The Immune System

1. The Immune System Weeks 7 & 8 Chapters 41,42,43 & 45

2. bacterial infections Chapter 41

3. Bacteria • Bacteria are single-cell organisms that are found everywhere. • Bacteria that cause disease are pathogenic. • Bacteria that do not cause disease are nonpathogenic.

4. Bacterial Cells Differ from Human Cells • Bacteria have cell wall and contain certain enzymes that humans lack • Antibiotics exert selective toxicity on bacterial cells by targeting these unique differences • Bacteria can be killed without major effects on human cells • Limit to this selectivity depending on type of antibiotic and dose

5. Methods of Describing Bacteria • Staining characteristics • Gram-positive • Gram-negative • Basic shapes • Bacilli - rod shape • Cocci - spherical shape • Spirilla - spiral shape • Ability to use oxygen • Aerobic - with O2 • Anaerobic - without O2

6. Morphology of Bacteria

7. Morphology of Bacteria • Gram stain contains two dyes: • Crystal violet (blue) • Safranin (red) • Gram positive remains blue/purple. • Gram negative remains red. • Antibiotic susceptibility: • Finding the antibiotic to which the bacteria are susceptible • Disk test and serial dilution

8. Chemotherapy • Chemotherapy: • Use of drugs to kill or stop the growth of cancerous cells or infectious organisms • Bactericidal: • Kills bacteria • Bacteriostatic: • Inhibits reproduction of bacteria • Antibiotic: • Chemical substance obtained from microganisms

9. Acquired Resistance • Mutated bacteria begin to multiply and infect • Patient soon develops infection resistant to conventional drug therapy • This phenonenon is called acquired resistance • Bacteria may pass the resistant gene to other bacteria by transferring small pieces of circular DNA called plasmids

10. Acquired Resistance which leads to superinfections (i.e. MRSA) • 3 primary factors that lead to the development of acquired resistance • Overuse of antibiotics- used in the population for longer time, prescribed more often = higher % if resistant strains • Misuse of antibiotics – patients don’t finish the prescription (must take full length of therapy even if symptoms resolve) • Unwarranted use of antibiotics -prescribed when not necessary

11. Selection of the Correct Antibiotic Is Essential • Broad-spectrum antibiotics - effective against a wide variety of bacteria • Narrow-spectrum antibiotics - effective against only one microorganism or a restricted group of bacteria • Which is better??

12. Culture and Sensitivity • Process of growing isolated organisms and identifying the most effective treatment • Process includes: • Examination of body specimens such as urine, sputum, blood, or pus for microorganisms • Organisms isolated from specimens are then grown in lab so that they may be identified • After identification, lab may test several different antibiotics to determine which is most effective against the identified pathogen

13. Serum levels for antibiotics • Known as Peak and Trough • Typically done on the 3rd dose, and every 3rd dose thereafter • To check to see drugs effectiveness through two serum levels, or lab draws • Trough • Checks to see if there is enough of the drug in the system • This serum level is drawn one hour before the 3rd dose is administered • If too low, the dose may be increased • Peak • Checks to see if there is too much of the drug in the system • This serum level is drawn one hour after 3rd dose has infused • If too high, the dose may be stopped or decreased

14. Secondary Infections • Secondary infections caused by anti-infective therapy • Occur when host flora are destroyed by the antibiotic • Host flora prevent growth of pathogenic microorganisms • Pathogenic microorganisms have a chance to grow and multiply • Signs and symptoms? • Often caused by broad-spectrum antibiotics • Why?

15. Serious Adverse Reactions • Anaphylaxis: • Clinical manifestations/assessment: • Feelings of uneasiness to impending death • Urticaria (hives) and pruritis • Cyanosis and pallor • Congestion and sneezing • Edema of the tongue and larynx with stridor • Bronchospasm, wheezing, and dyspnea • Nausea and vomiting • Diarrhea and involuntary stools • Tachycardia and hypotension • Coronary insufficiency, vascular collapse, dysrhythmias, shock, cardiac arrest, respiratory failure, and death

16. Antibiotic Classes • Pencillins • Beta-lactamase Inhibitors • Cephalosporins • Tetracyclines • Sulfonamides • Macrolides • Fluoroquinolones • Antibacterial/Antiprotozoals • Drugs to treat TB

17. Mechanism of Action

18. Penicillin • Obtained from mold • One of the oldest and safest groups of anti-infectives • Isolated from the fungus Penicillium (1941) • Mechanism of action: • Bactericidal • Disrupts cell-wall synthesis • Splits the cell wall by using a Beta Lactam ring • Classified by spectrum: • Divided into four groups

20. Penicillins • Penicillin G (Pfizerpen) • Amoxicillin (Amoxil) • Ampicillin (Principen) **Generic names all end in cillin NC: may reduce effectiveness of birth control, use back up birth control

21. Penicillinase - Enzyme Secreted by Some Bacteria • Also called beta-lactamase • Splits beta-lactam ring of penicillin • This structural change allows bacteria to become resistant to most penicillin • The penicillin will no longer be effective at killing this type of bacteria

22. Penicillin • Beta-lactamase inhibitors: • Penicillinase—enzyme that stops penicillin from working • MOA: Inhibitors—given with penicillin antibiotics to stop the enzyme activity and allow the penicillin to work more effectively • Augmentin—clavulanic acid and amoxicillin

23. Cephalosporins • Mechanism of action: • Bactericidal • Disrupts cell-wall synthesis • by using a beta lactam ring • Classified by spectrum: • Four separate groups, generations • Generations become stronger and more narrow in spectrum • Substituted for penicillin when allergy or resistance is suspected • Used in treatment of gram-negative infections and for patients who cannot tolerance of less expensive PCNS

24. Cephalosporins • Adverse effects: • GI disturbances • Nephrotoxicity –monitor BUN/Cr • disulfiram (Antibuse) • reaction with alcohol • Allergy—lower than with penicillin • NC: Cross Allergy with Penicillins • Usually not administered to patients who have had an anaphylactic reaction or hives from penicillin

25. Cephalosporins “ceph/Cef-” • First Generation • cephazolin (Keflex) • Second Generation • cefaclor (Ceclor) • Third Generation • ceftriaxone (Rocephin) • Fourth Generation • cefepime (Maxipime)

26. Tetracyclines • MOA: • Broad-spectrum antibiotics • Bacteriostatic: • Interfere with protein synthesis • Used for both gram-positive and gram-negative bacteria: • Indicated for the treatment of ACNE, Rocky Mountain spotted fever, cholera, urethritis, and Lyme disease • Profile Drugs (end –cycline) • tigecycline (Tygacil)—used for MRSA • doxycycline (Vibramycin) • tetracycline (Sumycin)

27. Tetracyclines • Calcium, antacids, and mineral supplements inhibit absorption. • Adverse effects: • Nausea and vomiting, diarrhea, fungal superinfections, mottling of bones and teeth, and photosensitivity • Cautions and contraindications: • Bind to calcium and are deposited in growing bones and teeth—mottling (yellow – brown teeth discoloration) and stunted growth

28. Sulfonamides • Sulfamethoxazole-trimethoprim (SMZ/TMP) • Septra or Bactrim • MOA of Sulfas: • Bacteriostatic • Block synthesis of folic acid • MOA of Trimethoprim • increases the effect of stopping folic acid synthesis, increasing effectiveness of the antibiotic • USE: • for respiratory, urinary, GI, ear, sinus, and pneumonial infections; Today use limited to topical burn creams and treatment of urinary and GI tract infections • Indicated for a broad spectrum of gram-positive and gram-negative bacteria

29. Sulfonamides • Adverse effects: • Nausea, vomiting, and diarrhea • Crystalluria—dehydration and acidic urine • Allergic reactions—rash and photosensitivity • Stevens-Johnson syndrome

30. Macrolide Antibiotics • MOA: Bacteriostatic—inhibit protein synthesis • USE: • Treatment of Legionnaire’s disease and genital infections caused by C. trachomatis • Useful in ear and respiratory infections • Profile Drugs: “-omycin” • azithromycin (Zithromax, Z-pack) • erythromycin (E-mycin) • clarithromycin (Biaxin)

31. Macrolide SE/NC • SE: • Mild GI upset, diarrhea, abd pain • Superinfections • NC: • Zithromax has a long half life, so it can be given over 4-5 days but stay in the system for 10 days • Increases patient compliance

32. Fluoroquinolone Antimicrobials • MOA: • Synthetic antimicrobials • Broad-spectrum • Gram negative • Well absorbed • Bactericidal • Inhibits bacteria’s ability to replicate • Useful in treatment of urinary, respiratory, bone, soft tissue infections, Clostridium Difficile, and anthrax • Ciprofloxin (Cipro)

33. Fluoroquinolone Antimicrobials • Adverse effects: • Headache • Dizziness • GI disturbances • Photosensitivity • Nursing Condsiderations: • Not recommended for children or pregnant women: • Evidence of cartilage defects, tendonitis, and joint pain • Pregnancy Category C

34. Miscellaneous Antimicrobials • clindamycin (Cleocin): • MOA: • Bacteriostatic—inhibits protein synthesis • Effective against gram-positive and anaerobic organisms • Adverse effects—diarrhea • metronidazole (Flagyl): • MOA: • Bactericidal—bacteria and protozoa • Effective against anaerobic bacteria • Adverse effects—GI disturbances, metallic taste, disulfiram reaction with alcohol • Used to treat amebia in the intestines (protozoa-giardia), dysentery, and trichomonas in the vagina

35. Drugs Used to Treat Tuberculosis • Tuberculosis: • Infection caused by M. tuberculosis • Usually affects the lungs, but can spread to other body areas • Immune response isolates pathogens in tubercles • Increase in bacterial resistance to drug therapy • Cell wall is resistant to penetration by anti-infective drugs • Combination therapy—best approach

36. Drugs Used to Treat Tuberculosis • Isoniazid (INH): • MOA: • Bactericidal • Inhibits cell-wall synthesis • Adverse effects—peripheral neuritis and hepatotoxicity • NC: no ETOH, monitor LFTs and monitor for jaundice, give Vit B6 to prevent nerve damage • Rifampin: • MOA: • Wider antibacterial spectrum than isoniazid • Inhibits enzyme required for RNA • Adverse effects—GI disturbances, hepatotoxicity, rash, headache, and turns urine red-orange

37. Long-Term Therapy - 6 to 12 Months • To reach isolated microorganisms in the tubercles • Must continue therapy even if not infectious or have no symptoms the entire time • Some clients develop multidrug-resistant infections • Require therapy for 24 months

38. Chemoprophylaxis • Antituberculosis drugs used to prevent the disease • Close contacts and/or family members of recently infected tuberculosis client • Therapy begins immediately after client has a positive tuberculin test • Clients with AIDS, HIV-positive, or receiving immunosuppressants

39. Question ONE • The client taking isoniazid (INH) reports paresthesia of the extremities. The nurse initially monitors the client for which of the following? • 1. Hyperactive motor reflex responses • 2. Other clinical manifestations of hypercalcemia • 3. Concurrent self-administration of aluminum antacids • 4. Compliance with taking pyridoxine (vitamin B6) supplement

40. Question Two • What teaching or intervention is appropriate for a client taking an antibiotic that causes diarrhea secondary to elimination of normal intestinal flora? • 1. Test stool for occult blood • 2. Include yogurt or buttermilk products in the diet • 3. Arrange for IV administration instead of oral route • 4. Take antacids with antibiotic to reduce diarrhea

41. Question Three • A patient is prescribed penicillins concurrently with oral contraceptives. What does the nurse tell the patient to do? • A. Discontinue oral contraceptives during infection • B. Obtain a penicillin prescription for his or her partner • C. Remain on oral contraceptives and use an additional form of birth control • D. Take each drug 1 to 2 hours apart

42. Antifungal and antiviral medications Chapter 42

43. Fungal Infections • Fungi are found in soil, air, and contaminated food. • Mycoses are infections or diseases caused by a fungus. • Infections can be of three types: • Systemic—throughout the body • Dermatophytic—hair, skin, and nails • Candida albicans—skin, mucous membranes

44. Fungal Infections • Systemic: systemic mycoses • Infect blood, bones, and lungs • Can be dangerous in chronically ill patients • Becoming more common in hospitals: • Neutropenic patients • Immunocompromised by HIV • Patients in intensive care for extended periods

45. Fungal Infections • Dermatophytic: superficial mycoses • Infect hair, nails, and skin • Most common type of fungal infection • More annoying than serious • Symptoms—itching, discolored and scaling skin, inflammation, blisters, and broken skin • Caused byTineaspecies

46. Common Superficial Mycoses Infections • Tineapedis (athlete’s foot) • Tineacruris (jock itch) • Tineacorporis (ringworm)

47. Fungal Infections • Candida albicans: • Vaginal yeast infections—moniliasis • Can also thrive in: • Mouth • Pharynx • Esophagus • GI tract • Urinary bladder • Thrush—a candida infection of the mouth or pharynx

48. Antifungal Drugs • Have no antibacterial or antiviral activity • Affect only certain pathogenic fungi • Fungicidal • Change cell-wall permeability or affect cell-wall synthesis • Classes: • Systemic Antifungals: Azoles • Superficial Antifungals: Nystatin

49. Systemic Antifungal Drugs (MOA) • Azoles: • Ketoconazole (Nixoral), fluconazole (Diflucan), itraconazole (Sporanox) • USE: Wide spectrum of activity against common fungal pathogens • Adverse effects: • Fever • Rash • Nausea, vomiting, diarrhea • Headache • Hallucinations • Hepatotoxicity (NC: Monitor LFTs)

50. Antifungal Drugs • Azoles: • USES: (common fungal pathogens…) • Used for cryptococcal and coccidioidal meningitis • Also used for candidiasis infections • Used to treat several types of fungal infections: • Histoplasmosis, paracoccidioidomycosis, blastomycosis, • Invasive aspergillosis, fungal meningitis • NC: Absorption increased with food