1. Introduction to Antimicrobial Drugs*
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Introduction to Antimicrobial Drugs
Drugs used to fight infection are called either antimicrobials or anti-infectives. What was the first effective antimicrobial?
Penicillin. We know that with the advent of these drugs morbidity and mortality have been greatly reduced. *

2. Classification by Susceptible Organism*
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Classification by Susceptible Organism
Antibacterial
Antiviral
Antifungal
Antiprotozoan
Anthelmintic
We usually classify them according to the organism they are effective against or by their mechanism of action. Antibacterial drugs are classified according their spectrum of activity. Such as narrow spectrum are effective against a few types of bacteria whereas wide spectrum has a wider range of bacteria. Antheminitic-worms *

3. Mechanism Of Action Inhibition of bacterial cell wall synthesis*
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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
Antimicrobals all work in different ways. In addition antibiotics may be classified as Bacteriocidal- kills bacteria or bacteriostatic inhibit bacteria, but doesn’t actually kill them. it can be reversible unless the host itself has destroyed the organism.
Sulfonomides, erythromycin and tetracyclines are examples of bacteriostatic drugs. Penicillins and the cephalosporins weaken the cell wall bybinding with certain proteins to to decrese synthesis of the cell wall. These antibiotics are also called autolytic in that they also destroy the cell wall by destroying such as with vancomycin. Inhibition of protein synthesis: there are drugs that are able to disrupt bacterial protein synthesis9ribosomes0. examples are erthromycin and clindamycin. Inhibition of nucleic acid synthesis inhibit DNa synthesis that is used for bacterial repliation such as the fluorquinolones. Inhibition of metabolic pathways(antimetabolites). Nucleic acid synthesis is dependent on folic acid for productionthere are certin drugs that prevent this process from occurringsuch as the sulfonomides. Destruc of cell membrane permeability: the antifungal drugs acta to alter the cell wall permeabilitythey act as inhibitors of enzymes involved in the synthesis of sterols which are essential components of the fungalsmembranes.
Lastly, we have inhibition of viral enzymesthese drugs inhibit essential enzymes for replication. Acyclovir is an example of this type of drug *

4. Direct Exam Of Tissue & Secretions*
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Direct Exam Of Tissue & Secretions
Gram stain
Morphology
Use of special reagents, stains
Cultures
Common organisms and identification
From your studies in Microbiology you understand that it is important ti identify the pathogenHow do we do this? By the gram stain which is the gold standard. If the pt is pretreated before the organism is identified it will be more difficult. What does the gram stain identify ( + & -) Gram pos- aeorbic, ( staph, strep) gram neg- anaerobic( E-colikleibsiella, pseudomonas, gram-neg (gonorrhea)no oxygen required. *

5. Diagnosis Of Infection*
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Diagnosis Of Infection
Signs and symptoms
fever, increased WBC, pain, inflammation, erythema
Microscopic exam of fluids
CSF, urine, blood
Identification of organism
culture, sensitivity
What is the normal WBC count( 5-10,000) *

6. *
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Empiric Therapy
The antibiotic selected is one that can best kill the microorganisms known to be the most common cause of infection
Remember organism should be culutres to find right organism. Culture and sensitivity test. Sometimes can be drug resistant. Culutre determines what bug while the sensitivity determines the drug. Narrow spectrum: treat limited oragnisms-have Identified organisms- less likely to disrupt normal flora. Broad-spectrum treat multiple organisms- more likelt to dusrupt normal flora.. Used when a specific causative organism is unknown. *

7. Empiric Therapy Selection*
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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
Narrow spectrum drug treats limited organisms while the broad spectrum treats a greater array of organisms. However the broader spectrum drugs can disrupt the normal flora, while the narrow spectrum has less of an effect. *

8. *
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Prophylactic Therapy
The antibiotic given when there is likelihood of microorganisms being present and used to PREVENT infection
Pt may be scheduled to have a procedure when there is a likelihood of organisms being present. Surgical procedure. Give Ampicillin or clindimyacin for Group-Beta strep in pregnant women in labor. *

9. Antimicrobial Resistance*
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Antimicrobial Resistance
Production Of Drug-inactivating Enzymes
Mrsa
Vre Tb
What is antimicrobial resistance? The microbe becomes resistant to the drug. Specifically, the the beta-lactam antibiotics are affected by the microbes ability to produce the beta-lactamase enyzymes which can inactivate the particular drug.. Many of these have developed enzymes to inactivate the effects of penicilli Stap aureus is almost entirely penicilln resistant. MRSA- methicillin-resistant Staphylococcus aureus- in MRSA this pathogen is widely resistant to to almost al the penicillins so that there is an alteration of penicillin binding proteins which resuces the ability of penicillins to inhibit cell wall synthesis. Many strains of Msra is also resistant to the aminogycosides, tetracyclines.
Vancomycin-resistant enterococci (VRE)- Strins of enterococci have developed resistance to penicillin, gentamicin and vancomycin. Other antibiotics such as Cipro have been used un their placem. Tb has also become multiple-drug resistant. The cause of this multiple resistance is inadequate drug therapy. It may be too short of a time on drug or a dose that was too low or may have been related to compliance. *

10. General Considerations*
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General Considerations
ID of the pathogen
Drug susceptibility
Drug spectrum
Drug dose
Period of time to affect the pathogen
Site of infection
Patient assessment
The most important consideration is to match the right bug with the right drug. Treat viral agents with antivirals treat bacterial agents with antibacterial drugs. Clearly identify pathogen with gram-stain, Do a C&S to determine the best drug for the pathogen. . Also important to choose a drug with the lowest effective dose to affectThe organism, no growth is seen.the MIC- minimum inhibitory concentration.
Drug Susceptibility In choosing the best drug it might be necessary to do a C&S, however the site of the infection often gives valuable info on the the most effective drug.ie, urinary tract infec caused by Ecoli. That is called”empiric Therapy’’ If the infection, however may be caused by multiple bacteria. A C& S would be necessary? When would A C&S be performed? Drug Spectrum-narrow or wide Choose the drug with the narrowest spectrum. Prevents suprainfections p938. Sometimes combination therapy may be used . When multiple drugs are used the microbe is less likely to become drug resisitant..
Drug Dose- Amt of drug needed to choose the lowest effective response.
Period of Time-Also important to that takes the shortest period of time to affect the organism. Averagetime 7-10 days, dependent on organism.
Site of Infection: TO be effective must reach the site with a concentration greater than the MIC. With abcess and pus formation concentration drugs will be impeded, decreased vasculants
Pt Assessment: Each pt must be carefully evaluated prior to initiating antibiotic therapy , What is their overall health status, other meds, drug allergies, gender, culture. Also remember that the pt’s immune system is a critical factor in determining is very important. For example immunocompromised pts should receive bacteriostatic drugs because their immune response is limited.
Remember age is another critical factor- usually the elderly as well as infants are most prone to drug toxicity *

11. Agent Classification Narrow-spectrum: Extended-spectrum:*
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Agent Classification
Narrow-spectrum:
Causative agent known through culture
Extended-spectrum:
Specific causative agent not known
with normal less likely to disrupt normal flora. Extended- treat multiple organisms more likely to disrupt normal flora. *

12. General Side Effects Hypersensitivity*
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General Side Effects
Hypersensitivity
Toxicity to various organs: kidney, liver, skin, bone marrow
Suprainfection
Remember with suprainfection normal flora is destroyed. Can have unrestrained growth that oocurs when normal flora is altered because of treatment with antibiotics. *

13. General Nursing Implications*
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General Nursing Implications
Assess results of C&S 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
Some antibiotics can decrease the effectiveness of birth control pills so it is important to determine this aspect. It is also important to monitor blood levels . Peak Levels –time of maximum effect. A peak level is drawn 30 min to 45 after IV and 1 hr after administration. You want to keep the drug at a therapuetic level p939
Trough Level: Level prior to the next dose *

14. Continued: MONITOR CBC (WBC and differential)*
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Continued:
MONITOR CBC (WBC and differential)
If severe diarrhea, instruct client to drink buttermilk/yogurt to replace flora
Know difference:
Bacteriostatic
Bactericidal
It is especially important for those pts who are on long-term therapyor high dose antimicrobial therapy. Bacteriocidal kills bacteria whereas bacteriostatic inhibits growth. And relies on the immune system to do its work. *

15. Nursing Process Assessment Nursing Diagnosis Planning Intervention*
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Nursing Process
Assessment
Nursing Diagnosis
Planning
Intervention
Evaluation
Assessment See notes on pg 4&5 What are some important pieces of info that we need to gather form the patient?
How about potential nursing dx? Planning phase: Important goals to set? Interventions *

16. Antibiotics Affecting The Bacterial Cell Wall*
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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
Remember that the bacterial cell wall is rigidand it therfore protects the environment ot the cell, anything to disrupt this wall can cause death of the cell.Drugs that affect the cell wall must be able to penetrate the cytoplasmic membrane within the cell
Beta-lactamases are enzymes that disrupt the beta-lactum ring. Penicillins are called beta-lactam antibiotics because their chemical structure contain abeta-lactumring that is essential for antibacterial activity. *

17. Major Side Effects Most common SE are GI*
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Major Side Effects
Most common SE are GI
Rash on abdomen, scalp, or arms…usually 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*
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Combination Products
Clavulanic acid, tazobactam, sulbactam
Bind to enzyme’s active site and allow antibiotic to reach target site
Augmentin,Unasyn
The combination drugs are bound with other beta-lactum antibiotics to act as competitive suicide inhibitors of bacteria’s beta-lactamases. They bind with the enzyme and allow the antibotic to reach its target site.
Augmentum-amoxicillin clavulnic acid. Ampicillin sulbactum =unasyn *

19. Cephalosporins Introduced in 1960’s*
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Cephalosporins
Introduced in 1960’s
Similar to penicillins, bactericidal
4 generations of drug, each with different spectrum
If allergic to penicillins, may be allergic to cephalosporins (1-18%)
Very popular are becoming resistant. Cefazolin (Ancef,Kefzol) is a first generation drug. *

20. Cephalosporins 1st generation 2nd generation Gram + Skin infections*
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Cephalosporins
1st generation
Gram +
Skin infections
take with food to decrease GI upset
2nd generation
gram + and gram -
low cost
broad range of organisms
The second generation have a broader range of organisms that it is effective against. Less sensitive to the beta-lactamases destroying activity(cefaclor, *

21. Cephalosporins 3rd generation 4th generation Works best against Gram -*
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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)
The third generastion are highly resistant to beta-lactamase activity.ceftizoxime, ceftriazome
Fourth generation is active against both gramt and gram-.It has a broader spectrum that 3rd generation and is affective aginst pseudomonas and enterobacteriaceae. Vancomycin is an example of fourth generation. Vancomycin has very toxic effect so that its use is limited. Used only when others fail, able to eradicate most gram positive bacteria. *

22. Antibiotics Affecting Protein Synthesis*
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Antibiotics Affecting Protein Synthesis
Aminoglycosides
Macrolides
Aminoglycosides—gentamycin, macrolides-characterized by molecules made up of large-ring lactones *

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