection realted in time and place, with evidence of transmission
in Exceptional cases a single case of a certain notifiable diseases would be managed as an outbreak e.g legionella.
What are the most common outbreaks in hospitals in winter?
COVID
INfluenze
Norovirus
What are the impacts of infection outbreaks in hospitals?
Bed closures
Increased hospital stays
Increased morbidity and mortality
Healthcare costs.
Why are respiratory infections more problematic in hospital now post COVID?
Individual patient: Risk of simulataneous infections, more than doubles mortality
Combined spikes of COVID and Flu numbers leads to overwhelemed hospitals and lack of resources.
What is the presentation of monkey pox?
High risk infection
Skin lesions - pustules that may become scabbed found on hands, axillary and genital area
Higher prevalence in MSM population.
What are some ways in hospital of preventing the spread of high risk infections?
Identifying high risk cases as soon as possible
Isolate individuals for further assessment
Staff to wear enhanced PPE
Rapid and effective treatment and notification of relevant authorities
What are the screening questions asked to identify high risk infections at A&E?
Have you travelled abroad in the last 21 days?
Do you have a fever or other symptoms of infection?
Yes to both indicates a potentially high risk foreign infection.
What blood stream infections is reporting manduatory for?
MSSA and MRSA
C.Diff (also when not in blood stream)
E.coli, Klebsiella and Pseudomonas
Why do hospitals need to record the numbers of certain infections?
Monitor rates against baseline
Compare to other organisations
Government targets
Penalties for excessive numbers
Compare control stratergies between organisms.
What are some successes in recent past in North East for control on HAIs?
Decreased C.diff rates - 20% of what they were in 2001 in 2014
Decreased usage of gram negative antibiotic usage since 2014.
