Pharm Lesson 7

Describe in general the difference between cephalosporin generations.

Each newer generation represents a broader spectrum, effective against more forms of bacteria

Explain why Vancomycin should be reserved for only the most severe bacterial infections.

Serious adverse effects such as nephrotoxicity, ototoxicity, and anaphylaxis are associated with Vancomycin.

Broad spectrum refers to:

antibacterial agents which are effective against a wide variety of gram-positive and gram-negative bacteria

Indications for aminoglycosides?

bacterial infections - Deadly gram-negative nosocomial infections such as Klebsiella and Pseudomonas

Indications for macrolides?

bacterial infections - Legionnaire's disease; STDs; UTIs; Pertussis

Indications for Vancomycin?

bacterial infections - Most resistant and severe bacterial infections

Indications for fluoroquinolones?

bacterial infections - Respiratory tract infection; skin infection; MRSA infection

Indications for tetracyclines?

bacterial infections - Rocky Mt spotted fever; Chlamydia; Lyme disease; Anthrax; Cholera

Antifungal mechanism of action?

binding to fungal membranes, increasing cell permeability; vital stuff leaks out of cell

Antiretrovirals mechanism of action?

blocks replication cycle

Define ototoxicity:

toxic to ears/hearing loss

Define nephrotoxicity:

toxic to kidney

Indications for antiprotozoans?

trichomonas

Indications for antituberculars?

tuberculosis

Indications for antihelminthics?

worm infestation

Explain why tuberculosis requires a concurrent multi-antibacterial regimen.

By administering several drugs with varying mechanisms of action, the chance of resistance is lowered; long-term administration of several antibiotics results in more effective penetration of the tubercules (nodules in the lungs)

What is the most serious side effects of penicillins?

anaphylaxis

Define broad-spectrum antibacterial agents (antibiotics):

effective against a wide variety of gram-positive and gram-negative bacteria

Indications for antivirals?

viruses

Identify the advantage of combination antibacterials such as Augmentin and Timentin

It combats resistance.

Explain why antibiotics (antibacterials) are ineffective against viruses.

Viruses have no cell wall that can be breached; they do not reproduce in the same way that bacteria do; they are not dependent on folic acid. Because of those things and the unique structural and metabolic properties, antibiotics, antifungals, and antiparasitics are ineffective against viruses

Differentiate between a bacteriocidal agent and a bacteriostatic agent.

Bacteriocidal - an agent that is capable of killing bacteria bacteriostatic - an agent that inhibits (stops) the bacteria's ability to reproduce

Explain how culture and sensitivity studies should be used in determining appropriate antibiotic therapy.

First step in treatment is to culture the specimen to determine type and strain of organisms causing infection. Then, a sensitivity study is done to fine out which antibiotic agents will stop the infection. While this is being done, broad-spectrum antibiotics will be started which are effective against a variety of gram-positive and gram-negative bacteria. When the culture and sensitivity results are in, a narrow-spectrum antibiotic can then be selected based on those results.

Explain the role of the beta-lactam ring and B-L ring enzyme (beta-lactamase) in antibiotic choice and bacterial resistance.

Penicillin cells have a ring around it called the beta-lactam ring. Some bacteria have an enzyme called beta-lactamase which can break down this ring making the penicillin ineffective. This is one of the causes of antibiotic-resistant bacteria. To combat this problem, extended spectrum penicillins are produced that combine an antibiotic with a drug that inhibits production of beta-lactamase (Augmentin, Timentin, and Zosyn)

Name the side effects associated with Vancomycin and explain precautions that should be taken in patients receiving this drug.

Serious adverse effects such as nephrotoxicity, ototoxicity, and anaphylaxis are associated with Vancomycin; should undergo blood and urine tests 2 to 3 times a day to monitor for signs of adverse reactions.

Some antibacterials inhibit protein synthesis, which in turn inhibits bacterial reproduction. This represents:

a bacteriostatic agent

Cephalosporins are grouped into subcategories called "generations" with each higher generation representing:

a broader spectrum of effectiveness

Define pathogenicity:

ability of a pathogenic agent to produce a disease in any given species

Define chemoprophylaxis:

administration of antibiotics to prevent an infection

Define superinfection:

aka secondary infection/opportunistic infections; UTIs and pulmonary infections; common in compromised patients because their immobility and impaired immunity makes them susceptible to organisms that most of us come into contact with daily

Appropriate medication category for a patient diagnosed with pinworms (a species of roundworm) is:

antihelminthetics

These drugs act by blocking the replication cycle of human immunodeficiency virus (HIV):

antiretrovirals

MRSA is a resistant strain of:

bacteria

Define culture and sensitivity:

culture - determining type and strain of organism sensitivity - finding out which antibiotics will stop the infection

What is the primary use of aminoglycosides?

deadly gram-negative noscomial infections such as Klebsiella and Pseudomonas

Define narrow spectrum antibacterial agents:

effective against very specific types of bacteria

Indications for antifungals?

fungal infections

Define nosocomial infection:

hospital or healthcare facility acquired infection

Antivirals mechanism of action?

impairs viral protein synthesis

Bacteriostatic antibacterials (macrolides, tetracyclines) mechanism of action?

keeps bacterial from multiplying/inhibits its ability to reproduce

Bacteriocidal antibacterials (penicillin) mechanism of action?

kills the bacteria

Which drug category would be indicated for a gram-positive infection in patients who are allergic to penicillin?

macrolides

Indications for antimalarials?

malaria

Define MRSA:

methacillin-resistant Staphylococcus aureus - first antibiotic-resistant bacteria, but many others now exist

Define virulence:

power of any given strain to produce disease; higher virulence means the pathogen can produce disease when present in very small numbers

Define bacterial resistance:

mutations, nosocomial infections, inapprporiate antibiotic use, and overprescribing cause resistance, where the medication isn't as effective at killing the bacteria

What are the most serious side effects of cephalosporins?

nephrotoxicity and anaphylaxis

Which of the following are common adverse effects of aminoglycosides and some other antibacterials?

ototoxicity (capable of hearing loss) and nephrotoxicity (capable of kidney damage)

What are the commonly-associated adverse effects of aminoglycosides?

ototoxicity and nephrotoxicity

What is the most serious side effect of levofloxacin (a fluoroquinolone)?

rhabdomyolysis

Define extended spectrum antibacterial agents:

these combine an antibiotic with a drug that inhibits bacterial production of beta-lactamase

Indications for amebicides?

used to treat diseases caused by amoeba, such as amoebic dysentery

Indications for antiretrovirals?

viruses (mostly HIV)

Describe four factors that contribute to the development of acquired resistance to antibacterial agents.

1. Mutations - genetic mutations that allow the bacteria to be resistant to antibiotic are passed on to subsequent generations of bacteria. 2. Nosocomial infections - hospital-acquired infections often produced by most resistant strains of bacteria; hospital patients are often immunocompromised and are especially susceptible to the organisms that cause nosocomial infections; the resistant organism is then spread to others. 3. Innappropriate antibiotic usage - when an antibiotic is stopped before the prescription is finished, some organisms survive; these are the ones with a genetic mutation making them resistant to the antibiotic; the stronger bacteria is then passed on to others. 4. Over-prescribing - antibiotics are completely ineffective against viral infections and should not be prescribed for them; they should also not be prescribing the strongest antibiotics unless they really have to.

Patients being treated for tuberculosis must take antibacterials for a very long time. Which of the following will most likely prevent resistance?

Administer several different antibacterials concurrently

Which of the following contributes to acquired resistance of bacteria to antibacterials?

Not completing all medications as prescribed, Mutations, Hospital-acquired infections

Describe the effect that repeated or prolonged tetracycline use can have on the teeth.

They can cause permanent yellow or gray staining of the teeth in children

Indications for penicillins?

bacterial infections

Indications for sulfonamides?

bacterial infections - Susceptible urinary tract infections

Indications for cephalosporins?

wide range of bacterial infections; prophylaxis