Chapter 34- Antibiotics Flashcards
Compare and contrast the terms pathogenicity and virulence
Pathogenicity-the ability of an organism to cause infection
Virulence-measure of disease…the producing potential
-highly virulent pathogen can cause disease when present in small numbers
Explain how bacteria are described and classified
- SHAPE- rod shapes=bacilli; spherical shapes= cocci; spiral shapes=spirilla
- OXYGEN- aerobic- thrive in an oxygen rich environment; anaerobic- grow best without oxygen
- STAINING- gram positive= thick cell wall&retain purple; gram negative- thinner cell walls&red/pink color
Compare and contrast the terms bacteriostatic and bacteriocidal
Bacteriostatic- do not kill bacteria, but slow their growth, allowing the body’s natural defenses to eliminate the micro organisms
Bacteriocidal- kill the bacteria
Using a specific example, explain how resistance can develop to an anti-infective drug
Bacteria duplicate rapidly. During this duplication, they make frequent errors in the genetic code. These are mutations and can survive in harsher conditions.
Antibiotics kill populations of bacteria that are sensitive to the drug but leave behind the mutated bacterium. This makes this mutated bacteria free to grow and unrestrained by their neighbors that were killed by the antibiotic. The patient then develops an infection that is resistant to conventional drug therapy.
Bacteria can then pass the resistance gene to other bacteria through conjugation.
Describe the nurses role in the pharmacological management of bacterial infections
- monitor clients condition
- provide client education
- obtain medical, surgical, and drug history
- assess lifestyle and dietary habits
- obtain description of symptomology and current therapies
- OBTAIN SPECIMENS FOR CULTURE AND SENSITIVITY PRIOR TO START OF THERAPY
- monitor for indications of response to therapy
- reduced fever, normal WBC, improved appetite, etc. - after PARENTERAL ADMIN., OBSERVE CLOSELY FOR POSSIBLE ALLERGIC REACTIONS
- monitor for SUPERINFECTIONS
- teach clients to WEAR MED-ALERT BRACELETS, REPORT SYMPTOMS, TAKE COMPLETE PRESCRIPTION
Explain importance of culture and sensitivity testing to anti-infective chemotherapy
Laboratory tests should be conducted to identify the specific pathogen PRIOR to beginning anti-infective therapy.
After pathogen is identified, laboratory tests several different antibiotics to determine which is most effective against the infecting microorganism.
BROAD SPECTRUM antibiotics- one that is effective against a wide variety of different microbial species (used when identification may take several weeks and pt. needs to start therapy)
NARROW SPECTRUM- given after lab testing is complete. Effective against a smaller group of microbes or only the isolated species
Multidrug therapy
- Antagonism- combining two drugs may decrease each drugs efficacy
- use of multiple antibiotics has the potential to promote resistance
- multidrug therapy is used when several different organisms are causing patients infection
- multidrug therapy is clearly warranted in the treatment of tuberculosis or in patients infected with HIV
Identify the mechanism of development and symptoms of superinfections caused by anti-infective therapy
- superinfections occur when microorganisms normally present in the body (host flora) are destroyed
- removal of host flora by an antibiotic gives the remaining microorganisms an opportunity to grow, allowing for overgrowth of pathogenic microbes
opportunistic microorganisms
Microbes that become pathogenic when the immune system is suppressed are opportunistic organisms
Signs and symptoms of a superinfection
- diarrhea
- bladder pain
- painful urination
- abnormal vaginal discharge
PENICILLIN mechanism of action and prototype drug
- prototype- penicillin G (pentids)
- most effective against gram positive bacteria
- kill bacteria by WEAKENING CELL WALL and allows water to enter, killing the organism
Beta-lactam ring and associated enzyme
- penicillin has beta-lactam ring which is responsible for antibacterial activity
- some bacteria contain beta-lactamase or penicillinase which SPLITS beta-lactam ring (these bacteria are resistant to penicillin)
Adverse effects of penicillin
- Diarrhea, nausea, vomiting, superinfections, anaphylaxis
- penicillins are one of the SAFEST classes of antibiotics
- ALLERGY is most common adverse effect
- includes rash, pruritis, and fever - if client is allergic to penicillin, avoid cephalosporins
- skin rash; decreased RBC,WBC, or platelet counts
new penicillins are penicillinase resistant…how?
- combination drugs- when combined with a penicillin, these agents protect the penicillin molecule from destruction, extending its spectrum of activity
- less likely to become resistant to certain bacteria
Drug therapy with penicillins
- AVOID CEPHALOSPORINS if client has penicillin allergy
- monitor for hyperkalemia and hypernatremia
- monitor cardiac status, including ECG changes
Penicillin as plain m&ms
- Hard coating (attacks bacterial cell wall)
- been around forever
- chocolate is easy to have allergic reaction to
- but, chocolate is usually well tolerated
- take on an empty stomach (no filling or “food” in the M&MS)
CEPHALOSPORINS mechanism of action and prototype drug
- prototype- cefotaxime (claforan)
- similar in structure and function as penicillins
- cephalosporins act with broad-spectrum activity against gram-negative organisms (primary use is for gram-negative infections and for patients who cannot tolerate the less expensive penicillins)
- CROSS SENSITIVITY WITH PENICILLINS
Cephalosporins adverse effects
- allergic reactions are most common adverse effect
- hypersensitivity, anaphylaxis, diarrhea, vomiting, nausea, pain at injection site
Generations of cephalosporins
- FIRST- most effective against gram-positive organisms
- SECOND- more potent; more resistant to beta lactamase; exhibit broader spectrum against gram-negative organisms
- THIRD- even broader spectrum against gram-negative; longer duration of action and resistant to beta lactamase
- FOURTH- effective against organisms that have developed resistance to earlier cephalosporins; third and fourth are capable of entering CSF to treat CNS infections
Cephalosporin drug therapy
- assess for precense or history of bleeding disorders
- assess renal and hepatic function
- avoid alcohol- SOME CEPHALOSPORINS CAUSE ANTABUSE LIKE REACTION WITH ALCOHOL
