Clinical Use of Antibiotics

Question 1

What is the most likely explanation for increasing antibiotic resistance in community-acquired diseases?

Answer 1

overuse of antibiotics in farming and industry

Question 2

What are the characteristics of an ideal antibacterial agent?

Answer 2

• bactericidal
• oral and injected
• long half-life and low binding to plasma proteins
• good tissue distribution to penetrate to localized sites of infection
• minimal side effects at concentrations that are bacteriocidal
• lack of adverse interactions with other drugs
• narrow spectrum (penicillin V is considered narrow spectrum)

Question 3

Order of diagnosis and treatment:

Answer 3

Always diagnose and then treat unless patient is near death

Question 4

When does bacteria resistance usually start showing after introducing a specific antibiotic therapy?

Answer 4

within several years

Question 5

Why does antibiotic resistance happen so quickly?

Answer 5

genes that code for resistance were in the gene pool before humans began to produce antibiotics

• proved via “Replica Plate” by Joshua Lederberg

Question 6

What is carbapenem?

Answer 6

B-lactam antibiotic with a broad spectrum activity against bacteria resistant to penicillins and cephalosporins

Question 7

Why is carbapenemase bad?

Answer 7

it can produce bacterial like klebsiella pneumoniae (KPC) which are highly drug resistant

Question 8

What is minimum inhibitory concentration (MIC)?

Answer 8

lowest concentration of antibiotic which prevents growth in presence of antibiotic

Question 9

What is minimum bactericidal concentration (MBC)?

Answer 9

lowest concentration of antibiotic which irreversibly kills bacteria

Question 10

T/F: bacteria in biofilms are more sensitive to antibiotics than bacteria in solution

Answer 10

False!
bacteria in biofilms are 1000 fold LESS sensitive to antibiotics than bacteria in solution

Question 11

Should antibiotics be prescribed for viral infections?

Answer 11

No!
Only prescribed for bacterial infection. Half of upper respiratory tract infections are viral so antibiotics won’t help and must weight at least 10 days before treating

Question 12

When should antibiotics be used related to dentistry?

Answer 12

facial cellulitis, aggressive acute necrotizing ulcerative, lateral periodontal abscess, acute pericoronitis with systemic signs

Question 13

When are antibiotics used prior to surgery?

Answer 13

when risk of post op infection is high, wounds are contaminated with soil/dirt, consequences of infection are serious and life threatening, and when a person’s defense against infection are compromised

Question 14

What are the 3 conditions where antibiotics aren’t recommended?

Answer 14

mitral valve prolapse, rheumatic heart disease, bicuspid valve disease

Question 15

What are the 4 conditions where antibiotics are still recommended?

Answer 15

artificial heart valves, previous history of endocarditis, congenital heart conditions, heart transplant recipients with valve problem

Question 16

If can take oral antibiotics, what should they take?

Answer 16

amoxicillin

Question 17

If unable to take oral medication, what should they take?

Answer 17

ampicillin, cefazolin/ceftriazone

Question 18

If allergy to penicillins and can take oral, what should they take?

Answer 18

cephalexin, azithromycin/clarithromycin, doxycycline

Question 19

If allergy to penicillins and unable to take oral, what should they take?

Answer 19

cefazolin/ceftriazone

Question 20

What is the most common antibiotics used in dentistry?

Answer 20

B-lactams

Question 21

Why is penicillin G used as an intramuscular injection compared to penicillin V administered orally?

Answer 21

because penicillin G is acid labile and can’t withstand gastric acid while penicillin V is acid stable so can withstand gastric acid

Question 22

Why is metronidazole also commonly used by dentists but what is the issue with it?

Answer 22

commonly used because of its activity against anaerobic bacteria (specifically used for periodontitis). deals with LOW restistance and acts by DNA damage

issue is due to major reactions when mixed with alcohol or taking blood thinners

Question 23

What is brand name of metronidazole?

Answer 23

“flagyl”

Question 24

What is metronidazole used for?

Answer 24

acute ulcerative gingivitis and progressive periodontal disease

Question 25

T/F: Clindamycin is a macrolide

Answer 25

False!
It is a lincosamide (target: ribosome for protein synthesis inhibitor) and only used in tx of high risk or bone involvement

Question 26

What are clindamycin’s side effects?

Answer 26

diarrhea is very common and can cause 4x the risk of clostridium difficile- BAD

Question 27

How does fluoride work?

Answer 27

incorporate ingested fluoride to develop into fluroapatite, AND inhibit enolases, and promotes remineralization

Question 28

Why is production of antibacterial drugs going down?

Answer 28

won’t make new antibacterials if there are antibiotics that already work

Question 29

When should cephalosporins not be used?

Answer 29

history of anaphylaxis

Question 30

If allergy to b-lactams, what are good alternatives?

Answer 30

• erythromycin, clarithromycin (macrolides)
• clindamycin (lincosamides)

Question 31

If there is known B-lactam resistance, what could be taken?

Answer 31

quinolones

Question 32

What is a good alternative for tetracycline that does not stain teeth and is recommended for pts with artificial heart valves and pregnancy and children?

Answer 32

doxycycline

Question 33

What is an antimicrobial agent for post treatment mouth rinse?

Answer 33

chlorhexidine diacetate

Question 34

What is the point of taking probiotics when on antibiotics?

Answer 34

to keep normal flora
(saccharomyces boulardii yeast)