Microbiology Antibiotics 1

Question 1

Beta Lactams type

Answer 1

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

Question 2

Penicillin → Discovery

Answer 2

Alexander flemming 1929 used finally in 1940

Question 3

Penicillin → Resistance via

Answer 3

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

Question 4

Penicillin →Absorption

Answer 4

Oral: Poor oral absorption

IV

Question 5

Penicillin →Distribution

Answer 5

Body water about 0.2 L/Kg

Question 6

Penicillin →Metabolism

Answer 6

Peak concentration in 1-2h

Little metabolism

Question 7

Penicillin →Excretion

Answer 7

Mainly urinary excretion

Question 8

Penicillin →Side effects

Answer 8

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

Question 9

Penicillin →Indications: Penicillin V/G

Answer 9

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

Question 10

Penicillin →Indications for flucloxacillin

Answer 10

S.aureus (NB resistance MRSA)

Question 11

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

Answer 11

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

Question 12

Penicillin → Piperacillin/tazobactam

Answer 12

Hospital IV therapy 2nd line

Question 13

Penicillin →Broad spectrum example

Answer 13

Ampicillin/amoxicillin

Question 14

Penicillin →Blactam/Blactamase inhiitors example

Answer 14

Co-amoxiclav (amoxicillin-clavulante)

Piperacillin – tazobactam

Question 15

Penicillin →Inhibitor action

Answer 15

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.

Question 16

Carbapenems: Example

Answer 16

Meropenem

Question 17

Carbapenems: Specification

Answer 17

Very broad spectrum

Question 18

Carbapenems: Absorption

Answer 18

Injectable only

Used as 2nd/3rd line therapy in hospital

Question 19

Carbapenems:Action

Answer 19

Typical Blactam pharmacokinetics

Question 20

Carbapenems:Resistance

Answer 20

Remains rare

Question 21

Carbapenems:Not active against

Answer 21

MRSA
Stenotrophomonas
Maltophilia
Some enterococci

Question 22

Cephalosporins: Isolated from

Answer 22

Fungus cephalosporium acremonium in Sardinia

Question 23

Cephalosporins: Classified based on

Answer 23

Generations on chronology and antimicrobial spectrum.

Question 24

Cephalosporins:First generation example

Answer 24

Cephalexin

Question 25

Cephalosporins: Second generation example

Answer 25

Cefuroxime

Question 26

Cephalosporins: Third generation example

Answer 26

Cefotaime, ceftriaxone, ceftazidime

Question 27

Cephalosporins: Fourth generation example

Answer 27

Cefpirome

Question 28

Cephalosporins:Bacterial always resistant are:

Answer 28

* 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

Question 29

Cephalosporins: Indiciations

Answer 29

* 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

Question 30

First generation: Cephalosporins: Active against

Answer 30

Gram positive cocci (Streptococci and Staphylococci) and Gram negatives

Question 31

First generation: Cephalosporins: Used for

Answer 31

UTI (E.coli, Klebsiella, Proteus spp)

Question 32

First generation: Cephalosporins: Absorption

Answer 32

Oral

Question 33

First generation: Cephalosporins: Commonly used in

Answer 33

GP

Question 34

Second generation: Cephalosporins: Active against

Answer 34

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

Question 35

Second generation: Cephalosporins: Absorption

Answer 35

Mainly IV

Question 36

Third Generation: Cephalosporins: Active against

Answer 36

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

Question 37

Third Generation:Cephalosporins: Absorption

Answer 37

Mainly IV

Question 38

Fourth Generation: Cephalosporins: active for

Answer 38

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

Question 39

Blactamase inhibitors: exampe

Answer 39

Co-amoxiclav (amoxicillin and clavulanic acid)