Flashcards in I&I Deck (92)
What is microbioata?
-Normal commensal bacteria carried on skin and mucous membranes which are harmless or even beneficial.
What are the 4 ps of prevention? Describe how each category works
-Patient -> anything that the patient can do to minimise infection eg MRSA screen, disinfectant bodywash, stop smoking, keep nutrition good
-Pathogen -> factors which try to overcome prevention -> virulence factors eg toxin production, abx resistance
-Place -> what can be done to the built environment to minimise infection -> easy clean furnishings, single use medical devices, good food hygiene and kitchen facilities
-Practice -> goverment policies and training on infection prevention. hand hygiene, ppe etc
What is the gram status/shape of staphylococcus/streptococcus? How do you differentiate between the two?
-Staphylococcus are often in clusters (grapes)
-Strep pneumonia -> diplococci
What is the gram status/shape of neisseria?
-gram negative diplococci
What is the gramstatus/shape of E.coli, Klebsiella, salmonella and haemophilus?
-Gram negative bacilli
What is the gram status/shape of clostridium?
-Gram positive rods
What are the ideal features of an antibiotic?
-Short time course
-Minimal off target effects
-Easy formulary ie oral with long half life
-Reach site of infection
Which categories of Abx affect cell-wall synthesis? How do they work? Give examples
-B lactams -> penecillin (amoxicillin, cephalosporins (ceftriaxone) Carbapenems (meropenem)
-bind to penecillin binding protein or cell wall cross linking enzyme to prevent cross linking of peptidoglycan
Which catagories of Abx affect protein synthesis? give examples
-Tetracyclines -> doxycycline
-Aminoglycosides -> gentamicin
-Macrolides -> erythromycin
Which catagories of Abx affect nucleic synthesis? How do they work? give examples
-Quinolones -> ciprofloxacin
-Bind to enzymes involved in DNA replication to prevent nucleic acid synthesis/assembly
What are the 3 main mechanisms of resistance in bacteria?
-Drug inactivating enzymes eg b-lactamases
-Altered drug targets so abx has lower affinity eg methicillin resistance
-Altered uptake eg increased efflux or decreased permeability
How do bacteria acquire resistance? Describe each method
-Chromosomal gene mutation -> one bacteria has altered chromosomes -> Abx kills rest of bacteria -> the resistant one multiples
-Horizontal gene transfer -> conjugation between two bacteria passes transposon, transduction by a bacteriophage, transformation by uptake of plasmid
Give two penicillin containing abx which may be misgiven in hospital in a penicillin alergic
-Co-amoxiclav (amoxicillin + clavulanic acid)
-Tazocin (piperacillin + tazobactam)
Which organisms do penicillins target?
-Mainly strep and staph
Which organisms do cephalosporins treat? What special considerations are given to ceftriaxone?
-Broad gram negative spectrum
-Ceftriaxone has good activity in CSF. Also concern over associated infection with c.diff
What target organisms do carbapenems treat? When can this be used in penicillin allergy?
-V broad spectrum of gram negative bacteria inclusing anaerobes
-Generally safe in penicillin allergy other than anaphylaxis
What are the target organisms of vancomycin? When is it given orally?
When are tetracyclines used? When should it not be used and why?
-For gram positives with penicillin allergy
- Children under 12 due to deposition causing yellow staining of bones and teeth
What are the target organisms of gentamicin? When is it used?
-Gram neg sepsis
When is eythromycin used?
-Alternative to mild gram pos infection in penicillin allergic
When is trimethoprim used and what is an alternative? How does it work?
-Inhibits bacterial DHFR preventing folic acid synthesis necessary for dna synthesis
Describe the treatments of candida
-Nystatin for oral
What is aciclovir and when is it used?
-Antiviral which inhibits DNA polymerase
-Herpes simplex, varicella zoster
What is oseltamivir? How does it work?
-Inhibits viral neuroamidase
What is metronidazole and when is it used?
-Antibacterial and antiprotozoal
-Anaerobic bacteria, amoebae, giardia and trichomonas
How is neisseria meningitidis spread? State 3 virulence factors. What are the life threatening complications of meningitis? What is the treatment for meningitis?
-LPS endotoxin, pili and polysaccharide capsule
-Supportive + ceftriaxone
When would you suspect sepsis in a patient?
-Temp <36 or >38
-WBC<4 or >12
with history of infectious source/presumed reason for infection
-Organ dysfunctioneg low bp, low urine output
What is the sepsis 6?
-high flow o2
List some first line physiological barriers if the innate immune system