This document discusses different types of antibiotics, including their definitions, indications, mechanisms of action, and resistance. It describes several classes of antibiotics: beta-lactams like penicillin and cephalosporin which inhibit bacterial cell wall synthesis; aminoglycosides which have nephrotoxicity risks; macrolides like erythromycin which are bacteriostatic; tetracyclines which can discolor teeth and bones; and metronidazole which is effective against anaerobic bacteria. Each antibiotic class has different spectrums of activity, mechanisms of action, pharmacokinetics, uses, and potential adverse effects. Precise indications and risks are outlined to help guide appropriate clinical antibiotic selection and

1. ANTIBIOTICS
Dr. Saleh Bakry
Assistant Professor of
Oral and Maxillofacial
Surgery

2. DEFINITION
Chemical compound that inhibits the
growth of microorganisms, such as
bacteria, or fungi.

3. INDICATION
Absolute indications
• Diabetics subject to "major" oral surgery.
• Immuno-compromised patients.
• Oral surgery in patients previously subject to
radiation treatment in the head and neck
region.
• Closure of oro-antral fistulae.
• Bone transplantation in oral surgery.
• Patients who have rheumatic fever.
• Patients with congenital or acquired heart
disease.

4. INDICATION
Relative indication
• Generally weak patients (patient in dialysis,
patients with other kidney diseases,
patients with leukemia).
• Treatment of complicated jaw fractures.
• Surgical intervention causing bone cavities.
• Extensive soft tissue lesions including
lesion of floor of the mouth.
• Insertion of titanium-implants.

5. MECHANISM OF ACTION OF AB
• Preventing the bacteria from producing necessary
proteins.
• Interfering with the production of metabolic
processes such as folic acid on it bacteria depend to
survive.
• Obstructing production of the bacteria's cell wall.
• Blocking both RNA and DNA synthesis.
Some antibiotics, such as the penicillins, are
'bactericidal', meaning that they work by killing
bacteria. Other antibiotics are 'bacteriostatic, meaning
that they work by stopping bacteria multiplying.

6. ANTIMICROBIAL RESISTANCE
Antibiotic resistance is the ability of a micro-organism to
withstand the effects of an antibiotic.
Mechanisms of resistance:
• As new mutations or may be transferred from
organism to organism by plasmids (DNA packages).
Antibiotic resistant bacteria:
• Antibiotic resistant germs may live in the nose or in
the bowels of healthy people.
• Antibiotic resistant bacteria are not usually harmful
to healthy people but can cause problems for those
who are seriously ill.

7. VI. DIFFERENT TYPES
OF ANTIBIOTICS

8. I. BETA LACTAM ANTIBIOTICS
• This group of antibiotics includes: penicillin,
cephalosporin, carbapenems and
monobactams.
• Beta Lactam antibiotics inhibit the growth of
bacteria by targeting the bacterial cell wall.

9. I. BETA LACTAM ANTIBIOTICS
1. PENICILLIN
Penicillin are bactericidal.
Pharmacokinetics
• Poorly lipid soluble and do not cross the blood-brain
barrier unless it is inflamed (so they are effective in
meningitis).
• Actively excreted unchanged by the kidney, this
require dose reduction in severe renal failure.
Narrow spectrum penicillin
• Narrow spectrum penicillin is only active against Gram-
positive bacteria such as Staphylococcus Aureus and
Streptococci.
• Examples include:
• Benzylpenicillin (penicillin G) is administered I.V.
• Phenoxymethylpenicillin (penicillin V) can be given orally.

10. I. BETA LACTAM ANTIBIOTICS
1. PENICILLIN
Moderate spectrum penicillin
• Moderate spectrum penicillin amoxycillin and
ampicillin, have a similar range of activity as
Narrow Spectrum Penicillin, but are more active
against bacteria of chest infections and urinary
tract infections.
Broad spectrum penicillin
• Broad spectrum penicillin consists of a special
compound combined with penicillin that protects
it against destruction by the beta lactamase
enzyme that can be produced by bacteria.
• A commonly used medication that belongs in this
group is called Augmentin Duo Forte, which can be
used to treat chest infections.

11. I. BETA LACTAM ANTIBIOTICS
2. CEPHALOSPORIN
• The cephalosporin also contains a beta lactam
ring and it is bactericidal.
• They are broad-spectrum antibiotics.
• Cephalosporins are divided into four major
groups.
• The first group of cephalosporins is active
against Gram positive bacteria.
• The second to fourth group is active against
Gram negative bacteria.

12. I. BETA LACTAM ANTIBIOTICS
2. CEPHALOSPORIN
• Third generation cephalosporins: These
antibiotics are effective in infections such as
meningitis, because they penetrate the fluid
around the brain and spinal cord.
• Fourth generation cephalosporins: This is a
very broad spectrum antibiotic, with activity
against a wide range of bacteria. It is used in
treatment of serious infections.

13. I. BETA LACTAM ANTIBIOTICS
2. CEPHALOSPORIN
Adverse effects
• Allergy.
• Nephritis and acute renal failure.
• Super-infections.
• Gastrointestinal upsets when given orally.

14. I. BETA LACTAM ANTIBIOTICS
3. CARBAPENEMS
• This class of antibiotics has a broad spectrum of
activity and is effective against many bacteria.
• However, they should be reserved for resistant
infections.
4. MONOBACTAMS
• This is another class of the beta lactam anti-
biotics, which has good activity against Gram
negative bacteria.

15. II. AMINOGLYCOSIDES
The aminoglycosides are bactericidal.
Pharmacokinetics
• Poorly lipid soluble and, therefore, not absorbed
orally.
• Unable to enter the CNS even when the meninges
are inflamed.
• Excreted unchanged by the kidney.
Examples:
• Gentamicin is covering Gram negative aerobes.
Adverse effects
• Nephrotoxicity: may cause renal failure.
• Toxic to the 8th cranial nerve (ototoxic).

16. III-MACROLIDES
• The macrolides are broad-spectrum antibiotics.
• They are bacteriostatic at usual doses but bactericidal
in high doses.
ERYTHROMYCIN
Adverse effects
• Gastrointestinal upsets (common with erythromycin)
• Rarely hypersensitivity.
LINCOSAMIDES; CLINDAMYCIN
• Clindamycin rapidly absorbed and penetrates most
tissues well, except the CNS.
Adverse effects
• Diarrhea is common.
• Pseudomembranous colitis.

17. IV. TETRACYCLINE
• The tetracycline is bacteriostatic.
These drugs:
• Are not well absorbed.
• Bind to heavy metal ions and so absorption
is greatly reduced if taken with food, milk,
antacids or iron tablets; they should be
taken at least half an hour before food.
• Concentrate in bones and teeth.

18. IV. TETRACYCLINE
Adverse effects
– Gastrointestinal upset.
– Super-infection: candidiasis.
– Discoloration and deformity in growing
teeth and bones (contraindicated in
pregnancy and in children under 12
years).
– Renal impairment (should also be avoided
in renal disease).

19. VI. METRONIDAZOLE
• It is well absorbed after oral or rectal administration
and can also be given I.V.
• It is widely distributed in the body (including into
abscess cavities) and is metabolized by the liver.
Uses:
– Active against anaerobic organisms (e.g.
Bacteroides, Clostridia).
– Used to treat pseudomembranous colitis.
– To treat a variety of dental infections, particularly
dental abscess.
Adverse effects
– Nausea, anorexia and a metallic taste.
– Ataxia, caused by peripheral neuropathy.

20. THANK YOU