role of antibiotic 1

Role of Antibiotics In Exodontics

Dr.V.RAMKUMAR

CONSULTANT DENTAL &FACIOMAXILLARY SURGEON

REG NO:4118 -TAMILNADU –INDIA( ASIA)

History

• Pasteur & joubert ( 1877)

• Modern era (1936) sulfanilamide

• Golden year (1941) penicillin.

Definition

• Antibiotics are substances produced by microorganisms, which suppress the growth of or kill other microorganisms at very low concentrations.

Classification

1. On the basis of preparation :i. Naturally occurring, e.g. from fungi, e.g. penicillins, cephalosporins,

erythromycin, tetracycline, chloramphenicol, and aminoglycosides, etc.

ii. Synthetic, e.g. sulfonamides.

2. On the basis of family:i. Penicillinsii. Cephalosporinsiii. Sulfonamidesiv. Tetracyclinesv. Aminoglycosidesvi. Macrolide

3. On the basis of spectrum of activity:i. Narrow: penicillins

ii. Broad: ampicillins, tetracyclines.

4. On the basis of effect:i. Bacteriostatic: erythromycine, tetracycline, sulfonamide,

etc.

ii. Bactericidal: penicillins, cephalosporins, etc.

5. On the basis of their effect on Gram-positive or Gram-negative bacteria:

i. Antibiotics acting on Gram-positive bacteria: penicillins, cephalosporins, erythromycine, bacterim, tetracycline,

gentamicin, etc.

ii. Antibiotics acting on Gram-negative bacteria: penicillin acts on gonococci.

6. On the basis of systems:

i. Urinary tract:

– Nalidixic acid: acts on kidney and urinary bladder

– Furadantin: acts on bladder

ii. Skin : Neomycin, bacitracin, polymyxin.

iii. Orally (locally): neomycin, streptomycin.

Antimicrobial vs Antibiotic

Confusion regarding antimicrobialand antibiotic !!

Mechanisms by which antibiotics may inhibit growth and multiplication :Alteration of cell membrane permeabilityAlteration in synthesis of cellular componentInhibition of Cellular metabolism

Sites of action

Inhibiting formation of the bacterial cell wall

Inhibiting bacterial protein synthesis

Inhibiting nucleic acid synthesis

Altering the permeability of cytoplasmic membranes

Factors influencing the efficacy:

Drug bindingProtection of pathogensTotal bacterial loadEffectiveness of host defensesPathogens in the periodontal tissues, root canals and other oral sites not affected by the therapy

Systemic and Topical antibiotics

What to use and Where ??

Rationale of antibiotic usage

Microbial etiology Concept based on the premise….Patients who do not respond to mechanical therapy

Thus the concept of antibiotic therapy centers upon the pathogenic microbiota, the patient and the drug

3 ways : Empirical therapy

Definitive therapy Prophylactic-against specific organisms-high risk-In general

Uses in dentistry and their side effects

Choice of an antibiotic :

Patient factors :1.Age

2. Dose modification :

3. Local factors : Pus Hematomas Ph Anaerobic environment4. Drug allergy

5. Impaired host defence

Organism related considerations:

• Clinical diagnosis itself directs…• Choice

Combination therapySynergismTo reduce severity or incidence of adverse effectsPrevent resistanceTo broaden the spectrum of antibiotic action

“Good decisions improve the chances of successful outcomes”

Various antibiotics

QUINOLONES

• Synthetic

• Having a quinolone structure

• Primarily active against Gm–ve bacteria

• Newer fluorinated compounds also inhibit Gm+ve ones

• 1st member nalidixic acid in mid 1960s

Fouoroquinolones

• Quinolones antimicrobials having one or more fluorine substitution.

• First generation Fouoroquinolones –

• Second generation Fouoroquinolones -

Norofloxacin Ofloxacin

Ciprofloxacin Pefloxacin

Lomefloxacin Levofloxacin

Sparfloxacin Gatifloxacin

Moxifloxacin

Beta Lactam Antibiotics

These are antibiotics having a β-lactam ring. The two major groups are pinicillins and cephalosporons.

PENICILLINS

• Penicillin was the first antibiotic to be used clinically in 1941. it is a miracle that the least toxic drug of its kind was the first to be discovered. It was originally obtained from the fungus Penicillium notatum, but the present source is a high yielding mutant of P.chrysogenum.

Semisynthetic Penicillin

Classification –1. Acid resistant alternative to penicillin G phenoxymethyl

penicillin (Penicillin V).2. Penicillinase resistant penicillins Methicillin, Oxacillin,

Cloxacillin.3. Extended spectrum penicillins

a) Aminopenicillins: Ampicillin, Bacampicillin, Amoxicillin.b) Carboxypenicillins: Carbenicillin, Carbenicillin indanyl,

Carbenicillin phenyl (Carfecillin), Ticarcillin.c) Ureidopenicillins: Piperacillin, Mezlocillin.d) Micillinam (Amdinocillin).

β-lactamase inhibitors Clavulanic acid Sulbactam.

Cephalosporins

• These are a group of semisynthetic antibiotics derived form ‘cephalosporin-C’ obtained from a fungus Cephalosporium. They are chemically related to penicillins; the nucleus consists of a β-lactam ring fused to a dihydrothiazine ring.

First generation

Second generation

Parenteral

Cephalothin

Cefazolin

Oral

Cephalexin

Cephradine

Cefadroxil

Parenteral

Cefuroxime

Cefoxitin

Oral

Cefaclor

Cefuroxime axetil

Third generation

Fourth generation

Parenteral

Cefotaxime

Ceftizoxime

Ceftriaxone

Ceftazidime

Cefoperazone

Oral

Cefixime

Cefpodoxime procetil

Cefdinir

Ceftibuten

Parenteral

Cefpime

Cefpirome

• All cephalosporins are bactericidal and have the same mechanism of action as penicillin, i.e. inhibition of bacterial cell wall synthesis.

Tetracyclines and Chloramphinicol(Broad Spectrum Antibiotics)

Aminoglycoside Antibiotics

These are a group of natural and semisynthetic antibiotics having polybasic amino groups linked glycosidically to two or more aminosugar (streptidine,2-deoxy streptamine, garosamine residues).

Macrolide and Other Antibacterial Antibiotics

MACROLIDE ANTIBIOTICS

• These are antibiotics having a macrocyclic lactone ring with attached sugar. Erythromycin has been in use from the 1950s, Roxithromycin, Clarithromycin and Azithromycin are the recent additions.

Erythromycin

Mechanism of action

• Erythromycin is bacteriostatic at low but cidal at high concentrations.

Adverse effects

1. Gastrointestinal

2. Very high doses of erythromycin have caused reversible hearing impairment.

3. Hypersensitivity

MISCELLANEOUS ANTIBIOTICS

• Clindamycin

• Vancomycin

Principles for choosing ANTIBIOTICS!!!!!

• IDENTIFICATION OF THE CAUSATIVE ORGANISM• DETERMINATION OF ANTIBIOTIC SENSITIVITY• SPECIFIC, NARROW SPECTRUM – Ab • LEAST TOXIC Ab• Pt’s DRUG HISTORY• BACTERICIDAL RATHER THAN

BACTERIOSTATIC• Ab WITH PROVEN HISTORY OF SUCCESS• COST OF Ab

+

+

+

+

ANTIBIOTIC ADMINISTRATION

• Proper dose

• proper time interval

• Proper route of administration

• Combination antibiotic therapy

Causes of failure

• Inadequate surgical treatment• Depressed host defence• Prence of foreign body• Antibiotic problems

– drug not reaching infection– Dose not adequate– Wrong bacterial diagnosis– Wrong antibiotics

Classification of wounds ( CCSC )

Class I (Clean) – Non-Traumatic or surgical

Class II (Clean contaminated) – Fresh

Class III ( Contaminated )

Class IV ( Dirty )

Class I – No Antibiotics

Class II – Rarely / depressed host, prosthetic device infection prolonged surgery and reduced blood supply.

Class III & IV - Antibiotics

When to

use?????

Prophylactic antibiotics

• J F Burke – 1961

• MIC 15 To 30 mints(Iv)s

Indications of prophylactic Ab

• Endocarditis• Valvular heart diseases• Total joint replacement• ESR• Prosthetic valves• DM• Leukemia • COL • Immunosuppressed patients

Prophylactic regimens for dental procedures

Situation Antibiotic Regimen

• Standard general prophylaxis

Amoxicillin Adults, 2.0 g; children, 50 mg/kg orally one hour before procedure

• Can not use oral medications

Ampicillin Adults, 2.0 g IM/IV; children, 50 mg/kg IM/IV within 30 minutes before procedure

Contd..

• Allergic to penicillin

Clindamycin

or

Cephalexin

Cephadroxil

or

Azithromycin or Clarithromycin

Adults, 500 mg; children, 20 mg/kg

orally one hour before procedure

Adults, 2.0 g; children, 50 mg/kg

orally one hour before procedure

Adults, 500 mg; children, 15 mg/kg orally one hour before procedure

• Allergic to penicillin and unable to take oral medications

Clindamycin

or

Cephazolin

Adults, 600 mg; children, 15 mg/kg IV

one hour before procedure

Adults, 1.0 g; children 25 mg/kg IM/IV within 30 minutes before procedure

Antibiotics-The Miracle drugs

Use, Misuse and Abuse

Misuse of antibiotics :

Inappropriate antibiotic

Failure to take the entire prescribed course

Saving antibiotics for a future illness

Sharing or using someone else’s medicine

Era of antibiotic on demand

False sense of security

Over the counter availability (self medication)

Is antibiotic misuse a serious problem ?

Antibiotic misuse can lead to the development of antibiotic-resistant bacteria.

Misusing antibiotics means they may not be effective when needed to treat an infection in the future.

Abuses :

Humans have ignored a clear warning that excessive or abuse of antibiotics would lead to a world filled with human carriers of bacteria resistant to known antibiotics

Broad spectrum and long courses of therapyProphylactic use for simple surgical procedures

“When in doubt cover”Well defined limited infectionsPain

“Selective pressure phenomenon”

Emerging Antimicrobial Resistant Organisms: The Global Problem of Antibiotic Misuse

Adaptations (product of selection)Acquisition and transmission of antibiotic

resistance (horizontal gene transfer)

Mechanisms:1. Mutation2. Destruction or inactivation3. Efflux

Development of resistance

• Mutation

• Transduction

• Transformation

• conjugation

How to prevent abuse ??

Sufficient risk of infection morbidityBactericidal antibiotics are preferred …

Narrow spectrum antibiotic effective

Dosages should not be reduced.

Aggressive antibiotic protocol in immuno- compromised patients

Close up follow up of patients with infection

Difficult chronic and sub acute infections

How to prevent antibiotic abuse

Most appropriate

Maintain high enough levels of the drug

No “Just in case”

2 or more drugs to be administered

Restrict use of drugs

Strictly regulate the amplification of drug resistance

Policy for antibiotic use

Surveillance systems

Educational and Compliance programs

Solutions for bacterial resistance :

Research

Quality control in pharmaceutical production

Other modalities : “Decoy molecules”

Summary and Conclusion

Can we instead be facing the end of golden era of antibiotics ??

Thank YouHave a Nice Day…..