The document discusses various classes of antimicrobial agents including their classification, mechanisms of action, spectra of activity, and examples. It covers antibiotics such as penicillin, cephalosporins, aminoglycosides, and macrolides. It also addresses antimicrobial resistance, rational antibiotic usage, and combination therapy.

1. • Dr Karishma S Halageri
1st year PG
Dept of Public Health Dentistry
Antimicrobial agents

2. CONTENTS
 Introduction
 classification of antimicrobial agents
 Selection of antimicrobial agents
 Antibiotics
 Classification of antibiotics
 Antimicrobial resistance
 Factors involved in the usage of antibiotics rationally
 Ideal antibiotics
 antibiotics combination

3. Contents
 Disadvantage and misuse of antibiotics
 Antimetabolites
 Antifungal drugs
 Antiviral drugs
 Antiprotozoal drugs
 Public health significance
 Conclusion
 References

4. Introduction
 An antimicrobial is an agent that kills or inhibits the growth of
microorganisms without harming the cells of the host. The
antimicrobial agent may be a chemical compounds and physical
agents. These agents interfere with the growth and reproduction of
causative organisms like bacteria, fungi, parasites , virus .

5. Classification of antimicrobial agents
Drugs by susceptible organisms
Antibacterial
Antiviral
Antifungal
Antiprotozoal
Anthelmintic

6. Selection Of Antimicrobial Agents
Organisms identity
and its sensitivity to
particular organism
The site of infection
The safety of the
agent
Patient factors
The cost of the
therapy

7. • Acutely ill patient
• Selecting a drug
Empiric therapy prior to organism
identification
• Blood brain barrier ,prostate
Identification and sensitivity of the
organism
• Disk diffusion method
Laboratory methods of
identification
The effect of site of infection on
therapy

8. Status of the patient
1.Immune system
2.Renal dysfunction
3.Hepatic dysfunction
4.Poor Perfusion
5.Pregnancy
6.Lactation
7.age
Safety of the agent
Cost of therapy

9. Chemotherapeutic spectra
• Agents acting on a single or limited group of
microorganisms .
Narrow spectrum
• Active against gram+ve and significant number of
gram-ve microorganims
Extended spectrum
• Affect a wide variety of microbial species
Broad spectrum

10. Antibiotics
 A substance produced by which selectively suppress
the growth of or kill other microorganisms at low
concentrations and has the capacity to inhibit the
growth of bacteria. It has a high chemotherapeutical
index to reduce the active process in bacteria . in a
diluted solution.

12. Classification of antibiotics
1. Based on chemical structures
2. Based on the sources
3. Based on mechanism of action
4. Based on spectrum of action / activity
5. Based on modes of action

13. 1. Based on chemical structures
1. Groups of sulfonamides
Sulfamethoxazole, sulfadiazine
2. Groups of Penicillin
Penicillin G (Benzyl penicillin), Penicillin V,
Ampicillin, amoxicillin, nafcillin
3. Groups of cephalosporin's
cefalotin, cefazolin, cefamandole, cefuroxime,cefotaxime, ceftriaxone.
4. Groups of aminoglycosides
streptomycin,neomycin, kanamycin, gentamycin, tobramycin
5. Groups of chloramphenicol
chloramphenicol, tiamphenicol

14. 6. Groups of tetracyclines
chlortetracycline,oxytetracycline, doxycycline, minocycline
7. Groups of macrolides
erythromycin,roxithromycin, spiramycin, azithromycin
8. Groups of polyenes
amphotericin B, nystatin
9. Groups of Lincomycins
lincomycin, clindamycin
10. Groups of polymixins
Polymyxin B, Polymyxin E

15. II. Based on the sources
a. Antibiotic from microbes
 A.B. from fungi - Penicillin from P. notatum
 A.B. from bacteria
• A.B. from eubacteria - polymyxin from bacillus polymyxa
• A.B. from micromonosporaceae - gentamyicin from
micromonospora purpurea
b. Antibiotics from algae - Usnat Acid
c. Antibiotics from higher plants - Garlisina from Allium sativum
d. Antibiotics from animals - Eritrina from hemoglobin of cow

16. III. Based on mechanism of action
A. Inhibition of cell wall synthesis leads to the death
of the bacteria lysis (bactericidal effect)
penicillin, cycloserine, vancomycin, bacitracin
B. Disruption of cell membrane function
polymyxin (polymyxin B, polymyxin E), polyenes, nystatin
C. Inhibition of protein synthesis:
This antibiotics inhibit one of the reactions in the
process of transcription
1. Inhibition of translation process of microbes

17. • Inhibit ribosome on the 30 S subunit
-streptomycin, tetracyclines, netilmycin, kanamycin
• Inhibit ribosome on the 50 S subunit
-chloramphenicol, clindamycin, lincomycin
 Inhibits the transcription process of microbes
-Rifampin, actinomycin
D. Inhibits specific metabolic reaction
 Inhibits the enzymatic reactions
-sulfonamides, INH, PAS,
trimethoprim

18. IV. Based on spectrum of action
 Broad spectrum: Effective to Gram +, Gram - bacteria, mycoplasmas,
chlamydiae, rickettsiae, sometimes protozoa
-chloramphenicol, tetracyclines
 Narrow spectrum: Effective to Gram +ve / Gram -ve bacteria only
- penicillins, cephalosporins, erythromycins, polymyxins

19. Antimicrobial resistance – WHO (2017)
 Antimicrobial resistance occurs when microorganisms such as
bacteria, viruses, fungi and parasites change in ways that render
the medications used to cure the infections they cause ineffective.
 When the microorganisms become resistant to most
antimicrobials they are often referred to as “superbugs”. This is a
major concern because a resistant infection may kill, can spread
to others, and imposes huge costs to individuals and society.

20.  Lack of government commitment to address these issues, poor
surveillance and a diminishing arsenal of tools to diagnose, treat and
prevent also hinder the control of antimicrobial drug resistance.

21. Some approaches to solve
resistance problems
1. Reduce the usage of prophylactic antibiotics
2. Use narrow spectrum antibiotics
3. Always follow directions for use of antibiotics
4. Prescribe antibiotics based on clinical situation
and not on patient’s will or pharmaceutical advertisements.
 Rational drug: drugs given after accurate
diagnosis. It will be effective with minimal side effects .

22. 1. Accurate diagnosis
2. Accurate choices of antibiotics
3. Deliver accurate dose
4. Accurate dosing interval
5. Accurate examinations of pathophysiologic conditions
of the patient
Factors involved in the usage of AB rationally,
effectively and safely.

23. Ideal antibiotics :
 Effective even in the presence of body fluids exudate,
protein or enzymes.
 Ability to reach the infected tissue, enough drug
concentration during the span of a dosing interval in blood /
infected area.
 Do not cause resistance
 Have a minimal toxic effects for the patient
 Safe for pregnancy and pediatric patients
 cost effective

24. Sensitivity tests / resistance tests
 Qualitative :
 Stokes method
 Ericcson method
 Kirby-Bauer method
 Comparison method
 Quantitative :
 MIC

25. Antibiotic Combinations :
 The result may be addictive , potentiative or antagonistic
 Addictive response :one in which the antimicrobial effect of the
combination is equal to the sum of the effects of the two drugs
alone.
 Potentiative interaction: one in which the effect of the
combination is GREATER than the sum of the effects of the
individual agents.
 Antagonistic response : in certain cases the combination of two
antibiotics may be less effective than one of the agents by itself .

26. Disadvantages of antibiotic combinations
 Increased risk of toxic and allergic reactions
 Possible antagonism of antimicrobial agents
 Increased risk of superinfection
 Selection of drug resistant bacteria
 Increased cost

28. Penicillin
 Mechanism of action: the drugs weaken the cell wall, causing
the bacterium to take up excessive amounts of water and then
rupture
 Penicillinases (beta- lactamases)
enzymes that cleave the beta-lactam ring and thereby render
penicillin and other beta-lactam antibiotics
 Classification :
 Narrow-spectrum (penicillinase sensitive)
 Narrow-spectrum that are penicillinase resistant (antistaphylococcal)
 Broad spectrum penicillin's (aminopenicillins)
 Extended spectrum penicillin's (antipseudomonal)

29. PENICILLIN G
 ANTIMICROBIAL SPECTRUM : active against most gram +ve bacteria,
gram –ve cocci (Neisseria, meningitis) and spirochetes .
With few exceptions gram –ve bacteria are resistance .
 Therapeutic uses:
• Pneumonia and meningitis caused by streptococcus pneumonia
• Pharyngitis caused by streptococcus pyogens
• Infectious endocarditis( streptococcus viridans)
• Gangrene , tetanus
• Syphilis (treponema pallidum)
 Side effects and toxicities :
• Pain at the site of infection , neurotoxicity with too high
plasma levels.
Inadvertent intra-arterial injection can produce severe reactions
(gangrene,necrosis) and must be avoided .

30. PENICILLIN ALLERGY
 Penicillin are the most common cause of drug allergy (1-10% of the patients
will experience an allergic response) there is no direct relationship
between size of dose and intensity of allergic response.
 Cross sensitivity :5-10% of patients allergic to penicillin's are also allergic
to cephalosporin's
 Types of allergic reactions:
• Immediate (occurring 2-30 min after administration)
• Accelerated (occur within 1-72 hours)
• Late reactions (days or even weeks)
• Anaphylaxis (laryngeal edema, bronchoconstriction, severe
hypotension) in 0.2% of patients ,treatment – epinephrine +
respiratory support .

31. Skin tests for penicillin allergy
Penicillin skin testing , Solensky, Franklin Adkinson Jr, Feb 2014

32. Management of patients with history of
penicillin allergy
 Ask patients for previous history of allergy to penicillin
 If the patient refers to a positive history of allergy AVOID
PENICILLIN entirely
 If the allergy is mild a CEPHALOSPORINE is appropriate as
alternative.
 If the allergy is severe avoid CEPHALOSPHORINS
 For many infections VANCOMYCIN AND ERYTHROMYCIN are
effective and safe .

33. Penicillinase-resistant Penicillin’s
 Antistaphylococcol
Resistance to beta lactamases .
Acid labile : Methicillin, nafcillin, cloxacillin, dicloxacillin
Acid resistant: flucloxacillin.
 Broad spectrum penicillin’s
 Aminopenicillins
 Ampicillin :( SPECTRUM: bordetella pertussis , E coli , salmonella ,
shigella )
Adverse effects – rashes (4-10% with ampicillin)
diarrhoea

34. EXTENDED SPECTRUM PENICILLINS
 Used to treat infections with Pseudomonas Aeruginosa (ie Ticarcillin)
 Penicillins combined with beta lactamase inhibitor
ie Amoxicillin + clavulanic acid = Augmentin
a.Carboxypenicillins : Carbenicillin, ticarcillin,
b. Aminopenicillin : Amipicillin, amoxicilllin.
c. Ureidopenicillin : Mezlocillin, piperacillin.

35. CEPHALOSPORINS
 Broad spectrum antibiotics with low toxicity
 mechanism of action : disruption of cell wall synthesis
and consequent lysis of cell .

36. CEPHALOSPORINS
First generation-
More active
Second
generation-
Third generation Forth generation
More active
against
gram positive
organism
more selective
against gram
positive and
gram negative
organisms
Highly active
against gram
negative
organisms
similar
antibacterial
activity as that 0f
third generation
but highly
resistant to beta
lactamases
Parenteral-
Cephalothin
Cefazolin
Cephaloridine
Oral-
Cephalexin
Cephadine
Cefadroxil
Parenteral
Cefuroxime
Cefoxitin
Oral
Cefaclor
Cefuroxime acetyl
Parenteral-
Cefotaxim
Ceftizoxime
Ceftriaxone
Cefoperazone
Oral
cefexim
Parenteral-
Cefepime
Cefiperome

37. Adverse effects
 Allergic reactions : rash that develops after days of treatment
severe immediate reactions are rare.
 Bleeding : five cephalosporins cause bleeding tendencies
(cefamandole , cefmentazole, cefoperazone , cefotetan and
moxalactam )
2 mechanism involved :
-reduction in prothrombin levels and
- impairment of platelet aggregation .
(only with moxalactam )
 Thrombophlebitis : it may develop during IV infusion (>change in infusion
site)
 Pain at site of IV infusion

38. IMIPENEM
 Relatively new beta-lactam antibiotic with very broad spectrum.
 Antimicrobial spectrum : highly active against gram +ve and gram-ve cocci .
 It is also the most effective beta-lactam antibiotic against anaerobic bacteria.
 Pharmacokinetics
it is not absorbed from the GI tract .
IV or IM administration .
 Adverse effects
(generally well tolerated)
• GI effects (nausea, vomiting , diarrhoea)
• Hypersensitivity reactions (rashes ,pruritus )
• Superinfections with bacteria or fungi develop in about 4%of patients .
• Rarely seizures have occurred

39. Bacteriostatic Inhibitors Of Protein Synthesis
 Aminoglycosides
 MLSK (Macrolides, Lincosamides, Streptogramins, Ketolides)
 Tetracyclines
 Glycylcyclines
 Phenicols
 Ansamycins

40. Aminoglycosides
• Action: severe infections
• MOA :Disruption of bacterial Protein Synthesis
• Antimicrobial spectrum: aerobic gram-ve bacilli(E.Coli,
klebsiella, pneumonia, proteus mirabilis, pseudomonas
aeruginosa)
the drugs are inactive against most gram+ve bacteria
the drugs are ineffective against anaerobes.
• Potential for serious AE
ototoxicity, nephrotoxicity
• Not given orally due to their poor absorption
• Low dose: bacteriostatic
• High dose: bactericidal
• Gentamicin , tobramycin, amikacin

41. Macrolides
 MOA: bind to the 23S rRNA in the 50S subunit ribosome
inhibiting protein synthesis
 Dose: 250-500 mg/day x 5-10 days
 anti bacterial spectrum – similar to penicillin (against gram+ve bacteria
and against some gram-ve )
 against penicillin resistant staphylococci.
 partially destroyed by gastric juice, (enteric coated tablets)
• Various preparation- enteric coated tablets
Estolate form (most resistant by gastricacid)
• Drugs belonging to this group- erythromycin, olindomycin, Spiramycin

42.  New macrolides- roxithromycin, clarithromycin
 Similar spectrum of erythromycin
 More resistant to acid hydrolysis.
 Better tissue level are achieved
 Therapeutic uses:
 Legionella pneumophila pneumonia (legionnaires disease)
 Whooping cough (bordetella pertussis)
 Corynebacterium diptheriae (diphtheria)
 Chlamydial infections
 Mucoplasma pneumonia
 Alternative to penicillin G in penicillin allergy

43.  Adverse effects
GI effects (nausea , vomiting , diarrhoea)
liver injury (cholestatic hepatitis . Happens with erythromycin estolate
in adults with pre existing history of liver disease )
 Drug interactions :
CAUTION WHEN combined with astemizole and terfenadine
(antihistamines) , theophylline , warfarin(anticoagulant), carbamazepine
(anticonvulsant)
 Erythromycin antagonises the effect of chloramphenicol and
clindamycin .

44. Lincosamides
Clindamycin (Cleocin)
 MOA: binds to the 50S ribosomal subunit and inhibits protein synthesis
 Antimicrobial spectrum : anaerobic bacteria (gram-ve and gram +ve)
 Widely distributed in tissue fluids and tissues, including bone.
 Avoid in the routine odontogenic infection
 An excellent alternative drug in penicillin-resistant anaerobic infections
 Used in Osteomyelitis of the jaws
 Dose: 100-450mg 6 h x 7-10 days
 Adverse events: -GI upset, pseudomembranous colitis
(symptoms include profuse watery diarrhoea ,abdominal pain fever and
leucocytosis)
- hypersensitivity reactions (rashes)
 Drug interactions: neuromuscular blocking agents

45. Tetracycline
 Broad spectrum antibiotic.
 MOA: Suppression of bacterial growth by inhibiting protein synthesis
 Low absorption through GIT.
 Rapid renal excretion
 Therapeutic uses
 Treatment of infectious diseases (rickettsial diseases – rocky mountain
spotty fever , typhus fever , Q fever )
 Infections caused by chlamydia trachomatis , brucellosis , cholera ,
pneumonia caused by mucoplasma pneumonia , lyme disease .

46.  Gastric infections with helicobacter pylori
 Treatment of acne (orally and topically for severe acne vulgaris )
 Peptic ulcer disease (combination of tetracycline's, metronidazole
and bismuth salicylate against helicobacter pylori )
Absorption : the drugs should not be administered together with
-calcium supplements
-milk products and iron supplements
-magnesium containing laxatives
-antacids

47. Adverse Effects Of Tetracyclines
 Gastrointestinal irritation(nausea , vomiting , diarrhoea )
 Effects on bones and teeth (teeth discolouration in children under 5 years
old
the drugs can also supress long –bone growth )
 Superinfection (C. difficile pseudomembranous colitis ,fungus infections
usually with candida albicans
 Hepatotoxicity(fatty infiltration of the liver)
 Renal toxicity (the drugs may exacerbate renal dysfunction in patients
with pre-existing kidney dysfunction )
 Photosensitivity

48. Doxycycline (Vibramycin)
 MOA: inhibit protein synthesis by preventing aminoacyl transfer
RNA from entering the acceptor sites on the ribosome
 Dose: 100mg bid x 7-14 days
 High potency.
 Complete absorption from intestine.
 High plasma binding.
 Contraindications: - Food
- pregnancy
 Drug interactions: anti-epileptics

50. Antibiotics commonly used in odontogenic
infections

52. 4. Anti - Metabolites
•Sulfonamides
•Trimethoprim

53. Sulfonamides
 MOA: suppression of bacterial growth by inhibiting synthesis of folic acid
 Antimicrobial spectrum : Enterococcus –poorly expressed , S. pneumonia ,
Ps. aeruginosa
 THERAPEUTIC USES : urinary tract infections .
 Adverse effects :
• Hypersensitivity reactions (rashes , drug fever , photosensitivity )
• Hematologic effects (haemolytic anaemia in patients with G-6PD deficiency)
• Kernicterus
• The drugs should not be given to infants under the age of 2months,
pregnant and breast feeding mothers

54. Trimethoprim
 MOI: Inhibitor of dihydrofolate reductase ( suppresses bacterial
synthesis of DNA ,RNA and proteins
 Therapeutic uses :
It is approved only for the initial treatment of acute uncomplicated urinary
tract infections due to susceptible organisms
(E.coli,proteus mirabilis etc )
 Adverse effects :
• Generally the drug is well tolerated
• Most common adverse effect include itching and rash
• GI reactions occur occasionally
 Caution when administering the drug to patients with suspected folate
deficiency – increase danger of bone marrow suppression

55. Fluoroquinolones
 Ciprofloxacin (Cipro), Garenoxacin
 MOA: Inhibition of DNA gyrase
 Antimicrobial spectrum: Gram-negative and Gram-positive ( Anaerobes,,
S.pneumoniae and Pseudomonas)
 Dose: 250-500 mg qid x 7-10 days
 Contraindications: <18 yrs old, pregnancy
 Adverse events: spontaneous tendon rupture
 Drug interactions: probenecid, warfarin
 Ciprofloxacin, Levofloxacin, Norfloxacin, Ofloxacin
Spectrum -Staphylococci, Streptococci and Pneumococci (sporfloxacin).
 More widespread tissue distribution

56. Antifungal Agents
Major antifungal drugs comes from three families
 Polyenes (Amphotericin B)
 Imidazole's (ketoconazole , miconazole)
 Antimetabolites (flucytosine)

57. Classification of antifungal drugs
Topical Systemic
Amphotericin B Amphotericin B
Carbol-Fuchsin Dapsone
Clotrimazole Fluconazole
Econazole Flucytosine
Ketoconazole Griseofulvin
Nystatin Itraconazole
Silver Sulfadiazine Ketoconazole
Oxiconazole Miconazole
Miconazole KI (Potassium Iodide)

58. Amphotericin B
 Obtained from Streptomyces nodosus
 It is a member of the polyene family of antibiotics
 Administered by IV infusion with 5%dextrose (0.1mg/ml) or
(0.3mg/ml)
 Can be applied topically as a 3%cream ,ointments or lotion is useful in
treatment of superficial candida infections .
 Adverse effects:
 Local irritation
 gastrointestinal disturbances
 Hypotension
 Renal toxicity
 Delirium along with fever, nausea ,abdominal pain , anorexia

59. AZOLE DERIVATIVES
 Clotrimazole (Mycelex), ketoconazole (Nizoral), fluconazole (Diflucan)
 MOA: inhibit cell wall synthesis
 Dose: 100mg 6.5 h; 200mg 8.5h; 300mg 9.6h
 Therapeutic uses:
-blastomycosis
-histoplasmosis
-effective against chronic mucocutaneous candidiasis
-successful treatment of oral candidiasis by systemic ketoconazole
 ADVERSE EFFECTS :
-anorexia
-epigastric pain
–GI upset
-hepatotoxicity
-adrenocortical suppression with high doses
 Drug interactions: major p-450 enzyme inhibitor

60. TREATMENT OF ORAL CANDIDIASIS
Clotrimazole troches 10 mg ,dissolve 1 troche in mouth 5
times a day for 14 days
Nystatin oral suspension 500,000 units: Swish 5 mL in mouth
then swallow (optional), 4 times a day
for 14 days
Nystatin pastilles 100,000 units: dissolve 1 in mouth 4
times a day for 14 days
clotrimazole 1% cream
 Topical agents (mild to moderate oral candidiasis)

61. Systemic agents
Fluconazole 100 mg: Dispense 15 tablets, take 2 tablets on day
1,
followed by 1 tablet a day for the remainder of the
14-day treatment period
Itraconazole oral
suspension
10 mg/10 mL: Dispense 140 mL, swish and
swallow
10 mL per day for 7 to 14 days.
Voriconazole 200 mg: Dispense 14 tablets, take 1 tablet twice
daily
for 2 weeks or at least 7 days following resolution
of symptoms

62. Antiviral Drugs
• Viruses have no cell wall and made up of nucleic acid
components
• Viruses are obligate intracellular parasite
• They do not have a metabolic machinery of their own –uses host
enzymes
• Certain viruses multiply in the cytoplasm but others do in
nucleus
• Most multiplication take place before diagnosis is made

63. Antiviral Medications
 Antiviral drugs
Used to treat infections caused by viruses other than HIV
 Antiretroviral drugs
Used to treat infections caused by HIV, the virus that causes
AIDS
 Herpes-Simplex Viruses
- HSV-1 (oral herpes)
-HSV-2 (genital herpes)
 Varicella Zoster Virus
Chickenpox
Shingles

64. Antiviral drugs : nonretroviral
 Mechanism of action
Inhibit viral replication
 Used to treat non-HIV viral infections
Influenza viruses
HSV (herpes simplex virus), VZV (varicella zoster virus)
CMV (cytomegalovirus)
Hepatitis A, B, C (HAV, HBV, NCV)
 Adverse Effects
Vary with each drug
Healthy cells are often killed also, resulting in serious toxicities

65. Antiviral spectrum ,MOA and clinical uses of
antiviral drugs
Agent Antiviral
spectrum
Mechanism of action Clinical uses
Amantidine,rimantidine Influenza A virus Blockade of uncoating
process
Prophylaxis of influenza A infection .
Idoxuridine HSV Inhibition of DNA synthesis Treatment of herpetic keratitis
Vidarabine , trifluridine HSV Inhibition of DNA synthesis Treatment of herpetic keratitis and
keratoconjuctivitis
Penciclovir HSV Inhibition of DNA synthesis Treatment of recurrent herpetic
labialis
Acyclovir HSV and VZV Inhibition of DNA synthesis Treatment of primary and recurrent
herpetic infections , mucocutaneous
herpetic infections in
immunocompromised patients ,VZV
infections ,herpetic encephalitis

66. Agent Antiviral
spectrum
Mechanism of action Clinical uses
Foscarnet HSV, VZV, CMV Inhibition of DNA synthesis Treatment of CMV retinitis and
acyclovir resistant HSV and VZV
infections
Ribavirin RSV inhibition of DNA synthesis ,
purine metabolism
Treatment of RSV pneumonia and
bronchitis
Reverse
transcriptase
inhibitors
HIV Inhibition OF DNA synthesis Treatment of HIV infection and AIDS
Protease
inhibitor
HIV Blockade of HIV protease Treatment of HIV infection and AIDS

67. Antiprotozoal drugs

68. Metronidazole
 Uses :
-anaerobes in intra abdominal abscess
-bone and joint infections ,septicaemia
-peptic ulcer disease
-endometritis
• In Periapical abscess , periodontal abscess , acute pericoronitis
of impacted or partially erupted teeth : often used in
conjugation with Amoxicillin .
• Primary agent used in ANUG 500mg TID for 5-7days
 ADVERSE EFFECTS :
nausea ,diarrhoea ,metallic taste
infrequent adverse effects : hypersensitivity reactions,
headache ,vomiting , CNS toxicity in long term systemic use

69.  Triple Antibiotic Paste
 metronidazole, ciprofloxacin, and minocycline
 combination would be needed -diverse flora in root canal
 metronidazole -at a high concentration, it cannot kill all the bacteria, indicating the
necessity for combination of other drugs
 Metronidazole (nitroimidazole) -a broad spectrum against protozoa &anaerobic
bacteria.
 Minocycline (semisynthetic tetracycline) with a similar spectrum of activity.
 Ciprofloxacin, a synthetic fluoroquinolone, has a bactericidal mode of action
 Increase in root thickness and length, resembling normal maturation of the root. the
infected area requires a normal blood supply which is no longer in necrotic pulps.
 Therefore, local application of antibiotics most effective mode for delivering the
drug. •30% reduction in bacteria -2 weeks.
 successful treatment- sterilization of canals and healing of periapical pathology,
 immature root development, necrotic pulps, and apical periodontitis
 •drawbacks of this technique- Development of resistant bacterial strains and tooth
discoloration
J Phrm Bioallied Science Aug 2012,4(suppl2) S230-233

70. New era of antimicrobial therapeutics
 There has been an urgent need for new avenues of therapeutic
treatment, and a new era of prophylytic (preventative) treatment
has begun. Here the most plausible approaches are :
-antimicrobial peptides
-bacteriophage therapy
-bacterial vaccines
-cationic peptides
-cyclic D,L-a-peptides
-Bacterial interference

71. Newer antimicrobial agents in use
 Newer Antibiotics in Use
 Cefepime- 4th Generation cefalosporin
 Aztreonam
 Linezolid
 Tigecycline
 Teicoplanin
 Levofloxacin/Moxifloxacin
 Imipenem/Meropenem
 Daptomycin
 Tigecycline
 Dalfopristin-quinupristin

72.  Newer antifungals in use
• Voriconazole, ravuconazole, and posaconazole
• Echinocandins and pneumocandins are a new class of antifungals
• Acylhydrazones
 New antivirals in use
• Doravirine
• Ribavirin
• Phosphonoformate

73. Public Health Significance
 Only little is known about the occurrence, fate, effects and risks
associated with the release of antibiotics and other drugs into the
environment. There is still a lack of fundamental data on the occurrence,
fate and effects of antimicrobials in the environment needed for proper
risk assessment and risk management both for humans and the
environment.
 Although antibiotics are used by patients outside hospitals, in livestock
attention should also be paid to their use in hospitals.

74.  Emergence of resistance to multiple antimicrobial agents in pathogenic bacteria
has become a significant public health threat as there are fewer, or even
sometimes no, effective antimicrobial agents available for infections caused by
these bacteria.
Gram‐positive and Gram‐negative bacteria are both affected by the emergence
and rise of antimicrobial resistance.
 Increasing resistance to antimicrobial agents that are important in the treatment
of human diseases, such as fluoroquinolones and third-generation
cephalosporins for the treatment of Salmonella and Campylobacter infections,
has significant public health implications

75. Awareness about antimicrobial resistance
Medical
colleges
&health
educatio
n

77. CONCLUSION
 The therapeutic benefit of antimicrobial agents should be
balanced with their unintended adverse consequences.
 Inappropriate antibiotic use is associated with antibiotic
resistance and Clostridium defficile infections,
 Antimicrobial drugs prescribing should be prudent,
thoughtful and rational.

78. References
 Goodman & Gilman .The pharmacologic basis of therapeutics :2011:12th
edition:1365-1382
 K.D.Tripathi Essentials of Medical Pharmacology:2013:7th edition:702-930
 Franklin S.Weine.Endodontic Therapy:2003:6th edition:450-560
 Freifeld AG, Bow EJ, Sepkowitz KA, Boeckh MJ, Ito JI, Mullen CA, Raad II,
Rolston KV, Young JA, Wingard JR. Clinical practice guideline for the use of
antimicrobial agents in neutropenic patients with cancer: 2010 update by the
Infectious Diseases Society of America. Clinical infectious diseases. 2011 Feb
15;52(4):e56-93.ntology 2000. 2002 Jan;28(1):106-76.
 Cohen ML. Epidemiology of drug resistance: implications for a post—
antimicrobial era. Science. 1992 Aug 21;257(5073):1050-5.

79. References
 Lorian V, editor. Antibiotics in laboratory medicine. Lippincott Williams &
Wilkins; 2005.
 Taneja N, Rao P, Arora J, Dogra A. Occurrence of ESBL & Amp-C [beta]-
lactamases & susceptibility to newer antimicrobial agents in complicated UTI.
Indian Journal of Medical Research. 2008;127(1):85.
 Anderson AD, Nelson JM, Rossiter S, Angulo FJ. Public health consequences of
use of antimicrobial agents in food animals in the United States. Microbial
Drug Resistance. 2003 Dec 1;9(4):373-9