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Flashcards in Microbiology Antibiotics 1 Deck (39):
1

Beta Lactams type


1. Penicillins
2. Cephalosporins
3. Carbapenems
4. Monobactams
5. Blactamase inhibitors

2

Penicillin → Discovery

Alexander flemming 1929 used finally in 1940

3

Penicillin → Resistance via

Enzymatic digestion of Beta Lactam ring or target site modification (MRSA) – bacteria change confirmation of enzymes and so B lactams canit bind

4

Penicillin →Absorption

Oral: Poor oral absorption
IV

5

Penicillin →Distribution

Body water about 0.2 L/Kg

6

Penicillin →Metabolism

Peak concentration in 1-2h
Little metabolism

7

Penicillin →Excretion

Mainly urinary excretion

8

Penicillin →Side effects

Generally mild
• Allergy important as is assessment of allergy (analphylactive reactions)
• GI upset especially C.difficile in hospital with broad-spectrum agents.
• Hepatic
• Platelet
• CNS – convulsion
• Platelet abnormalities

9

Penicillin →Indications: Penicillin V/G

B. haemolytic streptococci
Pneumococci
Meningococci
Gonococci (not susceptible anymore)
Anaerobes GPAC and clostridia (gas gangrene)
NB resistance in pneumococci
Gonococci

10

Penicillin →Indications for flucloxacillin

S.aureus (NB resistance MRSA)

11

Penicillin → Indiciation sfor Ampicillin/amoxicillin + clavunate (inhibitor)

Otitis media
COPD exacerbation
CAP
UTI
Skin and soft tissue infection
Surgical prophylaxis
Intra abdominal surgery

12

Penicillin → Piperacillin/tazobactam

Hospital IV therapy 2nd line

13

Penicillin →Broad spectrum example

Ampicillin/amoxicillin

14

Penicillin →Blactam/Blactamase inhiitors example

Co-amoxiclav (amoxicillin-clavulante)
Piperacillin – tazobactam

15

Penicillin →Inhibitor action

Prevent Beta lactamase action so by introducing an inhibitor it can block the enzyme produced y the bacteria aimed to breakdown the antibiotic and so this allows the antibiotic to act.

16

Carbapenems: Example

Meropenem

17

Carbapenems: Specification

Very broad spectrum

18

Carbapenems: Absorption

Injectable only
Used as 2nd/3rd line therapy in hospital

19

Carbapenems:Action

Typical Blactam pharmacokinetics

20

Carbapenems:Resistance

Remains rare

21

Carbapenems:Not active against

MRSA
Stenotrophomonas
Maltophilia
Some enterococci

22

Cephalosporins: Isolated from

Fungus cephalosporium acremonium in Sardinia

23

Cephalosporins: Classified based on

Generations on chronology and antimicrobial spectrum.

24

Cephalosporins:First generation example

Cephalexin

25

Cephalosporins: Second generation example

Cefuroxime

26

Cephalosporins: Third generation example

Cefotaime, ceftriaxone, ceftazidime

27

Cephalosporins: Fourth generation example

Cefpirome

28

Cephalosporins:Bacterial always resistant are:

• MRSA
• Enterococci
• Listeria
• Legionella – no cell wall therefore beta lactams don’t work therefor combine with macrolides
• C. difficile
• Campylobacter
• ESBL producing E.coli, Klebsiella

29

Cephalosporins: Indiciations

• Acute meningitis (cefotaxime/ceftriaxone)
• Surgical prophylaxis (abdominal, orthopaedic, head and neck, obstetrical)
• UTI/acute pyelonephritis
• Chest infection
• CA sepsis of unknown site: ceftriazxone
• Hospital acquired sepsos unknow site: ceftazidine + 2nd agent
• Skin/soft tissue infection
• Intra abdominal infection + metronidazole

30

First generation: Cephalosporins: Active against

Gram positive cocci (Streptococci and Staphylococci) and Gram negatives

31

First generation: Cephalosporins: Used for

UTI (E.coli, Klebsiella, Proteus spp)

32

First generation: Cephalosporins: Absorption

Oral

33

First generation: Cephalosporins: Commonly used in

GP

34

Second generation: Cephalosporins: Active against

Gram positive cocci (Streptococci and Staphylococci)
Gram negatives which cause CAP and exacerbation COPD (H. influenza, M. catarrhalis)

35

Second generation: Cephalosporins: Absorption

Mainly IV

36

Third Generation: Cephalosporins: Active against

Hospital gram negative rods
Poor against gram positive
• Citrobacter
• Serratia for ceftriaxone/cefotaxime
• Pseudomonas aeruginosa for ceftazidime

37

Third Generation:Cephalosporins: Absorption

Mainly IV

38

Fourth Generation: Cephalosporins: active for

Similar spectrum to ceftazidime but also good activity against some gram positive cocci.

39

Blactamase inhibitors: exampe

Co-amoxiclav (amoxicillin and clavulanic acid)

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