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Flashcards in I&I Deck (92)
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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?

-Positive cocci
-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?

-Highly selective
-Minimal DDIs
-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)
-Glycopeptides (vancomycin)
-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?

-Gram positive


When are tetracyclines used? When should it not be used and why?

-For gram positives with penicillin allergy
-Atypical pneumonia
- 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 negatives
-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?

-Resp secretions
-LPS endotoxin, pili and polysaccharide capsule
-Raised ICP
-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?

-Blood culture
-Urine output
-IV fluids
-Empirical abx
-serum lactate
-high flow o2


List some first line physiological barriers if the innate immune system



List some characteristics of the innate immune system

-Non-changing between infections