IID 10: Introduction to the ID Patient Flashcards
What is the innate immune response?
limits pathogen spread and activates adaptive immune response for a more targeted defense
What does activation of the adaptive immune response by the innate immune system involve? (3)
- phagocytosis
- antigen processing/presenting
- activation of adaptive immune response
What is antigen processing/presenting?
after the invading pathogen is broken down via phagocytosis, its antigens are processed and presented to the adaptive immune response to trigger further action
What are the key components of the innate immune response? (4)
- natural killer (NK) cells
- white blood cells
- cytokines
- complement proteins
What do natural killer cells do?
key role in identifying and eliminating infected or abnormal cells in the body
- target infected and tumour cells for self-destruction
- secrete interferon to block viral replication
- activate other immune cells
- recognize infected cells broadly rather than specific pathogens
- release perforin and granzymes, which cause lysis of the target cell
What do white blood cells do?
help to identify and destroy pathogens
- key to innate and adaptive immunity
- protect against infections by acting in connective tissues
- produced in bone marrow, then released via cytokines to target infection sites
What are the low, normal, and high values for white blood cells?
normal value: 4,000 – 11,000/mm3
- low value (< 4,000/mm3) – leukopenia
- high value (>11,000/mm3) – leukocytosis
What are the 2 types of white blood cells?
- granulocytes
- agranulocytes
What are granulocytes?
contain membrane-bound granules
- neutrophils
- eosinophils
- basophils
What are agranulocytes?
lack membrane-bound granules
- lymphocytes (B cells and T cells)
- monocytes
What is the order of white blood cell types from most to least abundant
Never Let Monkeys Eat Bananas
- neutrophils
- lymphocytes
- monocytes
- eosinophils
- basophils
What do neutrophils do?
phagocytize and destroy bacteria
- ‘band cells’ or ‘left shift’ = presence of immature neutrophils
What do B lymphocytes do?
secrete antibodies that bind to and mark pathogens for destruction
What do T lymphocytes do?
direct destruction of virus infected and mutated cells
What do monocytes do?
transform into macrophages (phagocytic cells)
What do eosinophils do?
role in body’s immune response to parasitic infections and allergic reactions
What do basophils do?
role in inflammation and mediation of allergic reactions
What do cytokines do?
signaling proteins that help regulate and direct immune responses during the innate immune process
List some cytokines. (4)
- histamine
- bradykinin
- acute-phase proteins
- interleukins
What does histamine do?
triggers local vasodilation, increasing blood flow and enabling faster white blood cell migration to infected tissues, promoting a quicker immune response
What does bradykinin do?
- promotes vasodilation
- activates pain receptors
- works with histamine to direct immune cells to infection sites while alerting the body through pain
What do acute-phase proteins do?
- quickly respond to injury or infection by activating complement and tagging pathogens for destruction
- ie. C-reactive protein (CRP) – levels can be measured in blood tests to monitor infection responses
What are interleukins?
chemical messengers that coordinate leukocyte activity, activating and enhancing immune responses to infections
What do complement proteins do?
work alongside the immune cells to help destroy pathogens and enhance the effectiveness of the immune response
Describe the steps of phagocytosis.
- ingestion of pathogen
- macrophage engulfs pathogen into a granule, which then fuses with a lysosome to begin digestion
- pathogen digestion
- lysosome’s enzymes break down the pathogen into smaller antigen fragments inside the macrophage
- antigen presentation
- macrophage displays these antigen fragments on its surface, becoming an antigen-presenting cell (APC) to activate the adaptive immune response
What is the complement system/cascade essential for?
essential for both innate and adaptive immune responses, activated by different immune pathways during infections
What does the complement system/cascade do?
- promotes inflammation, attracting phagocytes to the infection site for faster pathogen elimination
- enables opsonization, tagging pathogens to make them more recognizable to phagocytes for effective destruction
How does the complement system/cascade work?
membrane attack complex (MAC) is activated, causing cell lysis by breaking down infected cells, preventing infection spread
- overall, the system enhances immunity by triggering inflammation, marking pathogens, and causing cell lysis
What are the lymphocytes of the adaptive immune response and their function?
- helper T cells (CD4) recognize the antigen and activate B cells and cytotoxic T cells (CD8)
- B cells form plasma cells to produce antibodies and memory B cells to store viral memory for future protection
- cytotoxic T cells directly kill infected cells by releasing substances that stop viral spread
- memory T and B cells ensure a faster, stronger response if the virus reappears, providing long-term immunity
The Antibody Response
What is the primary immune response?
antibody production is delayed, taking 1-2 weeks to reach sufficient levels to fight the infection
The Antibody Response
What is the time delay?
immune system requires time to recognize pathogens and produce antibodies, often up to a week
The Antibody Response
What is the role of antibiotics?
support the immune system during severe infections
- bacteriostatic antibiotics slow pathogen growth
- bactericidal antibiotics kills pathogens
The Antibody Response
What do vaccines do?
create memory cells, allowing quicker antibody production during subsequent exposures
The Antibody Response
What is the secondary immune response?
memory cells ensure rapid and robust antibody production, providing immediate protection
The Antibody Response
Why are mild infections often resolved without antibiotics?
delayed response – immune system takes time to produce specific antibodies during the first exposure
The Antibody Response
What is antibiotic support?
severe infections may require antibiotics to provide temporary relief while the immune system builds its response
What are routes of transmission important for pharmacists? (4)
- self-protection
- patient education
- risk assessment
- improved care
What are the 3 contact routes of transmission?
- direct
- indirect
- droplet
What are some infections acquired by direct transmission?
- mononucleosis
- STIs
- respiratory viruses
What are some infections acquired by indirect transmission?
- norwalk virus
- rhinovirus
- RSV
What are some infections acquired by droplet transmission?
- meningococcus
- respiratory viruses
- COVID-19
Compare droplet transmission vs. indirect transmission.
droplet transmission:
- when an infected person coughs or sneezes, droplets containing the virus are released into the air
- if another person is within 1 to 2 meters, these droplets can land on their mouth, nose, or eyes
- these droplets may enter the respiratory system, leading to infection
indirect transmission:
- infected droplets land on surfaces like phones, computers, or other objects
- when another individual touches these contaminated surfaces, the virus can transfer to their fingers
- if they touch their nose or mouth, they may infect themselves
What are the types of personal protective equipment (PPE)?
- eye protection
- facemask
- isolation growth
- non-sterile gloves
What are the 3 non-contact routes of transmission?
- airborne
- vehicle
- vector-borne
What is airborne transmission?
- transmission via small aerosols that contain organisms in droplet nuclei or dusts
- can be spread via ventilation systems
- airborne particles can travel over larger distances and infect individuals not in close proximity
What are some infections that can be acquired by airborne transmission?
- tuberculosis
- measles
- chickenpox
- smallpox
- COVID-19
What are some precautions that can be taken to prevent transmission of airborne transmission?
- masks/PPE
- ventilation systems
- prevent spread through proper airflow control
What is vehicle transmission?
- transmission occurs through the exposure to an inanimate object, such as food or water, that has been contaminated with the pathogen
- point source: transmission contained within a localized area
- common source: transmission over a much larger geographic area
What are some infections that can be acquired by vehicle transmission?
- point source: infected batch of food at single
restaurant - common source: nationwide Listeria or E.coli outbreak linked to a meat processing plant or farm
What are some precautions that can be taken to prevent transmission of vehicle transmission?
food safety and disinfection standards
What is vector-borne transmission?
transmission by insect or animal vectors
- infectious agents are passed on through bites or contact with these vectors
What are some infections that can be acquired by vector-borne transmission?
- malaria (mosquitos)
- lyme disease (ticks)
What are some precautions that can be taken to prevent transmission of vehicle transmission?
- protective barriers (screens, nets, clothing)
- insecticides
- avoid exposure to bites
Compare droplet vs. airborne transmission.
droplet transmission:
- large droplets (>100 μm): travel short distances (1-2 meters) and stay airborne briefly
- medium droplets (5-100 μm): remain suspended longer but still follow a ballistic trajectory
airborne transmission:
- small droplets or aerosols (<5 μm): stay suspended in the air for long periods, enabling transmission over short or long distances
What are the 4 factors that must be considered when preparing to select antimicrobials?
- host factors
- pathogen factors
- drug factors
- significance
Preparing to Select Antimicrobials
Host Factors
- age
- weight
- immune status
- comorbidities
- allergies
- medication and medical history
- immunization history
- exposure risk
- symptoms and history of present illness
- risk factors for infection and immunosuppression
- travel and pets
What are the vitals signs and symptoms of infection?
signs:
- fever (↑ temp)
- tachycardia (↑ HR)
- hypotension (↓ BP)
- tachypnea (↑ RR)
What are the CNS signs and symptoms of infection?
signs:
- disorientation (A&O x 3 – person, place, time)
symptoms:
- headache
- confusion
- neck stiffness
- seizures
What are the HEENT signs and symptoms of infection?
symptoms:
- visual field defects
- photophobia
- sore throat
- dysphagia
What are the CVS/RESP signs and symptoms of infection?
signs:
- ↓ blood oxygenation (hypoxia)
- ↑ work of breathing
- ↓ breath sounds
symptoms:
- chest pain
- cough
- shortness of breath
- increased sputum
What are the GI signs and symptoms of infection?
symptoms:
- N/V/D
- pus or blood in stool
- abdo pain
What are the renal/GU signs and symptoms of infection?
signs:
- ↓ urine output
symptoms:
- flank pain
- dysuria
- frequency
- urgency
What are the skin signs and symptoms of infection?
symptoms:
- PRISH – pain, redness, immobility, swelling, heat
What are the non-specific signs and symptoms of infection?
signs:
- can be present in any infection
symptoms:
- myalgias
- chills
- rigors
- sweating
- anorexia
- fatigue
- malaise
- weight loss
Preparing to Select Antimicrobials
Pathogen Factors
identification begins with gram staining and progresses to advanced tests like MALDI-TOF to pinpoint the pathogen and guide antibiotic choice
Preparing to Select Antimicrobials
Drug Factors
selection depends on factors like tissue penetration, toxicity, and whether the antibiotic is bactericidal or bacteriostatic
Preparing to Select Antimicrobials
Significance
- early decisions rely on probable pathogens and resistance patterns
- treatments are refined as lab results become available to optimize effectiveness and minimize resistance
What is A&O x 3?
refers to if a patient is Alert & Oriented
- normally, a person should be oriented to person (who they are), place (where they are) and time (what day and approximate time it is)
- ie. if someone only knows who they are but not where they are or the date, they
would be categorized as A&O x 1 – this is a sign that they are disoriented, or confused, which may be due to infection
Laboratory and Diagnostic Tests
What are the patient assessment tests? (6)
- CBC with differential
- inflammatory markers (CRP, ESR)
- organ-specific markers (SCr, liver enzymes)
- blood gases
- analysis of bodily fluids (urine, cerebral spinal fluid, etc.)
- imaging (x-ray, ultrasound, etc.)
Laboratory and Diagnostic Tests
What are the pathogen assessment tests? (5)
- gram stain
- serological tests
- molecular tests
- culture
- sensitivity and resistance
Laboratory and Diagnostic Tests
What specimens can be cultured? (9)
- blood
- urine
- cerebral spinal fluid
- sputum
- pus
- peritoneal fluid
- semen
- vaginal secretions
- feces
What is the culture process?
essential for identifying the cause of infection and tailoring effective antibiotic treatments
What are the 3 key steps of the culture process?
- gram staining
- pathogen identification
- susceptibility testing
Culture Process
What is gram staining?
classifies bacteria as Gram-positive or Gram-negative based on cell wall thickness
- thicker cell walls retain a crystal violet stain (Gram-positive), while thinner walls do not (Gram-negative)
- this step helps narrow down potential pathogens and guides the initial selection of antibiotics.
Culture Process
What is pathogen identification?
- MALDI-TOF: identifies bacteria by analyzing ionized components through mass spectrometry and can sometimes detect resistance genes
- ELISA: uses antibodies to detect specific antigens, generating signals to confirm their presence
- chromogenic media: bacteria are cultured on agar plates with substrates that change colour, helping to identify pathogens
- PCR: amplifies bacterial DNA for identifying slow-growing or low-concentration organisms
Culture Process
What is susceptibility testing?
- disk diffusion (Kirby-Bauer Test): assesses bacterial sensitivity to antibiotics by observing the zone of inhibition around antibiotic disks
- E-test: determines the MIC by measuring the point where the elliptical inhibition zone meets an antibiotic gradient strip
- broth dilution: identifies both MIC and MBC by exposing bacteria to various antibiotic concentrations in a liquid medium
Culture Process
What are some other methods for susceptibility testing?
- advanced techniques like DNA microarrays and whole genome sequencing provide detailed insights into resistance genes and mutations
- antibiogram: summarizes local bacterial susceptibility patterns to help clinicians make empiric treatment decisions and reduce the use of broad-spectrum antibiotics
What type of antibiotic agents do immunocompromised patients require?
bactericidal – their immune system may struggle to eliminate pathogens effectively
What type of antibiotic agents do life-threatening infections and hard-to-reach areas (ie. brain, bone) require?
bactericidal – due to difficulty of drug penetration
Do penicillins act as bacteriostatic or bactericidal agents?
can act as bactericidal against certain bacteria, but bacteriostatic against others
- primarily bactericidal, but exceptions exist depending on the bacteria (ie. Enterococcus)
What are broad spectrum antibiotics?
effective against many bacteria
- useful for empiric treatment when the pathogen is unknown
What are narrow spectrum antibiotics?
targets specific bacteria
- used after pathogen identification
What are some considerations for pharmacists when determining whether to use broad spectrum or narrow spectrum antibiotics?
- use the narrowest spectrum antibiotic to prevent resistance (antimicrobial stewardship)
- tissue penetration varies (ie. nitrofurantoin works for bladder infections but not kidneys)
- adjust route, dose, and duration based on infection severity and site
- review the toxicity profile to ensure safety and minimize side effects
What is MIC?
minimum concentration of an antimicrobial agent required to inhibit bacterial growth
- key parameter in determining the effectiveness of an antibacterial agent
- measures the minimum concentration needed to stop bacterial growth, but not necessarily to kill
What is MBC?
minimum concentration of an antimicrobial agent required to kill bacterial cells
- focused on killing bacteria, while MIC inhibits growth
Is MIC or MBC more used in practice?
MIC is predominantly used to determine susceptibility patterns for bacterial pathogens
What are drugs with time-dependent activity?
these drugs are most effective when their concentration remains above the MIC for as long as possible
- in severe infections, frequent dosing (like every four hours) ensures that drug levels stay consistently above the MIC
- unlike concentration-dependent drugs, the peak concentration is less important
- instead, maintaining levels above the MIC is crucial, described using terms like “time
over MIC” or “AUC to MIC ratio - ie. penicillin, cephalosporins
What are drugs with concentration-dependent activity?
these drugs rely on achieving a high peak concentration relative to the MIC
- often dosed once daily at a high dose to maximize their effect, followed by a washout period to allow the drug to clear from the system, minimizing toxicity
- with these drugs, concentrations dip below the MIC between doses, but a higher peak concentration significantly enhances their effectiveness
- ie. aminoglycosides, fluoroquinolones
