Hospital Acquired Infections And Adaptive Immune System Flashcards
What is a hospital acquired infection?
Infections arising as a consequence of providing health care
The infection was not present or incubating on admission
Onset at least 48 hours after admission
What are the commonest types of hospital acquired infections?
UTIs
GI problems
Surgical wound infections
Name some viruses that were/are notorious for hospital spread and state which have available vaccines
HepB (vaccine)
Norovirus
Influenza (vaccine)
Chicken pox (vaccine)
Give examples of common bacteria causing HAQ infection
Staph aureus (inc MRSA) Clostridium difficile E-coli Klebsiella pneumoniae Pseudomonas aureginosa
Name some features of clostridium difficile
Gram positive
Anaerobic
Produces spores - can survive for months in a clinical environment
Give some risk factors for HAQ infection
Extremes of age Obesity/malnourished Diabetes Cancer Immunosuppressed Smoker Surgical patient Emergency admission
What are the 4 Ps of infection prevention and control?
Patient
Pathogen
Practice
Place
Name some interventions we do for the patient to reduce change of HAQ infection
Optimise pt conditions (good nutrition, controlled diabetes) Antimicrobial prophylaxis Skin preparation Hand hygiene MRSA screens Disinfectant body wash
Give 2 methods of ward deep cleaning and explain why they are impractical
Steam cleaning
Hydrogen peroxide vapour
Difficult because need whole wards clear of people for days at a time
Describe the I-Five pathway for dealing with HAQ infections
Identify (A-F) Isolate Investigate Inform (infection control/other HCPs) Initiate (appropriate treatment)
What does the A-F stand for when trying to identify HAQ infections?
A - abroad (travel Hx) B - blood borne infections C - colonised D - diarrhoea/vomiting E - expectorating (coughing up) F - funny looking rash (Things to look for)
Describe the pathway for suspected C. Diff infection
Send stool sample (look for CDT)
Take blood samples for WCC, urea, creatinine and albumin
Isolate patient and inform infection control
Stop: antibiotics, PPIs, laxatives, immunosuppressants, opioids
Ensure regular assessment
What features would make a case of C. Diff infection severe?
Sepsis Temp >38.5 Evidence of severe colitis Albumin <25 WBC > 15 Acute rising serum creatinine
What is the treatment for severe C. Diff infections?
Oral vancomycin for 10 days
Needs daily assessment and review
What is the treatment for non-severe C. Diff infection?
Metronidazole (oral) for 10 days
Regular assessment
When can patients who’ve had a C. Diff infection mix with other patients again?
No diarrhoea for at least 48 hours
How are T cells activated?
By antigen presenting cells
What is the difference between intracellular and extracellular microbes?
Replicate inside/outside the host cells
What are the 3 stages that an APC goes through after contact with a pathogen?
Capture
Processing
Presentation
Give some features of APCs
Located in strategic places (where B and T cells are)
Pathogen capture - can use phagocytosis or macropinocytosis
Diversity in pathogen sensors (PRRs)
Where are dendritic cells found?
Lymph nodes
Mucous membranes
Blood
Where are Langerhans’ cells present?
Skin
Which type of APC presents to both T and B cells?
Dendritic cell
Extracellular microbes trigger which immunity first?
Humoral immunity
Antibodies and complement
