Topic 1-General considerations of antimicrobial therapy. Disinfectants and antiseptics

Question 1

Examples of bactericidal agents

Answer 1

-beta lactams -glycopeptides -aminoglycosides -fluoroquinolones

Question 2

Examples of bacteriostatic abx

Answer 2

-choramphenical -macrolides -tetracyclines

Question 3

Three types of abx therapy

Answer 3

-empiric-no time to identify microorganism responsible for the infection -sensitivity-make antibiogram to know which abx they are sensitive to -prophylactic

Question 4

Effective therapy depends on which characteristics of the drug

Answer 4

1.)pathogen has to be sensitive to abx 2.)antimicrobial has to be in effective concentration at site of infection -pharmacokinetics of the drugs -route of administration -dose -adverse effects

Question 5

What is post antibiotic effect

Answer 5

The period of time when the bacteria doesn’t continue it’s growth after levels of abx has fallen below MIC (This means that abx with long PAE like fluoroquinolones only require one dose per day)

Question 6

What is MIC and MBC

Answer 6

The lowest antimicrobial concentration that prevents visible growth of an organism after 24 hours. MBC is minimum of bactericidal concentration

Question 7

3 types of MBC ABX types

Answer 7

1.) Concentration dependent abx activity -aminoglycosides and daptomycin -once a day infusion achieves high peak levels, favoring rapid killing of the infecting pathogens (not always done) 2.)Time-dependent antibacterial activity -beta lactams -multiple dosing or continuous infusion to prolong MIC 3.)AUC/MIC -Fluoroquinolones -concentration dependent ABX, but resistant mutants are formed, high concentration maintained maintained for long time to be effective

Question 8

Time-dependent antibacterial activity? (Example)

Answer 8

How long will effective ABX present at site of infection

Question 9

3 reasons to have combination therapy?

Answer 9

1.) Synergistic effect 2.)To extend the antibacterial spectrum 3.)To prevent the development of resistance

Question 10

Indications of prophylactic treatment (2 reasons and explanation)

Answer 10

1.) Surgical prophylaxis-Decreases incidence of potential infection after procedure (dental or heart valve procedure) 2.) Non-surgical prophylaxis- Individuals with high risk (immunocomprised) Recurrent infections Close contact (meningococcal) Risk of infection (malaria, anthrax)

Question 11

3 antibacterial spectrum types and a example

Answer 11

1.) Narrow spectrum -Gram +/aerobic/anaerobic (vancomycin) 2.) Extended spectrum? 3.) Broad spectrum -Gram +/-/aerobic/anaerobic (carbapenems)

Question 12

What do you have to take in account for dosing?

Answer 12

1.) Newborns vs Elderly have different means of elimination 2.) Weight (aminoglycosides don’t enter fat so it’s not a proportional increase with weight 3.) Increased extracellular space (ascites, newborns, pregnant) so a higher does is needed

Question 13

During of treatment typically? UTI? Pneumonia? Chronic treatment/difficult to reach site (chronic prostitis)? Osteomyelitis? Tuberculosis?

Answer 13

Typically 5 days UTI is 5 day treatment pneumonia is 7-10 days chronic treatment is 3-6 weeks osteomyelitis is 4-6 months tuberculosis is half a year

Question 14

Main compications of ABX therapy ( 4 answers)

Answer 14

1.) hypersensitivity 2.) direct toxicity (aminoglycosides cause ototoxicity and nephrotoxicity) 3.)super-infections 4.) High concentration of penicillin cause seizures

Question 15

3 Antibiotics that are safe in pregnancy?

Answer 15

beta lactams, macrolides, and cephalosporins

Question 16

Which antibiotics can go intracellularly? How?

Answer 16

Macrolides, fluroquinolones, or tetracyclines can be uptaken by active transport

Question 17

Types of antibiotic mechanism

Answer 17

1.) cell wall synthesis inhibitors 2.)protein inhibitors 3.) DNA damagers

Question 18

How do bacteria form resistance (4 methods)

Answer 18

1.) Bacteria creates enzyme to break down abx Such as beta lactamases, sensitivity varies Most sensitivity=penicillin Moderate sensitivity=cephalosporin Least sensitive=carbapenems 2.)Changing of PBP binding site MRSA This is not the case in 5th generation cephalosporins 3.)Decreased permeability Gram - change number of pores or absence of pores 4.)Efflux pump