ANTIMICROBIAL THERAPY

1
Introduction to Antimicrobial Drugs
2
Classification by Susceptible Organism

• Antibacterial
• Antiviral
• Antifungal
• Antiprotozoan
• Anthelmintic

3
Mechanism Of Action

• Inhibition of bacterial cell wall synthesis
• Inhibition of protein synthesis
• Inhibition of nucleic acid synthesis
• Inhibition of metabolic pathways
• Disruption of cell membrane permeability
• Inhibition of viral enzymes

4
Direct Exam Of Tissue Secretions

• Gram stain
• Morphology
• Use of special reagents, stains
• Cultures
• Common organisms and identification

5
Diagnosis Of Infection

• Signs and symptoms
• fever, increased WBC, pain, inflammation,
  erythema
• Microscopic exam of fluids
• CSF, urine, blood
• Identification of organism
• culture, sensitivity

6
Empiric Therapy

• The antibiotic selected is one that can best
  kill the microorganisms known to be the most
  common cause of infection

7
Empiric Therapy Selection

• Patient Characteristics
• age, immune function, other disease states,
  pregnancy, renal/hepatic function
• Site of Infection
• Drug Characteristics
• efficacy, side effects, tissue penetration, cost

8
Prophylactic Therapy

• The antibiotic given when there is likelihood
  of microorganisms being present and used to
  PREVENT infection

9
Antimicrobial Resistance

• Production Of Drug-inactivating Enzymes
• Mrsa
• Vre
• Tb

10
General Considerations

• ID of the pathogen
• Drug susceptibility
• Drug spectrum
• Drug dose
• Period of time to affect the pathogen
• Site of infection
• Patient assessment

11
Agent Classification

• Narrow-spectrum
• Causative agent known through culture

• Extended-spectrum
• Specific causative agent not known

12
General Side Effects

• Hypersensitivity
• Toxicity to various organs kidney, liver, skin,
  bone marrow
• Suprainfection

13
General Nursing Implications

• Assess results of CS or that culture has been
  done before starting antibiotic
• Instruct client to take all medication
• Use another type of Bc
• Monitor blood levels
• Peak
• Trough

14
Continued

• MONITOR CBC (WBC and differential)
• If severe diarrhea, instruct client to drink
  buttermilk/yogurt to replace flora
• Know difference
• Bacteriostatic
• Bactericidal

15
Nursing Process

• Assessment
• Nursing Diagnosis
• Planning
• Intervention
• Evaluation

16
Antibiotics Affecting The Bacterial Cell Wall

• PENICILLINS
• Derived from fungus
• Beta-lactamases
• Bactericidal
• Penicillin G narrow spectrum
• Aminopenicillins broad-spectrum
• Commonly destroys gram
• Streptococcus, staphylococcus

17
Major Side Effects

• Most common SE are GI
• Rash on abdomen, scalp, or armsusually first
  sign of allergy
• Hematologic reactions decreased hemoglobin,
  prolonged bleeding
• NSAIDS protein-bound/compete
• Decreased effect of BCP

18
Combination Products

• Clavulanic acid, tazobactam, sulbactam
• Bind to enzymes active site and allow antibiotic
  to reach target site
• Augmentin,Unasyn

19
Cephalosporins

• Introduced in 1960s
• Similar to penicillins, bactericidal
• 4 generations of drug, each with different
  spectrum
• If allergic to penicillins, may be allergic to
  cephalosporins (1-18)

20
Cephalosporins

• 1st generation
• Gram
• Skin infections
• take with food to decrease GI upset

• 2nd generation
• gram and gram -
• low cost
• broad range of organisms

21
Cephalosporins

• 3rd generation
• Works best against Gram -
• severe infections and immuno-compromised patients
• SE bleeding, no alcohol

• 4th generation
• Active against Gram , -
• highly resistant to to destruction by
  beta-lactamases (both 3rd and 4th)

22
Antibiotics Affecting Protein Synthesis

• Aminoglycosides
• Macrolides

23
Aminoglycosides

• Action severe infections
• Potential for serious AE
• ototoxicity, nephrotoxicity
• Not given orally due to their poor absorption
• Low dose bacteriostatic
• High dose bactericidal
• Use primarily for Gram -
• Monitor peak and trough

24
Macrolides

• Bacteriostatic and high doses is bactericidal
• Common AE GI upset, hepatotoxicity
• Interacts with warfarin, cyclosporin,
  carbamazepine
• Common drugs erythromycin, clarithromycin,
  azithromycin

25
Tetracyclines

• Inhibit the growth of bacteria, does not kill
  them
• Uses Gram , -, broad spectrum
• Contraindicated for use in children under 8,
  pregnant or nursing women
• Major AE GI upset, hepatotoxicity, stained
  teeth, superinfections

26
Miscellaneous Antibiotics

• Fluoroquinolones
• Sulfonamides

27
Fluoroquinolones

• Very broad-spectrum antibiotic.
• Kill rather than inhibit.
• Cipro is most active against aerobic gram -
  organisms.
• Not indicated for children under 18 or pregnant
  women.
• Adverse effects arthropathy, GI upset, HA,
• Give on an empty stomach.

28
Sulfonamides

• Bacteriostatic
• Primarily used to treat UTI because of high
  concentrations in kidneys
• Major AE nephrotoxicity, photosensitivity,
  allergic reactions
• Encourage increase fluid intake, take on empty
  stomach

29
Antimycobacterials

• Used to treat or prevent TB infection
• Used in caution with liver disease or severe
  renal impairment
• AE hepatitis, peripheral neuropathy
• Review diet and alcohol restrictions

30
Antiviral

• Acyclovir
• Treats herpes-viruses herpes simplex, herpes
  zoster, Epstein Barr virus, CMV
• Effective against actively replicating viruses
• AE N/V, anorexia, nephrotoxic

31
Antifungal

• Amphotercin (Fungizone)
• Wide spectrum of activity against many fungi
• Can cause anemia, hypokalemia, hypomagnesemia.
• AE nephrotoxicity