Anti bacterial drugs

Question 1

What is an antibiotic

Answer 1

Synthetic : Class of systemic antimicrobial drugs

Natural : A chemicals substance produced by microorganisms and has the ability to inhibit or kill microorganisms

Question 2

Define chemotherapy

Answer 2

The use of natural or synthetic chemicals to kill bacteria, virus ,fungi ,protozoa and helminths within the human body or to inhibit their growth

or a process whereby chemicals are used to kill an abnormal growth of abnormal cells

Question 3

Define Antiseptic and disinfectants

Answer 3

• Theses are agents that kill or inhibit the growth of microorganisms in high concentrations ,they are toxic to cells and should not be administered systemically

Disinfactants -

Question 4

Define Antiseptic and disinfectants

Answer 4

• Theses are agents that kill or inhibit the growth of microorganisms in high concentrations ,they are toxic to cells and should not be administered systemically

Disinfectants - Sterilize objects in the environments

Antiseptic - Used on the skin and mucous membranes

Question 5

Selective Toxicity : The primary of chemotherapy is

Answer 5

The drugs are selectively toxic for microorganisms without negatively affecting the host cells

Absolute : Selective for microorganisms
Relatively : Depending on dose , shows more selectively to microorganism than host cells

Question 6

The exploited biochemical differences between pro and eukaryotic cells

Answer 6

*cell walls
ribosomes
unique enzymes
unique metabolic reaction

Question 7

terms are used in connection

with the working mechanism of antibiotics:

Answer 7

• Narrow spectrum : Only a few bacterial cell types are influenced
• Br

Question 8

terms are used in connection

with the working mechanism of antibiotics:

Answer 8

• Narrow spectrum : Only a few bacterial cell types are influenced
• Broad spectrum : Various bacterial cell types are influenced

Question 9

Extended Spectrum :

Answer 9

Through chemical modification,it affects additional types of bacteria usually gram negative bacteria

Question 10

Are bactericidal and bacteriostatic drugs effective chemotherapeutic drugs ?

Answer 10

yes

Question 11

What is the difference between Bactericidal and bacteriostatic drugs?

Answer 11

Bactericidal causes microbial lyses and cell death and bacteriostatic inhibits cell growth and division

Question 12

Factors affecting bacterial infection treatment

Answer 12

1.Drug retention (Drug eliminated or inactivated by host)
2.Wrong drug (Wrong spectrum of activity )
3.Drug delivery problems:
(oral=destruction or poor intake first pass metabolism)
4.Side effects ; Toxicity to host , allergic reaction or normal flora disruption)
5.Development of resistance through acquired genes or mutation
6.Toxins : Exotoxins and Endotoxins ( In gram negative septicemia antibiotics treatment can even make the situation worse )

Question 13

True or false : Bacrericidal and bacteristatic depend on the host inherent defense mechanism to remove the pathogens

Answer 13

true

Question 14

What are the factors preventing bacterial growth

Answer 14

1. Bactericidal
2. Bacteriostatic
3. Host defenses

Question 15

What is the difference between Minimal inhibitory concentration (MIC) and Minimal Bactericidal Concentration (MBC)

Answer 15

MIC is the lowest concentration of agents that prevents visible growth of bacteria after 18 to 24 hours incubation whereas MBCis the lowest concentration that results in 99% decline in bacterial numbers

Question 16

list the two types of microbial killing

Answer 16

Concentration killing and Time dependent killing

Question 17

What is the difference between Concentration and time dependent killings

Answer 17

In concentration dependent killing
rate and extent of killing
increases as drug concentration increase
.When blood levels decrease below MIC, drug is still effective .

In Time dependent killing ,killing is effective as long as serum concentration is increased during MIC dosing dosing intervals. WHEN BLOOD LEVELS DECREASE BELOW MIC, drug is not effective anymore

Question 18

Define postAntibiotic effect

Answer 18

Persistant suppression of bacterial cell growth after limited exposure to an antibiotic

Question 19

True or false: A bacteria is resistant to a drug when the drug is not affected by antibacterial growth

Answer 19

true

Question 20

True : Some metabolic characteristics of organisms are non-responsive to drug

Answer 20

true

Question 21

Discuss the multi-resistant bacteria

Answer 21

The more often antibiotics are used the greater the probability of multi-resistance cell types originating or developing

Question 22

Mechanisms of bacterial resistances

Answer 22

1. Transfer of baceria between people
2. Transferof resistant genes between bacteria
3. Transfer of resistant genes between the genetic elements within bacteria

Question 23

Biochemical mechanisms whereby

resistance develop

Answer 23

1. Production of an enzyme that inactivated the drug
2. Alterartion of drug -sensitive or drug binding sites
3. Decreased drug accumulation in bacterium
4. Development of pathway that bypasses the reaction inhibited by the antibiotics

Question 24

Causes for development of resistance

Answer 24

1. Unneccessary prescribing
2. SUB-OPTIMAL DOSS AND DURATION DURATION of therapy
3. Late initiation of therapy
4. Inapprpriate use of combination
5. Longer duration of treatment

Question 25

What is the rational choice of drugs based on

Answer 25

1.Known or likely infection microorganism 2.Sire of infection 3.Safety of agent 4.Immunestatus of the patient 4.Renal and hepatic function 5.Cost of therapy 6.Severity of infection Co-morbid disease

Question 26

List the 3 types of therapy

Answer 26

Empiric (best guess): Staring the treatment before the microorganism causing the infection is known Definitive: Based on results of microbiological tests and in vitro antimicrobial susceptibility tests Prophylatic : Preventative

Question 27

Discuss the Empiric therapy

Answer 27

Critically ill patient • Culture & sensitivity testing for serious infections • Broad spectrum agent → cover Gram positive, Gram negative and anaerobes • Multiple antibiotics for short-term (serious infections, polymicrobial infections, infective endocarditis & tuberculosis) • Bactericidal • Cover Pseudomonas aeruginosa • Good penetrability into tissue

Question 28

Discuss combined therapy

Answer 28

*A single therapy using a narrow spectrum of drugs is beneficial. Combined thereapy is only neccessary in special cases Care must be give for interactive drugs (agonistic , antagonistic ect)

Question 29

Antagonistic interaction

Answer 29

When the presence of one drug inhibits the action of another eg bactericidal (beta lactam) and bacteriostatic (tetracycline)

Question 30

Additive interaction

Answer 30

When two drug exert a combined effect which is equal to the sum of their individual effect eg beta lactam and beta lactam

Question 31

Synergistic interaction

Answer 31

The combined effect of 2 drugs is more than the sum of their individual effects ( beta lactam and aminoglycoside)

Question 32

What are the complications of antibiotic therapy

Answer 32

1. Hypersensitivity 2. Direct toxicity 3. Superinfections