Healthcare Acquired Infection, Infection Prevention and Infections on Surfaces

Question 1

• give some examples of healthcare acquired infection pathogens
• give some factors of the patient that may increase their risk
• what are the 4 Ps of prevention and control?

Answer 1

• blood borne eg hepB, C, HIV , influenza, staph aureus (incl MRSA), clostridium difficile, escherichia coli, Candida albicans, malaria
• very old or very young, diabetes, obesity or malnourished, cancer, immunosuppressed, smoker
• 1=Patient, general and specific risk factors for infection, interactions w other patients, staff etc. 2=Pathogen, virulence factor ps, ecological interactions w other bacteria. 3=Practice, policies, implementation, general and specific actions of staff. 4=Place, healthcare environment

Question 2

• give some general and specific patient interventions to help reduce their risk of infection
• what are the 5 Is for patients with a suspected infection?

Answer 2

• general= optimise the patients condition, stop smoking and drinking etc, skin preparation, hand hygiene, specific=MRSA screens, disinfectant body washes, physical barriers between patients
• 1)identify=gone abroad?bloodborne, colonised, diarrhoea/vomiting, funny rash, 2)isolate 3)investigate 4)inform 5)initiate treatment

Question 3

• give the consequences of transmission, defining each.
• what is the R number?
• what interventions are there concerning the pathogen/ vector?

Answer 3

-endemic= usual background rate
Outbreak=2 or more cases linked in time and place
Epidemic=rate of infection higher than the background rate
Pandemic=very high rate of infection spreading across many regions, countries
-R number = average number of cases 1 case will generate in a non immune pop, if under 1 cases are decreasing, if over 1 they’re increasing
-reduce or eradicate the pathogen/ vector eg antibacterials, decontamination, eliminate vector breeding sites

Question 4

• what are patient interventions to eliminate infection?
• what is herd immunity?
• give some good and bad consequences of control.

Answer 4

• improve health via nutrition and medical treatment, immunity ie passive via mother or active via vaccine
• herd immunity= when enough people are immune eg via vaccination it offers protection to those who are not and reduces transmission rate.
• good=decreased incidence or elimination eg smallpox, nearly polio. Bad=decreased exposure to pathogen-> decreased immune stimulus, fewer antibodies so increased susceptibility and an outbreak of increased severity.

Question 5

• what is a surface?
• give examples of skin microorganisms.
• how can microbiota/commensals cause infections?
• how can microbiota spread?

Answer 5

• an interface between a solid and either a liquid OR gas
• viruses (herpes simplex), bacteria gram pos(staph aureus), gram neg(enterobacteria), fungi (yeasts) parasites (mites)
• normally harmless on surface of skin but if disturbed or transferred to other sites it can be harmful.
• invasion, migration, inoculation

Question 6

• give internal and external examples of natural surface infections.
• give examples of prosthetic surface infections.
• give the processes in the pathogenesis of infection at surfaces.

Answer 6

• external=cellulitis, conjunctivitis, UTIs, internal=endocarditis, septic arthritis, osteomyelitis
• IV lines, prosthetic joints, cardiac valves
• adherence to host cells or surface, biofilm formation (like a slime layer w ecm and nutrients), invasion and multiplication, host response

Question 7

• what is quorum sensing?

- how do you manage the infection? Include diagnosis and treatment.

Answer 7

• the ability to detect and respond to cell population density by gene regulation. (By bacteria)
• diagnosis to identify the microorganism, difficult when there a small colony, use blood cultures or tissue biopsy, to treat=sterilise tissue to reduce bioburden, surgery to resect infected material if needed, antibacterials.