Healthcare associated infections Flashcards
What is an infection?
deposition and multiplication of bacteria and other micro-organsisms in tissue or on surfaces of the body with an associated tissue reaction
When does colonisation occur?
if the response of the host is slight or absent
What are the different sources of infection?
endogenous = caused by hosts own resident organisms
exogenous = caused by organisms foreign to the host
What are the different modes of transmission of an infection?
airborne faecal -oral contact blood borne injection / inoculation sexual
What are some examples of host vulnerability?
extremes of ages immunocompromised drug therapy invasive devices pregnancy underlying disease nutritional state trauma
What are some local signs of infection?
erythema swelling pain oedema purulent discharge heat
What are systemic signs of infection?
sepsis
- fever or hypothermia
- rigor
- hypotension
- tachycardia
- raised WCC and CRP
- increased serum lactate
What are healthcare associated infections?
any infection acquires as a result of accessing healthcare
- could include acute hospital, rehabilitation facility, nursing or residential home
How common are healthcare associated infections?
at any one time 10% of patients will have them
risks vary according to the kind of setting e.g. ICU, type of patient
costs the NHS £1 billion
What are some different types of infections?
pneumonia urinary infection surgical site infection gastroenteritis bloodstream infection
Are HCAI preventable?
studies suggest 15% are preventable
predominantly exogenous
predominantly device associated
Why are HCAI a particular problem now?
vulnerable patients:
- extremes of life
- complex high tech treatments
use of antibiotics
- resistance means we are starting to run out
What does the health and social act of 2008 state?
all NHS trusts must register with care quality commission
- meet legal requirements, NHS trusts must ensure that patients, workers and others are protected agains the identifiable risks of acquiring an HCAI
CQC conduct unannounced inspections
What are the major current organisms of concern?
MRSA c diff MDR acinetobacter vancomycin resistant enterococci multiply resistance enterobacteriaceae pseudomonas aeruginosa from water sources mycobacterium tb
What is MRSA?
Meticillin resistant staphylococcus aureus
- common bacteria carriedby approx 30% pop
- resistant to flucloxacillin
- causes range of infections - some trivial, some serious
- often colonises without causing infection
What can MRSA cause?
skin infections chest infections endocarditis bone infection bacteraemia death
Why does MRSA cause an infection?
about 30% of people carry MRSA
Cross infection in community and hospitals
antibiotic misuse
patients not screened
What can be done to prevent MRSA infections occurring?
nasal swab
groin swab
wounds, urine, line sites, sputum
investigations of acquisitions to extract learning
targets set locally on number of blood stream infections
What is C. diff?
anaerobic gram +ve bacilli lives in the gut produces spores resists drying resists abx produces toxins toxins produce diarrhoea
What does C.diff cause?
watery diarrhoea abdominal pain pseudomembranous colitis dehydration bowel perforation death
Why is C. diff important?
human costs:
- morbidity and mortality
- 16/17 12840 cases
- costs healthcare an estimated £4500-9000
Why does C. diff occur?
antimicrobials prescribed for infection
colonisation due to cross infection
overgrowth of the bacteria in the gut
toxin causes bowel damage
What is the protocol for patients with C.diff?
1) stop abx if possible
2) start treatment
3) monitor fluids
4) specialist review
5) terminal clean when better
6) ensure discharge info given
What are the treatments for c.diff?
mainly focussed on drugs which kill c. diff
- metronidazole
- oral vancomycin
- fidaxomicin
What is a new treatment for c.diff?
donor faecal transplant
What is enterobacteriaceae?
large fam of bacteria
live harmlessly in the bowel of healthy individuals
can be pathogens and cause disease
What bacteria are part of the enterobacteriaceae family?
common bacteria isolated in a healthcare setting:
- e.coli
- klebsiella
- enterobacter
- proteus
- salmonella
- serratia
- citrobacter
What infections can be caused by enterobacteriaceae?
wide range of infections:
- UTI (70-90%)
- intraabdominal infections
- pneumonia
- bacterial meningitis
- septic arthritis
- osteomyelitis
- endocarditis
- bacteraemia
How was penicillin discovered?
it was noted that it inhibits the growth of staphylococcus
What are carbapenems used for?
meropenem, ertapenem, imipenem, doripenem
often used as a last resort for treating infections caused by antibodies resistant enterobacteriaceae
What are carbapenemases?
enzymes produced by bacteria that destroy carbapenem abx
made by small but growing number of enterobacteriaceae strains
What are the different type carbapenemases?
KPC, OXA-48, NDM, VIM enzymes
What are examples of carbapenem producing organisms?
acinetobacter baumannii
pseudomonas aeruginosa
stenotrophomonas maltophilia
What are carbapenem producing enterobacteriaceae?
klebsiella pneumoniae
escherichia coli
enterobacter cloacae
What is colistin resistance in china?
emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and humans in china
- highest users of colistin in agriculture
What are the principles for controlling multi drug resistant gram negative bacteria?
screening - complex need to screen stool/rectal swabs, culture versus molecular isolation hand hygiene decontamination of the environment antibiotic restriction
What does CPE stand for?
carbapenemase-producing Enterobacteriaceae
What is acinetobacter baumannii?
gram negative bacillus
multi-drug resistant
- colistin and tigecycline as reserve agents
- moving towards pan -resistance
adapted to hospital environment
- forms biofilms on equipment and wounds
- able to withstand desiccation
associated with
- wound colonisation and ventilator associated pneumonia
- returning military personnel from iraq and afghanistan
Why is the value of screening for MDR acinetobacter controversial?
environmental screening can be useful to detect persistent environmental contamination
cleaning and decontamination - some evidence for hydrogen peroxide vapour
What cleaning control measures are there for MDR acinetobacter?
environmental screening
enhanced cleaning
decant and deep clean
use of hydrogen peroxide
implement rapid cleaning team
commence inter-theatre trip terminal cleaning
embed an assurance framework for cleaning theatres
What is pseudomonas aeruginosa?
widespread in the environment - soil, water, moist environment
- usually colonises hosp and domestic sink taps, traps and drains
- humans may be colonised at moist sites
- highly opportunistic pathogen
- outbreaks in burns are freq reported from water sources
- water transmission has become a matter of urgent concern
