Antibiotics Flashcards
Infection types; Structural features of bacteria, Guidance for abx use; Types of bacteria; Mechanisms of abx; 5 Classes of abx; Abx resistance; Viruses; Monitoring infections
What are the names of the two areas where health acquired infection can occur?
Community and healthcare
4 types of infection
by what
Bateria
Fungal
Viral
Parasitic
9 general full body symptoms of infection
Pyrexia Headache Sore throat Abdominal pain Lethargy Joint/muscle pain Nausea / vomiting Diarrhoea Rash
4 key structural features of bacteria
No nucleus
2x forms of DNA
Peptidoglycan cell wall
Ribosomal subunit different to that in eukaryotes (mammalian cells)
Names and functions of the 2 forms of DNA in bacteria
Plasmid DNA - allows for self replication
Nucleoid - chromosomes, protein synthesis, RNA molecules
What is the generic name for the treatment of parasitic infections?
Anti-protozoal
Names of the 2 types of bacteria
staining
Gram positive
Gram negative
What structural feature is it of gram negative bacteria that make them difficult to treat with abx?
Protective outer membrane
What ideally is the first action that should be carried out before abx administration?
Bacteria cultures and sensitivities sent to the lab
What 4 investigations/tests are used to guide abx use?
Blood tests
Urine samples
Swabs
Stool samples
What 3 blood tests and results (i.e.higher/lower) would indicate infection?
White cell count - >11= bacterial infection, <5 = viral infection
Neutrophils - increased during bacterial infection
C-Reactive Protein - increased during infection/injury
What do bactericidal antibiotics do and name 3 examples?
Kill bacteria.
Penacillin, cephalosporins, quinolones
What do bacteriostatic antibiotics do and name 2 examples?
Inhibit bacterial growth.
Tetracyclines, macrolides
What is the intention of bacteriostatic abx therapy? What may it detrimentally result in in terms of stopping infection?
Intends to suppress bacterial division so that body’s own immune system is able to eradicate infection.
Detrimentally, it is the reason infections may continue to occur despite abx treatment.
Name 5 mechanisms of which abx ihibit bacteria
Peptidoglycan synthesis - cell wall Cell metabolism DNA/RNA metabolism Degrade plasma membrane Protein synthesis
What two mechanisms of abx mean they will only effect bacteria and why?
Peptidoglycan synthesis - because human cells have no cell wall
Protein synthesis - because bacteria have a different subunit to that of human ribosomes
Name 5 classes of abx
Beta-lactams Macrolides Cephalosporins Penacillins Tetracyclines
What is a key structural feature of beta-lactam abx and how may bacteria become resistant to them?
All abx with a beta-lactam ring
Bacteria may develop to synthesise beta-lactamase which hydrolyses the beta-lactam ring leaving abx ineffective and bacteria resistant.
What might be included in abx to combat bacteria producing beta-lactamase to make them effective?
Beta-lactamase inhibitors
Mechanism for how penicillin works?
bacteriostatic/cidal, inhibit what
Bactericidal
Inhibit peptidoglycan synthesis and DNA/RNA metabolism - preventing bacterial growth/division
What spectrum of abx is penicillin and what gram of bacteria does it work on?
Broad spectrum
Works on gram -ve and +ve bacteria
5 ADRs of penicillin
Rash Nausea/vomiting Pyrexia Diarrhoea GIT disturbance
2 ADRs of penicillin given IV
Increase in sodium
Convulsions
Mechanism for how cephalosporins work?
bacteriostatic/cidal, inhibit what
Bactericidal
Inhibit peptidoglycan synthesis
What spectrum of abx are cephalosporins and what generation is most effective on which gram of bacteria?
Broad spectrum
Old generation most effective on gram -ve
New generation most effective on gram +ve
4 ADRs of cephalosporins
GIT disturbance
Caution in pts with penicillin allergy
Rash
Pyrexia
Which abx (of the other 4) contain a beta-lactam ring?
Penicillin
Cephalosporins
Mechanism for how macrolides work?
bacteriostatic/cidal, inhibit what
Bacteriostatic and bactericidal
Inhibit protein synthesis via irreversibly binding to ribosomal subunit, preventing replication or repair.
What spectrum of abx are macrolides and what gram of bacteria are they most effective on?
Narrow spectrum
Works on gram +ve bacteria
2 ADRs of macrolides
Liver damage
GIT disturbance
Interaction of macrolides and resulting effect
CYP
CYP450 inhibitors - reduce drug metabolism leading to drug accumulation
Mechanism for how tetracyclines work?
bacteriostatic/cidal, inhibit what
Bacteriostatic
Inhibit protein synthesis by binding irreversibly to ribosomal subunit preventing mRNA synthesis
What spectrum of abx are tetracyclines and what gram of bacteria are they most effective on?
Broad spectrum
Work on gram -ve and +ve bacteria
3 ADRs of tetracyclines
GIT disturbance
Photosensitivity
AVOID use in children as slows bone growth and alters colour of teeth
What interacts with tetracyclines to form an insoluble compound?
Milk
Name the two types of bacterial resistance
Natural innate resistance
Acquired resistance
How does innate bacterial resistance develop?
Over time to the environment bacteria lives within
How does acquired bacterial resistance develop?
Bacteria sharing their resistance between one another
3 ways innate ways bacterial are resistant to abx
Impenetrable peptidoglycan wall/cell membrane
No receptor on bacteria for abx to bind to
Abx susceptible to enzymes produced by bacteria
2 ways in which acquired antibiotic resistance occurs
Production of enzymes that inactivate abx
Changes to abx structure preventing binding of abx
6 ways in which bacteria become resistant to abx
Selection of resistant bacteria Mutated to be resistance Transferred resistance Production of abx inactivating enzymes Impermeability of cell wall/membrane Altered structure abx unable to bind
What ADR is seen in all abx?
GIT disturbance
3 steps in the prescribing of abx
Send cultures and sensitivities before commencing abx.
Indication and duration of abx use.
Review need, dose or type of abx in 48hrs
What are viruses and two features?
Intracellular parasites, have no metabolism, require host to replicate
6 steps of monitoring/assessing infection
Obtain symptom onset /pt history White cell count Temperature CRP Erythrocyte sedimentation rate Exposure to infection Cultures
