Overview of Infections and Antibiotics Flashcards
What chapter of BNF does it cover
5
antimicrobials and antibiotics
antimicrobials is more broad > can be antivirals for example
Pathogenic bacteria
stain - +ive or -Ive
oxygen - anaerobes
shapes - coccus…
infection markers?
systemic
peripheral/ local
vital signs
haematology
Biochemistry
Microbiology tests that can be used to confirm a source of infection
Urinalysis
Systemic
fever, rigor, chills myalgia, malaise, headache, anorexia, delirium
peripheral/ local
erythema, pain, heat, swelling, pus
vital signs
change in body temp, tachycardia, hypotension, tachypnoea
Haematology
^ white blood cell count
changes in neutrophils, ^ but low in neutropenic
^ platelets
Biochemistry
^ C reactive protein
^ erythrocute sedimentation rate
^ serum creatinine
^ liver func. test
changes to procalcitonin level
Microbiology tests that can be used to confirm a source of infection
presence of organism
miscroscopy
culture
serology
polymerase chain reaction
urinalysis
presence of leucocyte esterase
presence of nitrates
Which bacteria causes whcih infections?
- most: natural body flora
Tets; CAP
community acquired pneumonia
Flora in the nasal cavity and the nasopharynx incl. mixtures of Gram -ve and gram +ve anaerobes
exceptions : clostridium difficle
gram +ve anaerobe
minor part of normal gut flora
risk factors:
exposure to broad spec antibiotics
multiple antibiotic exposures
proton pump inhibitor use (PPI)
co-morbidities
Pseudomonas Aeruginosa
gram -ve bacillus
not part of naturla flora
able to live in various enviroments
oppurtunistic pathogen
immunocompromised hosts are susceptible
what is an aim of antibiotic?
- trial to kill bacteria - not healthy cells
- target physiology or biochemistry; bind to target, occupy enough of binding site, remain at binding site for sufficient time period
dose optimisation graph
t = time
MIC = minimum inhibitor concentration
What are the 4 types of antibiotics
- narrow spectrum
- broad spectrum
- bactericidal
- bacteriostatic
different mechanisms of resistance
- penetration resistance
- efflux pump
- hydrolysis
- mutation of binding site
Principles of therapy
- antibacterial drug choice
- antibacterials, before therapy
- advice to give to patients/ family/ carers
- antibacterials, during therapy
- superinfection
- notifiable diseases
- sepsis and early management (if yes, treat 1 hr)
Choice of antibiotic:
- patient factors
- likely causative organism
- risk of bacterial resistance
- pateint factors when choosing an antibiotics
history of allergy
ranal/hepatic function
susceptibility to infection
ability to tolerate drugs by mouth
severity of illness
risk of complications
ethnic origin
age
female?
previous antibiotics
previous microbiology results
- likely causative organism
site
likely pathogen
antibacterial activity
What if patient has treatment failure:
repeated antibacterial courses
previous or current culture with resistant bacteria
higher risk of developing complications
viral infections considerations before starting therapy?
viral infections
samples should be taken for culture
knowledge of prevalent organisms
dose
route of administration
duration
review antibacterials - what to do?
review chocie of antibacterial
absense of culture, review and stop on clinical grounds
review Iv antibacterial within 48 hrs
consider stepping down to oral antibacterials where possible
Penicillin side effects
hypersensitiviy, diarrhoea, antibiotic associated colitis, encephalopathy, thrombocytoenia
cephalosporins - generations
1st:
cefalexin
cefradine
cefadroxil
2nd cefaclor
cefuroxime
3rd:
cefixime - orally active
ceftiaxone
cefotaxime
ceftazidine
5th:
ceftaroline
Cephalosporins - considerations
cross sensitivity with other beta-lactam antibacterials
no suitable alternative is avail; cefixime can be used in caution
side effects of cephalosporins
antibiotic - associated colitis
aminoglycosides - drug examples
amikacin, gentamicin, neomycin, streptomycin, tobramycin
Gentamicin serium concentrations
- 1 hr peak conc
5-10mg/L
pre-dose trough concentration
<2mg/L
cautions & contraindications
auditory disorders
nephrotoxicity
muscular weakness
dehydration corrected prior to administration
side effecst of aminoglycosies
irreversible otoxiticy, nphrotoxicity, antibiotic - associated colities, peripheral neuropathy
MHRA/CHM advice ^ risk fo deafness in patients with mitochondrial mutations
Glycopeptides
vacomycin, teicoplanin, telavacin
cautions & contraindications:
avoid history of deafness, elderly caution, patienst with inflammatory disorder
monitor - trough level 10-20mg/L
interactions
avoid otoxic drugs, loop diuretics
Macrolides
azithromycin - OD
Clarithromycin - BD
erythromycin - BD/QDS
s.e Gi, rash, otoxicity
clarythromycin; take with or just after food
cautions and contraindications of macrolides
interaction between drugs?
patients with predisposition of Ot interval, prolongation
interaction between rivaroxoban and erythromycin
= ^ risk of bleeding
Quinolones
ciprofolaxacin, levofloxacin, moxifoxacin, norfloxacin, olfoaxin
s.e prolongs OT iontervals, seizires, GI s.e, dizziness, headache, eye disorders, dec. in appetite
avoid in pregnancy
Tetracyclines
s.e diarrhoea, dysphagie, photosensitivity
cautions - headache and virual disturbances
dont give to pregnant women - going to go through placenta
do not give to children udner 12 - stain teeth and growing bones
hypertension? STOP drug
trimethoprim
cautions - blood dyscrasias
s.e allergic reactions, drug fever, electrolyte imbalance, GI disturbances, fungal overgrowth
monitor
hyperkalaemia, ^ creatine conc, renal funcion
interactions?
not used wiuth potassium evelating drugs (aldosterone atagonist, ACEi, ARBs)
not used with folate antagonists, or durgs that increase folare metabolism (phenytoin)
`nitrofurantoin
s.e
pulmonary reactions, nausea, hypersensitivity, peripheral neuropathy, blood disorders
minor -
renal func.
avoid if eGFT <45ml/min
long term - monitor liver function
cautionsanaemia, diabetes, elec. oimbalance
pregancy, avoid
taken with or just after food, may discolour urine
Clindamycin
cautions - shoudl not be used if existing diarrhoea
s.e - antibiotic- associated colitis, GI s.e, taste disturbances, rash, steven johnson syndrome, skin
monitor liver and renal func if treatment exceeds 10 days
counelling
patients should be advised to discontinue if diorrhoea develops
cream - can damage latex condoms
Metronidazole
s.e Gi se, taste disturbances, furred tongue, oral mucosits, anorexia
do not drink alochol - cause stroke like symptoms
cautions - 10 days vaginal
topical use 18 yrs - avoid sunlight
