Chapter 10: Drugs To Treat Infection - Antibiotics Flashcards
What are MDROs?
- multi drug-resistant organisms
- strains of bacteria that have developed resistance to many different types of antibiotics.
- often emerge due to the overuse of antibiotics leading to a decrease in their effectiveness
Give 3 examples of MDROs:
- methicillin-resistant staphylococcus aureus (MRSA)
- pseudomonas aeruginosa
- vancomycin-resistant enterococcus (VRE)
Antibiotics are used to treat or prevent infections by ________, specifically _______ infections. They are not effective against _______ infections.
- pathogens
- bacterial
- viral
Name the 2 types of antibacterials:
- bactericidal: agents that kill bacteria
- bacteriostatic: agents that slow down or stall the growth of bacteria
Name antimicrobials that do not treat bacterial infections:
- antivirals
- antifungals
- antiparastitics
Name some common bacterial infections:
- eye infections
- bacterial meningitis
- sinusitis
- upper respiratory tract infection
- gastritis
- pneumonia
- food poisoning
- UTI
- skin infections
- STI
What are the 4 ways that bacteria are classified?
- morphology (shape)
- gram straining
- encapsulation
- oxygen requirements
What are the 4 shapes that bacteria can be classified as?
- spheres (cocci)
- rods (bacilli)
- spirals
- helixes
Define gram straining.
A bacteriological laboratory technique used to differentiate bacterial species into gram-positive and gram-negative groups based on the physical properties of their cell walls
Define encapsulation
Encapsulated bacteria are protected from ingestion by phagocytes, thereby increasing bacterial virulence
Anaerobic bacteria are common in what areas?
- GI tract
- vagina
- dental crevices
- chronic wounds when blood supply is impaired
Name the 5 mechanisms of action that antibiotics have.
- inhibition of cell wall synthesis (most common)
- inhibition of protein synthesis (second largest class)
- alteration of cell membrane structure
- inhibition of nucleic acid synthesis
- antimetabolic activity
Define resident flora (microbiomes).
Bacteria that normally occupy a particular site in the body and do not usually cause disease
What is the difference between broad-spectrum and narrow-spectrum antimicrobials?
- broad-spectrum: kill many different species of bacteria. Increased likelihood of treating a causative pathogen, but secondary infections caused by certain antimicrobial-resistant pathogens commonly develop.
- narrow-spectrum: kill fewer different species of bacteria
Identifying the specific pathogen or microorganism using lab tests such as ______ ______ is important in selecting the correct antibiotic for the patient’s condition.
Gram straining
Name some conditions where the microorganisms in a person’s microbiome may cause disease.
- the use of antibiotics
- injury or surgery
- a weakened immune system
Name some conditions that gram-positive bacteria can cause.
- skin and soft tissue infections, heart valve infections, bone infections, and septicemia
- pneumonia, meningitis, middle ear infections
- pharyngitis or strep throat, pneumonia, wound and skin infections, sepsis, endocarditis
- endocarditis, UTI, prostaitis, intra-abdominal infection, cellulitis, wound infection, concurrent bacteremia
- toxic shock syndrome
- diphtheria
- anthrax
Name some conditions that gram-negative bacteria can cause.
- UTI, traveler’s diarrhea, pelvic inflammatory disease
- bloodstream infections
- wound or surgical site infections
- meningitis
- peritonitis
- plague
- cholera
- typhoid fever
What features do gram-negative bacteria have that can make it a potentially serious infection?
- enclosed in a protective cell wall that prevents WBC from ingesting the bacteria
- outer membrane protects the bacteria against certain antibiotics such as penicillin
- when disrupted, the outer membrane releases toxic substances (endotoxins) that contribute to the severity of symptoms
E. coli is a gram ______ bacteria.
Negative
Name the most common route of administration for antibiotics.
Enteral (GI) route
- pills, tablets, capsules, liquid
When should patients get antibiotics through IV?
- Patients manifesting systemic signs of infection such as hypotension or hypoperfusion
- antibacterials with poor bioavailability for systemic infections
- oral antibiotics cannot be tolerated (vomiting)
- oral antibiotics are poorly absorbed (malabsorption after intestinal Sx, impaired intestinal motility after opioid use)
- patient is critically ill, needing immediate effect or having impaired GI tract perfusion
What is the first-pass effect?
- often with orally administered drugs
- the process by which drugs are absorbed in the small intestine through the hepatic portal circulation and then directly transported to the liver for metabolism
What is a PICC line?
- peripherally inserted central catheter
- administers antibiotics directly into the systemic circulation
- useful for administering higher concentrations of medication
Antibacterial drugs are distributed by binding to ______ ______. Distribution of antibiotics within the tissues (penetration) varies with the ______ _____ ______.
- serum proteins
- site of infection
What are the 4 important pharmacodynamic parameters that are related to antibacterial efficacy?
- Minimal inhibitory concentration (MIC)
- Peak-to-MIC ratio
- Percentage of time above MIC
- 24-hour area under the concentration-time curve (AUC24)
Name the 3 general categories of antibacterials based on their concentration-related effects.
- Concentration-dependent activity
- Time-dependent activity
- Exposure-dependent activity
Describe dosing guidelines for antibacterials.
- timing of initial therapy is guided by urgency and severity
- severe illness: common to use broad spectrum antibacterial agents
Why is it bad if patients stop taking their antibiotic treatment before their full course is finished?
can promote resistance or the development of a superinfection and increase the risk of relapse
Name the most common side effect of antibiotics.
Antibiotic-induced diarrhea
Name some rare adverse effects from antibiotics that manifest specifically in the athletic population.
- relationship between ciprofloxacin (fluoroquinolones) and tendon injury
- ciprofloxacin may react with calcium rich foods like dairy or antacids
- tetracycline causes sensitivity to the sun
Name some types of conditions that would indicate antibiotic use.
- not serious but unlikely to clear up without antibiotics (acne)
- not serious but could spread to other people if not promptly treated
- supported by evidence suggesting that antibiotics could significantly speed up recovery (ex. Kidney infection)
- at high risk of more serious complications (ex. Cellulitis, pneumonia)
Antibiotic medication may be recommended for people who are more vulnerable to the harmful effects of bacterial infection, including:
- over 75 years old
- heart failure
- those who have to take insulin for diabetes
- weakened immune system
Name some broad spectrum beta lactam antibiotics.
- penicillins
- carbapenems
- cephalosporins
Describe what macrolides are used for, and name some examples.
- wide range of infections
- erythromycin, clarithromycin, azithromycin
Describe what tetracyclines are used for, and name some examples.
- broad-spectrum activity against a wide range of microorganisms including gram-positive and gram-negative bacteria
- bacteriostatic
- only effective against multiplying microorganisms
- doxycycline, minocycline
Which antibiotic is likely to cause photosensitivity? What can patients do to avoid risk from this?
- tetracyclines
- use skin protection, avoid prolonged exposure to sunlight and UV light
Describe what fluoroquinolones are used for, and name some examples.
- broad-spectrum
- bactericidal
- effective against both gram-negative and gram-positive bacteria
- ciprofloxacin, levofloxacin, ofloxacin
Ciprofloxacin is commonly administered for….
- upper respiratory tract
- sinus infections
Which antibiotic is associated with tendon pathology, including tendinitis and tendon rupture? Concomitant administration of ______ can make this worse.
- ciprofloxacin (fluoroquinolones)
- corticosteroids
Symptoms of fluoroquinolone-induced tendon injury may present how early and last for how long?
- within hours
- up to 6 months
What population is more at risk for developing fluoroquinolone-induced tendon injury?
Patients older than 60 years old, although it has been reported by people as young as 18 years old.
- athletic population
- those taking oral or injectable corticosteroids
Name some red flags indicated the start of fluoroquinolone-induced tendon injury.
- pain
- swelling
- inflammation of a tendon
Why should patients avoid skipping doses of antibiotics?
Can increase the risk of infection that is resistant to medication
Tetracyclines should not be taken _____ hr before eating or ____ hr after consuming dairy products or calcium fortified juices, multivitamins, or antacids.
- 1 hr
- 2 hr
Define collateral damage.
The development of resistance occurring in a patient’s nontargeted antibacterial flora (microbiome) that may cause a secondary infection
Name some antibiotics that are most likely to cause antibiotic-induced diarrhea:
- ampicillin
- amoxicillin
- cefixime
- cephalosporins, fluoroquinolones
- azithromycin, tetracycline
Name the symptoms of Clostridium difficile (antibiotic-induced diarrhea) that are a red flag:
- fever > 38.5 degrees Celsius
- 10 watery stools/day, possibly with blood or pus
- signs of significant dehydration
- abdominal pain with evidence of colitis on CT scan or endoscopy
Up to _____ of antibiotic prescriptions may be unnecessary, poorly chosen, or dosed incorrectly.
Half
