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Anti-infective Drugs

Anti-infective Drugs. Jan Bazner-Chandler MSN, CNS, RN, CPNP. Bacteria . Bacteria. Gram-positive bacterium has a thick layer of peptioglycan. Gram-negative bacterium has a thin peptioglycan layer and an outer membrane. Common Bacterial Pathogens. Gram positive Staphylococcus aureus

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Anti-infective Drugs

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  1. 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. 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

  15. 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

  16. 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

  17. 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.

  18. 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

  19. Opportunistic Host • Compromised immune system • Infants • Geriatric population • Cancer • HIV positive – low T-cell count • Burns • Skin breakdown • Client with total knee or hip replacement

  20. 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?

  21. Antibiotics • Sulfonamides • Penicillins • Cephalosporins • Macrolides • Fluoroquinolones • Aminoglycosides • Tetracyclines

  22. 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

  23. 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

  24. Specific Use of Sulfa Drugs • HIV patients with pneumocystis carinii’ • May be givenBactrim or Septra prophylactically.

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

  26. 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

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

  28. Penicillin • Derived from mold fungus

  29. 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)

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

  31. Susceptible Bacteria • Gram-positive organisms • Streptococcus • Enterococcus • Staphylococcus

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

  33. Hives

  34. Anaphylaxis

  35. Combination Penicillin / B-lactamases • Unasyn • Augmentin • Timentin • Zosyn

  36. 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

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

  38. 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

  39. Amoxicillin • Trade name: Amoxil, Trimox, Wymox • Classification: aminopenicillins • Indications: skin infections, otitis media (ear infection), sinusitis, respiratory infections. • Inexpensive in generic form but required frequent dosing (q 8 hours)

  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. Meningitis

  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. Impetigo

  47. 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 in clients undergoing orthopedic procedures

  48. 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

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