Infectious Disease 2 Flashcards
(113 cards)
1
Q
bacteria
A
- single-celled microorganisms w/ well-defined cell walls that can grow independently on artificial media w/o the need for other cells
- can be classified according to shape
2
Q
spherical bacterial cells
A
cocci
3
Q
rod-shaped bacteria
A
bacilli
4
Q
spiral-shaped bacteria
A
spirilla or spirochetes
5
Q
bacteria can also be classified according to:
A
- response to staining (gram-positive, gram-negative, or acid-fast)
- motility (motile or nonmotile)
- tendency toward capsulation (encapsulated or non encapsulated)
- capacity of form spores (sporulating or nonsporulating)
- aerobic: oxygen is needed to replicate and develop
- anaerobic: they can sustain life in an oxygen-poor (anaerobic)
6
Q
bacteria are _________ microorganisms
A
unicellular
7
Q
a rigid ______ _______ surrounds the bacterial cell
A
cell wall
8
Q
bacteria lack a true _______ _______
A
nuclear membrane
9
Q
bacteria require nourishing mediums to provide ________ _________ to maintain fxn
A
metabolic substrates
10
Q
gram positive vs gram negative bacteria
A
Gram-positive:
- have simple cell walls with a thick layer of peptidoglycan
- stain purple
Gram-negative:
- more complex cell walls, less peptidoglycan, which is located between 2 membranes
- More resistant to antibiotics
- stains pink
11
Q
pathogenic effects of bacteria
A
- bacteria multiply, competing w/ host (human) cells for essential nutrients
- may directly harm human cells by releasing toxic substances
- may cause an immune response that’ll ultimately damage human tissue along w/ the invading bacteria
- not all bacteria in the human body are harmful
12
Q
bacterial infections
A
- Enterobacteriaceae
- Clostridioides (formerly Clostridium) difficile infections
- Staphylococcal infections
- Streptococcal infections
- Streptococcus pneumoniae
- Clostridial Myonecrosis (Gas Gangrene)
- Pseudomonas
13
Q
Clostridioides (formerly Clostridium) difficile infections (CDI) - organismal level
A
- anyone, but person 65 yrs and older are at > risk
- primarily in health care facilities
- diarrhea after antibiotic consumption
14
Q
Clostridioides (formerly Clostridium) difficile infections (CDI) - system level
A
GI system
15
Q
Clostridioides (formerly Clostridium) difficile infections (CDI) - organ level
A
- transmission of C. difficile occurs via fecal-oral route following contamination of hands of HCWs and patients w/ oral ingestion of causative organism
- dx is confirmed by ID’ing toxins in stool
16
Q
Clostridioides (formerly Clostridium) difficile infections (CDI) - tissue level
A
hand washing = best prevention to reduce infection and injury
17
Q
Clostridioides (formerly Clostridium) difficile infections (CDI) - cellular and chemical level
A
prompt discontinuation of antibiotic agent w/ administration of oral metronidazole (flagyl) and fluids PRN
18
Q
Staphylococcal Infections - organismal level
A
- individuals w/ diabetes who are insulin dependent, HIV +, receiving hemodialysis, IV drug users, persons w/ chronic skin lesions, and surgical and burn patients
- occurs anytime
- infection usually produces suppuration, abscess formation, lesions
- infective syndromes include osteomyelitis, infections of burns or surgical wounds, bacterial arthritis, septicemia, bacterial endocarditis, a toxic shock syndrome
- consumption of toxins is a common cause of food poisoning
19
Q
Staphylococcal Infections - system level
A
integumentary
20
Q
Staphylococcal Infections - organ level
A
- S. aureus spreads by direct contact
- most common human colonization of S. aureus are the nares (nasal passages, bones, joints, kidney, lung, and heart valves)
- gram stain & culture of the organism from the infected site, blood or other fluid is usually dx
- polymerase chain rxn (PCR)-based assays are becoming more available for rapid dx
21
Q
Staphylococcal Infections - tissue level
A
hand washing and PPE
22
Q
Staphylococcal Infections - cellular & chemical level
A
antibiotics
23
Q
Streptococcal Infections - organismal level
A
- all ages
- occurs anytime
- strep throat = infection occurs most commonly from Oct-Apr in children 5-10 yrs
- skin infections to acute self-limited pharyngitis to post infectious syndromes of rheumatic fever and post streptococcal glomerulonephritis
24
Q
Streptococcal Infections - system level
A
multiple systems
25
Streptococcal Infections - organ level
- diverse organ systems w/ multiple transmission modes
- Group A streptococci (GAS) is typically transmitted via contact w/ respiratory droplets
- Group B (GBS)--neonatal pneumonia, meningitis, and sepsis
26
Streptococcal Infections - tissue level
hand washing and PPE
27
Streptococcal Infections - cellular and chemical level
tx is w/ antibiotics to avoid post streptococcal syndromes
28
gangrene
the death of body tissue, usually associated w/ loss of vascular (nutritive, arterial circulation) supply and followed by bacterial invasion and putrefaction
29
3 major types of gangrene
dry, moist, and gas gangrene
30
dry and moist forms of gangrene result from....
loss of blood circulation d/t various causes
31
Clostridial myonecrosis (gas gangrene) occurs in....
wounds infected by anaerobic bacteria, leading to gas production and tissue breakdown
32
Clostridial Myonecrosis (gas gangrene) - organismal level
- can affect anyone
- the anaerobic conditions necessary to foster clostridial growth are uncommon in human tissues and are produced only in the presence of extensive devitalized tissue
- skin darkens, then skin lesions and deep wounds form
33
Clostridial Myonecrosis (gas gangrene) - system level
integumentary
34
Clostridial Myonecrosis (gas gangrene) - organ level
dx by blood tests, imaging of structures, surgery, fluid or tissue culture
35
Clostridial Myonecrosis (gas gangrene) - tissue level
early, immediate intervention is necessary w/ surgical debridement and excision of necrotic tissue
36
Clostridial Myonecrosis (gas gangrene) - cellular and chemical levels
antibiotics
37
Pseudomonas (Pseudomonas Aeruginosa) - organismal level
- anyone, "swimmer's ear", post-op
- most common hospital and nursing home-acquired pathogens
- fever, tachypnea, vascular thrombosis, tachycardia, hypotension, and delirium, which can lead to renal failure, lesions and wounds, acute respiratory distress syndrome, and death
- characteristic fruity odor (sweet, grape like odor) w/ a blue-green exudate that forms a crust on wounds
38
Pseudomonas (Pseudomonas Aeruginosa) - system level
integumentary, circulatory, respiratory
39
Pseudomonas (Pseudomonas Aeruginosa) - organ level
dx requires isolation of Pseudomonas organism in blood, spinal fluid, urine, exudate, or sputum culture
40
Pseudomonas (Pseudomonas Aeruginosa) - tissue level
hand washing, PPE
41
Pseudomonas (Pseudomonas Aeruginosa) - cellular level
antibiotic therapy is initiated immediately w/ 2 antipseudomonal drugs
42
bactericidal
drugs that typically kill/destroy bacteria
43
bacteriostatic
drugs that do not actually kill bacteria but limit their growth and proliferation
44
basic mechanisms of antibacterial drugs
1. inhibition of bacterial cell wall synthesis and fxn
2. inhibition of bacterial protein synthesis
3. inhibition of bacterial DNA/RNA synthesis and fxn
45
1. inhibition of bacterial cell wall synthesis and fxn - rigid and firm cell wall
protein-polysaccharide structures (peptidoglycan)
46
1. inhibition of bacterial cell wall synthesis and fxn - mechanism of action
- drugs cause inadequate production of peptidoglycans or other structural components w/in the cell wall
- some drugs directly punch holes in the bacterial cell membrane, destroying the selective permeability and separation of internal from external environment
- drugs act as detergents that break apart the phospholipid bilayer, creating gaps and leaks in the bacterial cell membrane
47
2. inhibition of bacterial protein synthesis - mechanism of action
- these drugs enter the bacterial cell and bind to specific ribosomal subunits → affinity for bacterial ribosomes > human ribosomes
- binding of the drug to the ribosome either blocks protein syntehses/causes the ribosome to misread the messenger RNA (mRNA) codes → production of meaningless/nonsense proteins
48
3. inhibition of bacterial DNA/RNA synthesis and fxn - mechanism of action
- folic acid serves as an enzymatic cofactor in several rxns, including synthesis of bacterial nucleic acids and certain essential amino acids
- drugs inhibit bacterial nucleic acid synthesis by inhibiting the production of folic acid
49
resistance to antibacterial drugs
- certain bacterial strains have a natural/acquired defense mechanism against specific anti-bacterial drugs
- enables the strain to survive the effects of the drug and continue to grow and reproduce similar resistant strains, thus representing a genetic selection process in which only the resistant strains survive the drug
50
antibiotic stewardship
antibacterial drugs should be used carefully and not overused
51
control problem of bacterial resistance
identify the specific pathogenic bacteria leads to the use of more selective agents → administering selective agents as opposed to broad spectrum antibiotics may help attenuate and kill resistant strains more effectively
52
common side effects of antibacterial drugs - hypersensitivity rxns
skin rashes, itching, and respiratory difficulty (such as wheezing)
53
common side effects of antibacterial drugs - GI problems
- nausea, vomiting, diarrhea
- usually not serious but may be bothersome if they continually interrupt therapy
54
viruses are sub cellular organisms made up of only an _____ or a ______ nucleus covered w/ ________
RNA; DNA; proteins
55
what is the smallest known organism, visible only through an electron microscope?
virus
56
viruses are completely dependent on ______ cells and can't replicate unless they invade a ______ cell and stimulate it to participate in the formation of additional virus particles
host
57
are viruses susceptible to antibiotics?
no
58
antiviral medications
can mitigate (moderate) the course of the viral illness by interrupting the viral replication process at one or more steps
59
classification of viruses
**just know what viruses are DNA or RNA viruses
60
characteristics of viruses
- don't contain any of the cellular components (e.g., ribosomes, ER) necessary to replicate itself or synthesize proteins and other macromolecules
- contains only the genetic code (viral genome) that will produce additional viruses
61
viral replication
- to replicate, it must rely on the biochemical machinery of the host cell
- invades host cell, take control of the cell's metabolic fxn, and uses its macromolecular synthesizing apparatus to crank out new viruses
- often incapacitates the infected cell so that the infected cell can't carry out its normal physiological activities
- virus is released by process of exocytosis, leaving the host cell relatively intact (although still infected w/ the original virus)
- host cell may simply be destroyed (undergo lysis), releasing viral offspring
62
lysis of host cell in viral replication
results in the release of the virus and the death of the cell and may stimulate the production of inflammatory mediators (prostaglandins, kinins, etc.) which create a hypersensitivity response
63
viral infections - blood borne viral pathogens
HBV, HCV, HIV
64
viral infections - Herpesviruses
- Varicella-Zoster Virus (Herpesvirus Type 3)
- Infectious Mononucleosis (Herpesvirus Type 4)
- Cytomegalovirus (Herpesvirus Type 5)
65
viral infections - Viral Respiratory Infections
- Influenza
- COVID-19
66
blood borne viral pathogens - Hepatitis B
- HBV can be transmitted to HCWs via percutaneous injuries or by direct/indirect contact w/ blood
- pre-exposure HBV vaccination of HCWs who are at risk (e.g., those who work in an area likely to have contact w/ blood and body fluids) is strongly recommended
67
blood borne viral pathogens - Hepatitis C
accidental percutaneous injuries (needle sticks/cuts w/ sharp instruments) are the highest risk vehicle for transmission to HCWs from people w/ acute or chronic HCV
68
the incubation period for HCV is ___ to ___ weeks, and nearly all individuals w/ acute infection will have _____ HCV infection
6-7 weeks; chronic
69
more than ____% of all people w/ HCV develop chronic hepatitis
75%
70
is there a vaccine against HCV available?
no
71
what is critical to prevent transmission of hepatitis-contaminated body fluids?
strict adherence to hand washing and standard precautions
72
Type 1 Herpesvirus
Herpes simplex virus (HSV)
73
Type 2 Herpesvirus
Herpes simplex virus (HSV)
74
Type 3 Herpesvirus
Varicella-zoster virus (VZV)
75
Type 4 Herpesvirus
Epstein-Barr infectious mononucleosis virus (EBV)
76
Herpesviruses
- Greek word for herein = "to creep"
- known HHVs divided by genomic and biologic behavior into 8 types
- intermittent, asymptomatic shedding is common and is the typical time of transmission
- infants born to women w/ genital herpes can be infected w/ HSV when they pass through an infected birth canal
77
approximately _____% of Americans older than 12 years harbor ______ which is usually responsible for cold sores
70%; HSV-1
78
_____% older than 12 years have _______
20%; HSV-2
79
pathogenesis of herpesviruses
- primary infection occurs through a break in the mucous membranes of the mouth, throat, eye, or genitals via minor abrasions the skin
- local multiplication occurs, followed by viremia and systemic infection w/ a subsequent lifelong latent infection and periodic reactivation of the virus
- various disturbances such as physical/psychological stress can disrupt the delicate balance of latency, and reactivation of the latent virus occurs
80
what does primary HSV-1 (1st episode) typically affect?
mouth and oral cavity, causing vesicles in the mouth, throat, and around the lips
81
HSV-2 is most often acquired through ___________
sexual contact
82
primary HSV-2 causes vesicles to form in the ___________
genitourinary tract
83
systemic sx of herpesvirus occasionally noted:
headache, malaise, myalgias, and fever
84
can primary infection be sx or asx?
asx
85
what reduces the risk of neonatal herpes in mothers known to be shedding the virus?
C-section
86
recurrent herpes simplex virus is best treated w/ _________, and recurrent genital disease requires ________ precautions during sexual activity in addition to meds
acyclovir; barrier
87
HCWs can protect themselves rom acquiring HSV by adhering to standard precautions and ____________ before all client contact and by the use of appropriate barriers such as a _________, _________, or _________ dressing to prevent hand contact w/ the lesion
handwashing; mask, gloves, or gauze
88
Varicella Zoster Virus (VZV) is HHV-3 and is known as _________ or ________
chickenpox; shingles
89
approximately _____% to ____% of the population develops the secondary, or reactivation, form of VZV, resulting in __________
10-20%; herpes zoster/shingles
90
adults older than ______ years and anyone who is immunocompromised (e.g., HIV infection, chemo, corticosteroid therapy, or cancer) are at ________ risk
50; greater
91
is varicella zoster virus highly contagious?
yes
92
the period of communicability of varicella zoster virus extends from ____ to ____ days before the onset of the rash through the first ____ to ____ days or until all lesions have formed crusts
1-2; 4-5
93
infectious mononucleosis (herpesvirus type 4) is an acute infectious disease caused by __________
Epstein-Barr virus (EBV)
94
infectious mononucleosis may be seen at any age, but it primarily affects __________ and __________
young adults; children
95
transmission of infectious. mononucleosis
through contact w/ oral secretions, blood, or transplanted organs infected w/ the virus
96
infectious mononucleosis is probably contagious before or after sx develop?
before - until fever subsides and oral and pharyngeal lesions disappear
97
what should the person w/ infectious mononucleosis be cautioned against engaging in?
excessive activity, especially contact sports, which could result in splenic rupture or lowered resistance to infection - usually appropriate for a period of at least 1 month
98
Respiratory Syncytial Virus (RSV)
causes annual outbreaks of pneumonia, bronchiolitis, and tracheobronchitis in infants and very young children and is the main cause of hospitalization for a respiratory illness in this group
99
usually people shed RSV for ___ to ___ days, but young infants may shed the virus for as long as ___ to ___ weeks
3-8; 3-4
100
what can rapidly dx RSV?
by viral antigen identification of nasal washings using an ELISA or immunofluorescent assay (IFA)
101
tx of RSV
hydration, humidification of inspired air, and ventilatory support as needed
102
cause of influenza
influenza viruses A or B and occurs in epidemics btwn late fall and early spring
103
mode of transmission of influenza
from person to person by inhalation of aerosolized virus or direct contact
104
onset of influenza
usually abrupt, w/ high fever, chills, malaise, muscular aching, headache, sore throat, nasal congestion, and nonproductive cough
105
how long does a fever last in influenza?
1-7 days (usually 3-5)
106
how can influenza infection progress rapidly?
first few days, causing pneumonia and respiratory failure, particularly in high-risk groups
107
secondary bacterial pneumonia may also develop in influenza, usually ____ to ____ days after the onset of viral sx, particular in the _______ adult
5-10; older
108
early dx of influenza can result in the use of ________ to minimize the intensity and duration of sx, especially those at _______ risk for complications
antivirals; high
109
COVID-19
viral disorder characterized by:
- high fever
- cough
- dyspnea
- chills
- persistent tremor
- muscle pain
- headache
- sore throat
- a new loss of taste and/or smell
- other sx of viral pneumonia
110
severe cases of COVID-19
a myriad of coagulopathy associated sx:
- blood coagulation
- thrombosis
- acute respiratory distress syndrome
- seizures
- heart attack
- stroke
- multiple cerebral infarctions
- kidney failure
- catastrophic antiphospholipid antibody syndrome and/or disseminated intravascular coagulation
111
COVID-19 in younger patients
rare inflammatory syndromes are sometimes associated:
- atypical Kawasaki syndrome
- toxic shock syndrome
- pediatric multisystem inflammatory disease
- cytokine storm syndrome
- SARS-CoV-2 in the genus BETACORONAVIRUS is the causative agent
112
viral resistance
- viruses can mutate and alter their structural or functional characteristics so that previously effective drugs will be unable to control specific viral infections adequately
- efforts should be made to limit the indiscriminate or inappropriate use of antiviral drugs
113
Interferons
- endogenous substances that exert nonspecific antiviral activity
- the proteins synthesized by the infected cell as part of the immune response to viral infection, and these substances enable healthy cells to resist infection from a wide array of viruses
