gram positive organisms Flashcards
(48 cards)
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Take history of relevant allergies
Initiate prompt effective antibiotic treatment within 1 hour of diagnosis (or as soon as possible) in patients with life- threatening infections
Comply with local prescribing guidance
Document clinical indication and dose on
drug chart and in clinical notes
Include review / stop date or duration- all bloods back by 48 hours
Ensure relevant microbiological specimens taken
clinical review at 48 hours:
clinical review, check microbiology, make and document decision:
- STOP
- IV/oral switch
- change to arrow spectrum
- continue and review again after a further 24 hours
- OPAT
gram positive bacteria can be
cocci or bacilli
gram positive cocci can be further divided into?
staphylococci, streptococci, enterococci
gram positive bacilli can be further divided into?
listeria monocytogenes
clostridia
corynebacterium
what is more common cocci or bacilli?
cocci
common staphylococci
Staph, aureus (MSSA and MRSA)
staph. epidermidis and other coagulase neg staphylococci
common enterocci
E. faecalis and E. Faecium
VRE
common clostridia
clostridioides difficile
clostridium perfringens
common corneybacterium
aka diphtheroids
not the same as diphtheria
B Lactams
Arguably most important drug class
• Multiple modifications over time have increased spectrum of
activity
• Allergy is due to a degradation product of the beta lactams
• True beta lactam anaphylaxis is <0.05 %
what are B lactam antibiotics?
- Penicillin
- Flucloxacillin
- Amoxicillin
- Cephalosporins
- Piperacillin/tazobactam
- carbepenems
true anaphylaxis with penicillins is
in less than 5% of cases
what causes the allergy in penicillins?
Beta-lactam ring
what is bioavailability?
- Mild infections are often treated in the outpatients , orally
- Some drugs taken orally are almost completely absorbed and achieve high levels in the serum
- Sepsis usually requires intravenous antibiotics
over time, depending on the route of the drug, will determine the amount of drug remaining in the blood
what is minimum inhibitory concentration?
how much drug you need to kill the pathogen
concentration of drug required for kill of 99.9% of organisms during 18 to 24 hours
• the concentration of drug that allows a tube (or well) containing the pathogen to remain clear by visual examination after 18 to 24 hours.
• Useful for guiding endocarditis, meningitis antimicrobial choi
general roles?
• More difficult for antibiotics to get into areas with tight junctions • Central nervous system, eyes, prostate
• Antibiotic penetration usually be site dependant
• Within the same class of antibiotic, agaents may have a different
spectrum and site penetration
• Biofilms require special thought ( CF, bronchiectasis, prosthetic material)
gram positive streptococci shape
pairs or chains
gram positive streptococci features
Gram positive cocci occur in pairs or chains
• Catalase positive , need particular nutrients
• Nutritionally fastidious, require complex media, preferably supplemented with blood
• ‘Facultative anaerobes’
what are facultative anaerobes?
‘Facultative anaerobes’ (grow aerobically and anaerobically – technically though they do not use oxygen in metabolism, some are capnophilic, some prefer anaerobic conditions for growth
beta hemolytic strep
complete lysis next to growth
clear zone
alpha hemolytic streptococci
partial hemolysis
greenish color to the blood agar
hamma haemolytic streptococci
non-haemolytic
lance field antigen
20 antigens in cell wall • Differences in carbohydrate • A to U ( without the letter I or J) • Not useful for all streptococci • Usefulness of classification changed with pcr and other molecular methods • Nomenclature remains
