1. Jan Bazner-Chandler MSN, CNS, RN, CPNP
Anti-infective Drugs
Jan Bazner-Chandler
MSN, CNS, RN, CPNP

2. Bacteria

3. Bacteria Gram-positive bacterium has a thick layer of peptioglycan.
Gram-negative bacterium has a thin peptioglycan layer and an outer membrane.

4. Common Bacterial Pathogens
Gram positive
Staphylococcus aureus
Streptocci
Enterococci
Gram negative
Escherichia coli or E-coli
Klebsiella
Proteus
Pseudomonas

5. Empiric Therapy
Administration of antibiotics based on the practitioner’s judgment of the pathogens most likely to be causing the infection; it involves the presumptive treatment of an infection to avoid treatment delay before specific cuture information has been obtained.

6. Prophylactic Antibiotic Therapy
Antibiotics taken before anticipated exposure to an infectious organism in an effort to prevent the development of infection.
IV antibiotics given prior to surgery

7. Superinfection
An infection occurring during antimicrobial treatment for another infection, resulting from overgrowth of an organism not susceptible to the antibiotic used.
A secondary infection that occurs due weakening of the patients immune system by the first infection.

8. Examples of Superinfections
Fungal or yeast infection
Diarrhea due to diminished normal flora of the gastrointestinal tract.

9. Laboratory Tests Gram stain – microscopic identification of organism
Culture – identifies causative agent and susceptibility to specific antibiotics
Serology – titers or antibodies measured
CBC – looking at WBC

10. Cultures
Throat
Wound
Urine
Sputum
Blood

11. Clinical Pearl
Always collect culture: urine, sputum, wound drainage, or blood prior to starting antibiotic therapy.
If technician is drawing blood make sure it has been done before starting antibiotics.

12. Antimicrobials
Drugs used to prevent or treat infection caused by pathogens

13. Two Classifications Bactericidal drugs kill bacteria directly.
Bacteriostatic drugs prevent bacteria from dividing or inhibits their growth.

14. Infectious Disease
Infections disease involves the presence of pathogen plus clinical signs and symptoms indicating infection.
Microorganisms spread by direct contact with infected person or contaminated hands, food, water, or objects.

15. Opportunistic Infections
Severe burns
Cancer
HIV
Indwelling IV catheter or urinary catheter
Corticosteroid therapy
Fungal or viral infections

16. Two Types of Bacteria Aerobic – grow and live in presence of oxygen
Staph & Strep
Anaerobic – cannot grow in presence of oxygen
Deep wounds
Characterized by abscess formation, foul-smelling pus and tissue destruction

17. Community-Acquired Infection
Less severe and easier to treat, although drug resistant strains are increasing
Remember Staph is everywhere – it is normal flora on skin and in the upper respiratory tract
MRSA: methicillin-resistant-Staphylococcus aureus

18. Nosocomial Infections
More severe and difficult to manage because they often result from drug-resistant microorganisms and occur in clients whose resistance is impaired
Pseudomonas
Proteus

19. Bacterial Resistance
Bacteria develop the ability to produce substances which block the action of antibiotics or change their target or ability to penetrate the cells.

20. What causes resistance?
Widespread use of antimicrobial drug
Interrupted or inadequate antimicrobial treatment of infection
Type of bacteria – gram-negative strains have higher rates of resistance
Re-occurring infections
Condition of the host
Location – critical care areas

21. Client History / Assessment
Allergies
Previous drug reactions
Baseline renal and liver function
Review culture reports for appropriate antibacterial drug choice
Patient response to antibiotics therapy
Are they getting better?
Any side effects?

22. Antibiotics Sulfonamides Penicillins Cephalosporins Macrolides
Fluoroquinolones
Aminoglycosides
Tetracyclines

23. Sulfonamides
Action: inhibit the growth of bacteria (bacteriostatic antibiotic) by inhibiting the growth of susceptible bacteria by preventing bacterial synthesis of folic acid.
Usually used in combination drugs.
Trimethoprim / sulfamethoxazole: Trade name Bactrim, Septra, TMP/SMX

24. Indications
Broad spectrum: can be used against gram negative and gram positive organisms
Very useful in treating kidney infections since they achieve a high concentration in the kidneys.
Susceptible organisms: Enterobacter, E.Coli, Klebsiella, Proteus
Problem: organisms becoming more resistant

25. Specific Use of Sulfa Drugs
HIV patients with pneumocystis carinii’
May be given Bactrim or Septra prophylactically.

26. Contraindications Drug allergy to sulfa
Use of thiazide and loop diuretics
Pregnant women
Infants younger than 2 months of age

27. Adverse Effects
Most common is cutaneous reactions – can occur weeks after therapy started.
Erythema multiforme (Stevens Johnson Syndrome)
Toxic epidermal necrolysis
Photosensitivity reactions: exposure to sunlight can result in severe sunburn

30. B-Lactam Antibiotics Includes 4 major drug classifications penicillins
cephalosporins
carbapenes
monobactams

31. Penicillin
Derived from mold fungus

32. Penicillin First generation IM or IV
Newer penicillins have been developed that increase gastric acid stability of penicillin
Good drug since it enters most bodily fluids: joint, pleural, and pericardial.
Not effective against intraocular (eye) or cerebral spinal fluid infection (CSF)

33. Penicillin Bactericidal action against sensitive bacteria
Action: binds to bacterial wall, resulting in cell death

34. Susceptible Bacteria Gram-positive organisms Streptococcus
Enterococcus
Staphylococcus

35. Adverse Reactions
Most common reaction is GI (diarrhea) when administered orally.
Urticaria, pruritus, and angioedema
Severe reaction: Steven’s Johns Syndrome
Note: when giving IV or IM observe for ½ to 1 hour after giving for adverse reactions.

36. Combination Penicillin / B-lactamases
Unasyn
Augmentin
Timentin
Zosyn

37. Ampicillin – Synthetic Penicillin
Broad spectrum effective against several gram-positive and gram-negative bacteria
E-coli, proteus, Salmonella, Shigella
Not effective against staphylococci on gonococci
Bronchitis, sinusitis, and otitis media

38. Ampicillin Bactericidal action – spectrum is broader than penicillin
Binds to bacterial wall resulting in cell death

39. Nursing Implications Same as penicillin
Ask client about oral contraceptive use – drug may cause transient decrease in effectiveness
Advise to use additional BC – barrier protection during antibiotic therapy

40. Amoxicillin Oral equivalent of Ampicillin
Readily absorbed and reaches therapeutic levels rapidly
Drug of choice in prevention of bacterial endocarditis
Clients with total knee or hip replacement, heart valve replacement need to take prior to any dental work, endoscopy exams

41. Dosing for Amoxicillin
Adults: 250 to 500 mg q8h
Infants and children less than 20 kg:
20 – 40 mg / kg / day divided into doses q 8 hours

42. Cephalosporins Widely used drug derived from fungus
Used against gram–negative bacteria
Widely absorbed and distributed in most bodily fluids – placenta and breast milk

43. Cephalosporin
First generation Cephalosporin drugs do not reach therapeutic levels in CSF (cerebral spinal fluid) but 2nd, and 3rd generation drugs do – especially important in treating meningitis

44. First Generation Cephalosporins
Bactericidal action – binds to bacterial cell wall, causing cell death
Keflex (PO) still used extensively in treatment of skin infections
Ancef – often ordered preoperatively

45. First Generation Cephalosporins
Bactericidal action – binds to bacterial cell wall, causing cell death
Keflex (PO) still used extensively in treatment of skin infections
Ancef – often ordered preoperatively

46. Keflex First generation cephalosporin
Action: binds to bacterial cell wall membrane, causing cell death
Therapeutic effect: bactericidal action against susceptible bacteria
Active against many gram-positive cocci – step and staph

47. Client teaching
May be taken with or without food but food may minimize the GI irritation
Distribution: may cross placenta or enter breast milk in low concentrations.
Excreted entirely by the kidneys.

48. Keflex Dosing Adults: 250 – 500 mg q 6 hours
Children: 25 – 50 mg / kg / day in divided doses q 6 h

49. Cefazolin or Ancef Cefazolin – first generation cephalosporin
Well absorbed following IM or IV administration
Crosses to placenta and breast milk in small concentrations
Minimal CSF penetration
Excreted by kidneys

50. Ancef Dosing IV Used for UTI, bone and skin infections, endocarditis
Not suitable for treatment of meningitis
Perioperative prophylaxis
1 gram within 60 minutes of incision
Post operatively every 8 hours for 24 hours (3 doses)

51. Second-Generation Cephalosporins
More active against some gram-negative organisms and anaerobic organisms than the first generation drugs.
May be effective in infections resistant to other antibiotics
Penetration into CSF is poor but adequate to be used in meningitis
Action: bactericidal – binds to cell wall

52. Third Generation Cephalosporin Drugs
Similar to the second generation but has increased activity against gram-negative pathogens even for drug resistant pathogens.
CSF penetration is better than the first two generation cephalosporin drugs.

53. Drug / Drug Allergies
If a client is allergic to penicillin there is a 1 to 18% chance they will be allergic to cephalosporin drugs.

54. Carbapenems Has very broad antibacterial action
Are often used for complicated body cavity and connective tissue infections in the hospitalized patient.
imipenem-cilastatin (Primaxin)
meropenen (Merrem): only drug in this class used in the treatment of bacterial meningitis.

55. Macrolides
Macrolides first developed in the 1950s with the drug: erythromycin.
Four main drugs
azithromycin * Zithromax
Clarithromcin * Biazin
dirithromycin
erythromycin

56. Macrolides
Two of the new drugs in the macrolide classification: azithromycin and clarithromycin have longer duration and improved resistance to acid degradation in the stomach.
Dosing is less frequent
GI effects decreased
Better absorption than erythromycin

57. Macrolides
Action: work by inhibiting protein synthesis in susceptible bacteria.
Contraindications: drug allergy
Adverse effect: two new drugs have lower GI effects and are used in patients allergic to penicillin / cephalosporin drugs.

58. Ketaloids Only one drug in this drug classification
Generic: telithromycin
Trade: Ketek
Available for oral use only.
Better acid stability and antibacterial coverage than macrolides.

59. Tetracyclines
Action: binds to divalent (Ca2 + mg2) and Al3 mettalic ions to form insoluble complexes.
Why do you need to know this?
When given with milk, antacids or iron there is a reduction in oral absorption.
Contraindicated in children under 8 years of age because it can result in tooth discoloration.

60. Tetracyclines
When used? Syphilis and Lyme disease

61. Antibiotics Used to Treat Serious Infections
IM or IV administration
Have more toxic side effects
Blood levels may need to be monitored to determine therapeutic versus toxic levels of mediation in the blood.

62. Serious Adverse Effects
Nephrotoxicity: Toxicity to kidneys, often drug induced and manifesting in compromised kidney function.
Ototoxicity: Toxicity to the ears, often drug-induced and manifested by varying degrees of hearing loss than is likely to be permanent.
Pseudomembranous colitis: a necrotizing, inflammatory bowel condition associated with antibiotic therapy.

63. Aminoglycosides Pharmacologic classification: Bactericidal drugs
Therapeutic classification: anti-infective
Action: inhibits protein synthesis at the level of the 30s ribosome
Work primarily on dosing due to concentration dependent killing of bacteria

64. Concentration Dependent
A property of some antibiotics, especially aminoglycosides and vancomycin, of achieving a relatively, high plasma drug concentration, results in the most effective bacterial kill.

65. Blood Plasma Levels
Peak levels: refers to amount of drug present in blood plasma within
15 to 30 minutes of IV drug administration
30 to 90 minutes of IM drug administration
Trough levels: refers to lowest level of drug present in the blood plasma.
Since the drugs can cause severe adverse effects the excretion of the drug needs to be monitored.
Blood drawn just before the next dose given.

66. Adverse Effects Aminoglycosides
Nephrotoxicity occurs in 5 to 25% and ototoxicity (damage to VIII cranial nerve) occurs in 3 to 14%.

67. Aminoglycosides gentamicin (Garamycin) tobramycin (Nobcin, TOBI)
neomycin (Neo-Fradin)
used to irrigate bowel before major bowel surgery
Topical applied to eye and skin infections

68. Floroquinolones Action: destroys bacteria by altering their DNA.
Two most common drugs:
ciproflxcin (Cipro)
clindamycin (Cleocin)
Used in treatment of chronic infections or deep (anaerobic) abdominal infections and MRSA.

69. Major Adverse Side Effect
Clindamycin or Cleocin can cause pseudomembranous colitis
Signs and symptoms: abdominal pain and diarrhea

70. MRSA Infections
MRSA infection is caused by Staphylococcus aureus bacteria — often called "staph." MRSA stands for methicillin-resistant Staphylococcus aureus. It's a strain of staph that's resistant to the broad-spectrum antibiotics commonly used to treat it. MRSA can be fatal.

71. Vancomycin
Action: destroys bacteria by binding to the bacterial cell wall, producing immediate inhibition of cell wall synthesis and death.
Most common drug used in MRSA infections.

72. Adverse Effect
Red man syndrome has often been associated with rapid infusion of the first dose of the drug and was initially attributed to impurities found in vancomycin preparations. Even after improvement in vancomycin's purity, however, reports of the syndrome persist.
Flushing on upper chest, neck and face
Intervention: slow the infusion rate.

73. Anti-viral Drugs
Kill or suppress viruses by either destroying virons or inhibiting their ability to replicate.
Does not irradiate the virus but helps the immune system to eliminate the virus.

74. Drugs to help with the Flu
Tamiflu and Relenza
Uses: active against influenza virus types A and B.
Shown to reduce the duration of influenza infection by a few days.

75. Herpes Zoster Herpes simplex virus type 1: cold sore
Herpes simplex virus type 2: genital herpes
Human herpesvirus type 3: chicken pox or shingles
Human herpesvirus type 4: Espstein Barr Virus
Human herpesvirus type 5: CMV or cytomegalovirus

76. Herpes Drugs Generic: acyclovir Trade: Zovirax
Action: interferes with DNA synthesis.
Therapeutic effects: Inhibition of viral replication, decreased viral shedding and reduced time for healing of lesions.

77. acyclovir Comes in topical, po and IV preparations
Should be started within 24 hours of outbreak.