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Infectious Disease (Phase II) > Infectious Disease > Flashcards

Infectious Disease Flashcards

1
Q

Describe shape of filamentous bacteria

A

“mold-like” (look like plants sprouting up)

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2
Q

What shape is streptococcus?

A

Chains of cocci

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3
Q

Difference between gram positive and negative bacteria? What color are each on a gram stain?

A

Gram positive have thick peptidoglycan layer, appear purple; gram negative have thin peptidoglycan layer and appear red/pink

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4
Q

Features unique to gram positive bacteria

A

Teichoic acid (in membrane)

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5
Q

Features unique to gram negative bacteria

A

LPS, presence of an outer membrane, porins

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6
Q

Which immune system component recognizes peptidoglycan in bacteria?

A

TLR2

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7
Q

Where is penicillin binding protein found? What does it do?

A

Peptidoglycan layer of gram negative bacteria; confers resistance to penicillins

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8
Q

Where is lipid A (LPS) found? What does it do?

A

Outer membrane of gram negative bacteria; toxic part of LPS (causes sepsis)

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9
Q

Which immune system component recognizes lipid A in bacteria?

A

TLR4

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10
Q

What is the antigenic domain of LPS?

A

O antigen (also highly variable)

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11
Q

What bacterial virulence factor is important in the production of biofilms?

A

Capsule

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12
Q

What immune system component recognizes bacterial flagella?

A

TLR5

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13
Q

What process do bacteria use to replicate?

A

Binary fission

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14
Q

What are the phases of bacterial growth? When his doubling time measured? When are bacteria most susceptible to antibiotics?

A

Lag phase, log phase, stationary phase, death phase; log phase; log phase

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15
Q

What are the four classes of bacteria with respect to oxygen?

A

Aerobe, anaerobe, facultative aerobe/anaerobe, microaerophile

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16
Q

Examples of aerobe bacteria?

A

Mycobacterium TB, bacillus anthracis, bacillus subtilis

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17
Q

Examples of anaerobe bacteria?

A

Clostridium botulinum, bacterioides fragilis

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18
Q

Examples of facultative anaerobe bacteria?

A

Shigella dysenterae, staph A

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19
Q

Examples of microaerophile bacteria?

A

Campylobacter jejuni, H pylori

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20
Q

What bacteria is a common cause of hospital-acquired infections? Why?

A

Pseudomonas aeruginosa; it has very low nutrient requirements which facilitates transmission (can grow anywhere)

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21
Q

What bacteria is associated with “deep penetrating trauma” injuries?

A

Clostridium tetani

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22
Q

What type of bacteria does NOT grow on MacConkey agar?

A

Gram positive

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23
Q

Describe the genetic material encoded by plasmids and their replication

A

Usually confers selective advantage (e.g. antibiotic resistance, virulence factors) rarely encode for essential genes; plasmids are self replicating (can be uni-directional or bi-directional)

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24
Q

What type of bacteria are associated with type III secretion systems?

A

Gram negative bacteria

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25
Q

4 possible mechanisms of genetic transmission in bacteria

A

Transposition, transformation, transduction, conjugation

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26
Q

What type of bacterial genetic transmission involves transfer of “naked” DNA fragments?

A

Transformation

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27
Q

“Mobile genetic elements that often code for antibiotic resistance genes in bacteria but are incapable of self-replication are called what?”

A

Transposons

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28
Q

F factor and R factor are examples of what?

A

Plasmids

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29
Q

Types of transposons

A

Replicative (leaves copy behind) and non-replicative (does not leave copy behind)

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30
Q

What type of bacterial genetic transmission is associated with phages and lysis?

A

Transduction

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31
Q

What is the difference between plasmid transfer and Hfr transfer?

A

In plasmid transfer, only the plasmid is transferred; in Hfr transfer, donated genes (can be chromosomal and plasmid) are integrated into the chromosome

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32
Q

Examples of genetic material conferred by R plasmids?

A

Antibiotic resistance, resistance to heavy metals, synthesizing virulence factors

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33
Q

What is the catalase test used for with respect to gram positive cocci?

A

Differentiate between staphylococcus (catalase positive) and streptococcus (catalase negative)

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34
Q

What indicates a positive catalase test as opposed to a negative catalase test?

A

Positive catalase test will exhibit effervescent bubbling, whereas negative will show no bubbling

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35
Q

What disease is associated with infection with catalase positive organisms?

A

Chronic Granulomatous Disease

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36
Q

Important staph A virulence factors and their functions

A

Protein A (inhibits complement by binding Fc portion of IgG), coagulase (inhibits PMNs from accessing it), catalase (reduces phagocytic killing by converting H2O2 to H2O), FnBP (tissue adherence), alpha-toxin (damages and lyses leukocytes, limiting host response, releases tissue-damaging substances)

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37
Q

List all the “toxin diseases” caused by staph A

A

Rapid food poisoning (staphylococcal enterotoxin A binds MHC to ill-fitting peptide widely and immediately causing cytokine storm), scalded skin syndrome (attack on desmoglein 1 in kiddos), toxic shock syndrome (remember packing, e.g. tampon, nasal surgery, liposuction)

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38
Q

Staphylococcus epidermis

A

 Commonly found on prosthetics (e.g. heart valve replacements or pacemakers)
 Novobiocin sensitive (unique to staph epidermis)

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39
Q

“Coagulase negative, novobiocin resistant staph”

A

Staphylococcus saprophyticus

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40
Q

Staphylococcus saprophyticus

A

o Gram positive, coagulase negative, novobiocin resistant
o Normal flora of female genital tract and perineum
o 2nd most common cause of UTIs and cystitis in young women
o Can produce biofilms on urinary catheters
o Produces abundant urease

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41
Q

Where would you see PV leucocidin?

A

In community acquired MRSA (absent in HA MRSA)

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42
Q

Group A streptococci

A

Streptococcus pyogenes

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43
Q

Group B streptococci

A

Streptococcus agalacticae

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44
Q

Group D streptococci

A

Streptococcus bovid

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45
Q

Group A streptococci virulence factors and their functions

A

M protein (inhibits opsonization, immunogenic, adherence), C5a peptidase (inhibits C5a), streptolysin O and S (RBC and platelet lysis, release of lysosomal enzymes)

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46
Q

Group A streptococci virulence factors and their functions

A

M protein (inhibits opsonization, immunogenic, adherence), C5a peptidase (inhibits C5a), streptolysin O and S (RBC and platelet lysis, release of lysosomal enzymes)

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47
Q

Relationship between strep and acute rheumatic fever?

A

Streptococcus pyogenes’ M protein looks like a surface protein on cardiac myocytes (molecular mimicry), so Ab developed against M protein will attack cardiac myocytes, causing rheumatic fever (a type II hypersensitivity reaction)

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48
Q

What are the only two autoimmune sequelae after a strep infection

A

Acute rheumatic fever (type II hypersensitivity) and glomerulonephritis (type III hypersensitivity)

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49
Q

Scarlet fever symptoms and cause

A

Fever, strawberry tongue, erythematous sandpaper-rash after streptococcal pharyngitis; erythrogenic toxin (ET) from strep (note this is toxin-mediated, not autoimmune)

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50
Q

Streptococcus agalacticae

A

o Gram positive, catalase negative
o Beta or gamma hemolytic
o Bacitracin resistant
o Capsule contains sialic acid

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51
Q

Viridans streptococci examples and characteristics

A

S mutans, S sanguis)
o Alpha hemolytic
o Optochin resistant
o Insensitive to bile

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52
Q

Streptococcus pneumoniae characteristics

A 
o	Rust-colored, odorless, mucoid sputum
o	Alpha hemolysis
o	Sensitive to optochin
o	Capsule most important virulence factor, identified by quellung reaction
o	Diplococci, lancet shaped
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53
Q

Strep pneumoniae virulence factors

A

Capsule (most important, binds factor H to avoid complement), pneumolysin (stimulates autolysins, lyses red blood cells and platelets, stimulates release of lysosomal enzymes)

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54
Q

Predisposing factors to strep pneumoniae infection

A

Absence of spleen (predisposes to all capsulated bacteria), HIV, sickle cell disease

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55
Q

Bacillus anthracis infection symptoms and virulence factors

A

Cutaneous inf: “Woolsorter’s disease” - black “eschar” surrounded by vesicles; virulence factors include capsule (presence of glutamic acid unique to bacillus anthracis) and exotoxin (PA, EF, LF)

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56
Q

Clostridium perfringens virulence factors

A

Exotoxins (cytotoxins): alpha toxin, lecithinase, phospholipase

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57
Q

Clostridium perfringens lab identification

A

Double zone of hemolysis, positive Nagler reaction

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58
Q

List all toxins produced by clostridium difficile

A

A-toxin (enterotoxin), B-toxin (cytotoxin), CDT (C difficile transferase)

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59
Q

Release of what neurotransmitter(s) is blocked by clostridium botulinum toxin?

A

ACh

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60
Q

Release of what neurotransmitter(s) is blocked by clostridium tetani toxin?

A

GABA, glycine

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61
Q

Patients at high risk for clostridium retain infection

A

Geriatric patients, IV drug users

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62
Q

E coli lab presentation

A

Gram negative rod, facultative anaerobe, ferments lactose +, indole test + (unique)

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63
Q

Diseases caused by E coli

A

Hemolytic-uremic syndrome, gastroenteritis, UTI, neonatal meningitis (“any bacteria with a capsule capable of causing meningitis”)

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64
Q

E coli virulence factors and diseases they’re implicated in, if applicable

A

Endotoxin (septicemia), exotoxin, hemolysins (alpha hemolysin implicated in HUS), adherence factors/pili (UTIs, gastroenteritis), capsule (meningitis)

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65
Q

Salmonella lab identification

A 
o	Gram negative rod
o	Lactose negative
o	Produce H2S (distinguishes from shigella)
o	Intracellular growth
o	Encapsulated
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66
Q

Salmonella Enterica ser. Typhimurium diseases

A 
o	Gastroenteritis (6-72 hrs after; non-bloody diarrhea, N/V)
o	Bacteremia (pediatric + geriatric patients)
o	AIDS and sickle-cell patients more susceptible
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67
Q

Salmonella Enterica ser. Typhi diseases

A

Enteric (typhoid) fever:
 Gradually increasing, remittent fever
 10-14 days incubation period
 Asymptomatic carriers (e.g. “typhoid Mary”)

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68
Q

Shigella characteristics and diseases

A

o Non-motile
o Gram negative, lactose negative, H2S negative
o Very low inoculum needed (“Salmonella is wimpy, shigella is not”)
o Shigellosis (caused by S dysenteriae: watery diarrhea followed by tenesmus, bloody mucoid diarrhea)
o Bacteria are acid-resistant

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69
Q

Proteus Mirabilis

A

o UTI, staghorn calculus
o Gram negative, lactose negative (white colonies on MacConkey)
o Produce abundant urease (“ammonia smell”)
o Concentric circles on culture
o “Sheen on BAP”
o “Swarming” behavior

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70
Q

Pseudomonas aeruginosa presentation and lab ID

A

o “Wet” reservoirs (e.g. pool with the water slide, PT hot tubs, disinfectant solutions, sinks, ventilator)
o Oxidase positive, gram negative rods, fruity odor, blue-green in color (pyocyanin and pyoveridin), beta hemolytic

71
Q

Disease associated with pseudomonas aeruginosa

A

Cystic fibrosis (thick mucus layer ideal fro pseudomonas to grow)

72
Q

Pseudomonas aeruginosa virulence factors

A

Pili, flagella, capsule (biofilms; catheters), endotoxin (LPS), exotoxin A (blocks protein synthesis in eukaryotes via inactivation of elongation factor 2)

73
Q

Vibrio cholerae

A

 Tag: super frequent watery diarrhea + recent international travel
 Virulence: pili, adhesins, Cholera toxin (incr. ion secretion by epithelial cells; impaired salt resorption)
 No person-to-person transmission
 Tx: fluid + electrolytes (dehydration greatest danger)

74
Q

2 pathways of vibrio vulnificus transmission

A

Transmission via direct contact with contaminated seawater or eating contaminated uncooked seafood

75
Q

Campylobacter jejuni

A

o Requires specific media: “campy plate” (“selective agar at 42 degrees celsius…”)
o Zoonotic pathogen (birds; can contract from contaminated chicken)
o Corkscrew shape + flagella for invasion
o #1 cause of diarrhea in U.S. (sx diarrhea, abd pain, fever)
o Can lead to Guillan-Barre Syndrome (progressive neuropathy: paralysis, pain, muscle weakness, sensory loss)

76
Q

Heliobacter Pylori

A

o Gram negative, oxidase positive, helical, with flagella
o Survives low gastric pH (acid-inhibitory protein, urease buffers pH)
o Ulcers, stomach cancer
o Dx: stool antigen (if active), serum Ab (persists beyond active disease), heliobacter breath test

77
Q

Neisseria common features

A

Gram negative, oxidase positive non-motile diplococci

78
Q

Neisseria meningotidis virulence factors

A

Pili, capsule, endotoxin (these 2 interfere with complement), sigA protease, antigenic variation, siderophores (scavenge iron from environment, our defense = hepcidin)

79
Q

Diseases associated with Neisseria gonorrheae

A

Urethritis, cervicitis; neonatal conjunctivitis; arthritis (after disseminated)

80
Q

Neisseria gonorrheae pathogenesis

A

Attaches to urogenital epithelia, endocytosed, then submucosa, then bloodstream,

81
Q

Neisseria gonorrheae virulence factors

A

Same as N. meningitides but with abx resistance and no capsule:
Pili, endotoxin, sigA protease, antigenic variation, siderophores

82
Q

Bordatella Pertussis

A

o Whooping cough (coughing, choking, gasping, sometimes followed by vomiting; “cough cough wheeze”)
o Bordet-Gengou agar (charcoal-nicotinamide)
o Adhesion via filamentous hemagluttinin
o Pertussis toxin causes wild lymphocytosis
o Tropism for ciliated cells (destroyed by tracheal cytotoxin + adenylate cyclase)
o Highly contagious
o Capsule

83
Q

Haemophilus influenzae

A

o Very small gram negative coccobacilli
o Chocolate agar (NAD, hematin)
o Meningitis, epiglottitis
o Pili, OMPs, capsule (basis for vaccine), endotoxin

84
Q

Haemophilus ducreyi

A

o Very small gram negative coccobacilli
o Chocolate agar (NAD, hematin)
o Chancroid (genital ulcerative lesion, common in Africa Asia South America, incr. AIDS transmission)

85
Q

Legionella pneumophila

A

o Gram negative (stains poorly)
o Facultatively intracellular (alveolar mph)
o Special growth medium - BCYE (buffered charcoal yeast extract) - cysteine & iron
o Respiratory issues + diarrhea (also fever)
o Parasitizes amoeba in wild
o Lukewarm water (shower, A/C units) d/t biofilm

86
Q

Acinetobacter

A

o Aquatic environments (e.g. irrigating solution, IV solution
o Grows in “fluid” organ systems (lungs, CSF, urine)
o Resistance to multiple abx

87
Q

Chlamydia general characteristics

A

o Biphasic life cycle (elementary body = infectious, reticulate body = replicative)
o Intracellular life cycle
o Tropism for certain cell types (e.g. squamocolumnar)
o 1st urine void in the morning to get the sloughed off epithelial cells

88
Q

Chlamydia trachomatis serovars & symptoms

A

o A-C: chronic conjunctivitis (more common in developing countries, carried by fomites + flies)
o D-K: Inclusion conjunctivitis, infant interstitial pneumonia and genital infections (similar to gonorrhea, initial sx absent, can lead to infertility)
o La, L2, L3: Lymphogranulosa venereum (painless ulcer leads to unilateral lymphadenopathy and lymphatic infection)

89
Q

Listeria characteristics

A

o Gram positive, facultative intracellular, beta hemolytic, catalase positive
o Resistant to cold (refrigeration doesn’t matter), heat, pH changes
o “Tumbling motility” in liquid media
o Granulomatosis infantiseptica: 1st trimester = miscarriage; 3rd trimester = low birth weight, skin lesions, abscesses
o Listeriolysin O: membrane-damaging toxin
o “Actin rockets”

90
Q

Rickettsia Rickettsii

A

“Rocky Mountain Spotted Fever”
o Kansas to Virginia
o Centripetal rash (extremities to trunk) that involves palms and soles
o Gram negative, obligate intracellular
o Adheres to endothelial cells, escapes phagocytotic vacuole
o Host ATP and “exogenous factors” required for survival
o Ticks vector and reservoir

91
Q

Rickettsia Prowazeki

A
  • Brill-Zinsser disease, epidemic typhus
  • Centrifugal rash (trunk you extremities) that spares palms and soles
  • Vector = louse, reservoir = humans
  • “Recrudescent” disease: can lie dormant and be reactivated (think WWII soldier)
92
Q

Erlechia/Anaplasma

A
  • “Spotless spotted fever” - tick borne, similar to RMSF but no rash
  • Inclusion bodies (morulae) inside WBCs
  • Obligate intracellular
  • Biphasic life cycle (dense core cells, reticulate cells)
93
Q

Coxiella Burnetii

A
  • Q fever (sudden onset headache, fever, atypical pneumonia, granulomatous hepatitis, no rash)
  • Livestock (sheep, cattle, goats)
  • Not tick-borne
  • Endemic northern midwest (think Montana guy)
  • Obligate intracellular
  • Biphasic life cycle (small cell/large cell)
94
Q

Bartonella henselae

A
  • Gram negative, facultative intracellular, infect endothelial cells and erythrocytes (rare)
  • Cat scratch fever - axillary LN swelling
  • Bacillary angiomatosis in HIV+ patients (looks like Kaposi’s sarcoma)
95
Q

Bartonella quintana

A

“Trench fever”
• Gram negative, facultative intracellular
• Episodic ~5-day fever (“quintana”)
• Also bacillary angiomatosis, endocarditis, chronic lymphadenopathy
• Vector = louses, reservoir = humans
• WWI connection, now homeless
• Replicates in RBCs

96
Q

What medications can cause reactivation of latent TB

A

TNF-a inhibitors

97
Q

Mycobacteria virulence factors

A

Mycolic acid in cell wall (antigenic), ROS & reactive nitrogen species resistance, preventing macrophages from undergoing apoptosis (pH-mediated)

98
Q

Characteristics of latent mycobacterium patients

A

CXR negative, cultures negative, no symptoms, not infectious, not active disease, yet PPD positive

99
Q

What type hypersensitivity reaction is the PPD test?

A

Delayed (type IV) hypersensitivity

100
Q

“Atypical” but “TB-like” mycobacteria

A

M. kansasii, M. avian-intracellulare (MAC), M. scrofulaceum

101
Q

Mycobacterium TB endemic populations

A

Africa, homeless

102
Q

MDR mycobacterium endemic populations

A

Russia

103
Q

“Atypical” mycobacteria causing soft tissue infections

A
  • M. fortuitum (trauma/surgery, corneal infections, endocarditis)
  • M. marinum (“fish tank granuloma,” fresh/saltwater, swimming pools, aquariums)
  • M. ulcerans (ulcers, outside U.S.)
  • M. abscessus (“medical tourism” surgeries)
104
Q

What disease is associated with Mycobacterium avian Complex (MAC)?

A

AIDS

105
Q

Mycobacterium Leprae

A

Hansen’s disease:
• Painless, erythematous nodules
• Armadillos natural host
• Stain acid-fast but cultures negative
• Tuberculoid leprosy (Th1 mediated, lepromin positive, organisms on bx is rare, single lesion)
• Lepromatous leprosy (Th2 mediated, lepromin negative, organisms widely dispersed, multiple lesions)

106
Q

Treponema general virulence factors

A
  • No LOS
  • Hyaluronidase
  • Fibronectin coat (avoiding immune system)
  • Low antigen count (avoiding immune system)
107
Q

Treponema pallidum ssp. pallidum diagnosis

A

Syphilis:
• Darkfield microscopy
• Anti-cardiolipin Ab (non-specific, goes away with tx)
• Treponema Ab tests: MHA-TP, FTA-ABS (for life)

108
Q

Treponema pallidum ssp. pallidum stages/symptoms

A 
Syphilis:
• Primary: chancre (goes away)
• Secondary: bullseye rash (incl. palms and soles), lymphadenopathy, fever, gray coin-sized lesion in mouth
• Latent: asymptomatic
• Tertiary: CNS and organ involvement
109
Q

Treponema pallidum ssp. Endemicum

A

Bejel:
• Oral papules, lesions around edges of mouth (angular stomatitis), rhinopharyngitis mutilans
• Africa, asia, Australia
• Sharing utensils

110
Q

Treponema pallidum ssp. pertenue

A

Yaws:
• Various destructive lesions (keratosis, ulcers, scaling, shin problems d/t chronic osteitis)
• Africa, asia, South America
• Spread by direct contact

111
Q

Treponema caraterum

A

Pinta:
• Hyperpigmented/hypopigmented lesions lead to disfiguration
• South Americas
• Spread by direct contact

112
Q

Borrelia general characteristics

A
  • Spirochetes
  • Weakly gram negative
  • Giemsa or Wright stain
  • Antigenic variation in OMPs/Osps (bind factor H, avoid complement)
113
Q

Borrelia Burgdorferi

A

Lyme disease:
• Ticks in nymph stages
• Bullseye rash, headache, low-grade fever, develop progressive myalgia and arthralgia (can have neurons or cards manifestations later)
• Dx by history/sx, but also serology (ELISA, immunoblot - look for IgG to B. Burgdorferi)

114
Q

What bacteria cause relapsing fever? What are the potentially fatal sequelae?

A
  • Borrelia recurrentis: transmission by lice, single recurrence, deadly, uncommon in U.S.
  • Borrelia hermiis: transmission by ticks, multiple recurrence, less deadly, common in U.S.
  • Myocarditis (most common), cerebral hemorrhage, hepatic necrosis
115
Q

Leptospira interrogans

A

Leptospirosis:
• Spirochetes with bent/hooked ends
• Darkfield microscopy
• The “swimming in Hawaii” disease
• Transmission by urine of infected animal (rodents, dogs, cattle)
• 2 diseases: systemic (bacteremia, flu-like) and immune (no bacteremia, most severe form Weil’s disease)

116
Q

What type of virus is Hepadnaviridae according to the Baltimore system? Why is this important with regards to replication

A

Class VII, gapped DNA (non-enveloped dsDNA); it must use host DdDp in synthesis before RdRp to make new mRNA

117
Q

List steps of viral replication. Where does assembly occur for RNA and DNA viruses?

A

Adsorption, penetration, uncaring, synthesis, assembly, release; cytoplasm for RNA viruses and nucleus for DNA viruses

118
Q

Direct routes of viral transmission

A

Close contact, body secretions (feces, urine, spit, blood)

119
Q

Indirect routes of viral transmission

A

Utensils, medical instruments, needles, aerosol, vector, food/water, fomites

120
Q

Viral site of entry in alimentary tract

A

M cells between enterocytes

121
Q

How do viruses spread through the nervous system?

A

Against the direction of electrical impulse, using kinesins

122
Q

3 ways viruses spread through tissue

A

Entry, intracellular replication, bursting out the other side; transcytosis; infecting monocytes

123
Q

How do viruses evade CTLs?

A
  • Herpes blocks mitochondrial apoptotic pathway
  • Blocking proteosomal activity
  • Blocking TAP transfer of peptides to ER
  • Blocking MHC I formation
  • Blocking enzymes that load peptide onto MHC I
124
Q

Molliculites (mycoplasma) general characteristics

A
  • No cell wall
  • No peptidoglycan
  • No LPS
  • Sterols in membrane (osmotic resistance)
  • beta-Lactam abx resistance
125
Q

Mycoplasma pneumoniae virulence factors, symptoms and diagnosis

A
  • P1 adhesin - cytadherence
  • Ciliostasis (cilia stop beating)
  • H2O2 and CARDS = destruction of respiratory epithelia
  • Antigenic variation of surface proteins
  • Cold agglutinin (protein mimics RBCs, IgM forms against it)
  • Atypical pneumonia: cough, fever, anemia
  • Complement fixation or cold agglutinin
126
Q

Actinomyces

A
  • Gram positive, anaerobic, filamentous, rod-shaped
  • “Sulfur granules” in pus and tissue - look like grains of sand, granules contain bacteria
  • Poor oral hygiene and dental trauma
  • IUDs
127
Q

Nocardia

A
  • “Gardening injury” primary source is the soil (not part of normal flora)
  • Aerobic, filamentous, weakly gram +, mild acid fast
  • 3 types of infections: lung (N. asteroids, cavities, confluent bronchopneumonia), brain (disseminated abscesses may result from cavitary pulm disease), cutaneous (N. brasiliensis, superficial pustule, “mycetoma”)
128
Q

Bacterioides fragilis

A
  • Anaerobic, gram-negative rod
  • Common gram negative anaerobe from peritoneal infections (e.g. ruptured appendix)
  • Abscesses
  • Endogenous infections (normal flora)
129
Q

What component of fungal cell walls is recognized by antibodies?

A

Mannoprotein (antigenic)

130
Q

Different between fungal and mammalian cell membranes?

A

Fungi have ergosterol as opposed to cholesterol

131
Q

General fungal virulence factors

A
  • Adherence via ligands
  • Capsule (e.g. cryptococcus neoformans)
  • Avoiding phagocytosis
  • Dimorphism
  • Destructive enzymes
132
Q

3 types of diseases caused by fungi

A

Allergies (IgE mediated, fungi need not be viable), mycotoxicoses (Psychotropic ergot alkaloid produced by claviceps on grains, or Aflatoxin B1 produced by aspergillus flavus - hepatotoxic and carcinogenic), mycoses (fungal infections: superficial, cutaneous, subcutaneous, systemic)

133
Q

“True” fungal pathogens and endemic areas

A

Histoplasma: NE, midwest/southeast, west Texas
Blastomycoses: midwest, Great Lakes
Coccidioides: Southwest
Paracoccidioides: South America

134
Q

Conditions predisposing to opportunistic mycoses

A

Broad spectrum abx (esp to Candida), immunosuppressive drugs, cancer, radiation, AIDS, diabetes, neutropenia

135
Q

Opportunistic fungal pathogens and diseases

A

Candida: superficial and systemic, resistant to many anti-mycotics
Cryptococcus: CNS infection/meningitis, india ink for dx
Aspergillus: allergy, aspergilloma, aspergillosis
Pneumocystis (PCP): Pulmnoary exudates, AIDS association

136
Q

Mycoses microscopic tests

A

KOH, india ink (cryptococcus specific), wood lamp, Gomori’s, calcofluor

137
Q

Define mycelium

A

Mass of fungal filaments

138
Q

Malassezia furfur

A 
Pityriasis versicolor:
• Hypopigmented/hyperpigmented macule can appear anywhere
• PAS stain - "spaghetti and meatballs"
• Lipophilic - likes lipid medium
• Painless, may itch
• Not contagious
139
Q

Hortae werneckii

A

Tinea nigra
• Hyperpigmented macules on palms and soles
• Septate hyphae
• Not contagious

140
Q

Piedraia hortae

A

Black piedra

• Hard black gritty nodules on hair shaft

141
Q

Trichosporon beigelli

A

White piedra
• Soft white nodules on hair shaft
• Can lead to systemic and potentially fatal infection in immunocompromised

142
Q

Define dematiaceous

A

Pigmented/melanized fungi

143
Q

Tinea flavus

A

Scalp

144
Q

Tinea unguium

A

Nails (Onchomytosis)

145
Q

Microsporum Canis

A
  • Culture: creamy yellow/yellow-orange
  • Urease positive
  • Hair perforation test positive
  • Tinea capitis, tinea corporis
  • Kittens can transmit
146
Q

Epidermophyton floccosum

A
  • Tinea cruris & Tinea pedis
  • Hair perforation negative, urease positive
  • Slow colony growth
147
Q

Trichophyton Rubrum

A
  • “Ruby” = red on culture (in some capacity)
  • Urease negative
  • Hair perforation negative
  • Common cause of Majocchi’s granuloma: deep suppurative granulomatous inflammation (erythema, pustules, crusts and scaliness)
148
Q

Trichophyton Mentagrophytes

A
  • Hair perforation positive
  • Tinea pedis (military socks and closed toed shoes)
  • Can cause a lot of morbidities
149
Q

Sporotrichosis (Sporothrix schenckii)

A
  • “Rose handler’s disease” (or e.g. thorns, hay, etc)
  • Dimorphic: need to see cigar-shaped yeast and mold flowerettes for dx
  • Subcutaneous swelling follows lymphatics (~75%)
150
Q

Chromoblastomycosis

A
  • Dematiaceous fungi
  • Tropics
  • Verrucous lesions (later on = cauliflowerlike)
  • Medlar bodies (copper pennies), brownish “splitting” yeast cells
  • Muriform bodies
151
Q

(Eumycotic) mycetoma

A
  • Rare tropical disease (thanks)
  • Draining sinuses, granules in pus
  • Often in feet
  • Black grains in tissue
152
Q

6 virulence characteristics of viruses

A
  • Replication
  • Tropism
  • Invasiveness
  • Modify host defense
  • Enable virus to host
  • Intrinsic killing effects
153
Q

What viruses induce synctitium formation?

A

HIV, HSV-1, measles, RSV

154
Q

Viruses associated with cytokine storm? Which of these cytokines prevents viral replication?

A

Ebola, smallpox, influenza, COVID-19; Type I interferons (remember this is an example of positive feedback)

155
Q

Immune cell responsible for rash formation? For what viruses is this observed?

A

T cells (Th1), via IL-2 and IFN-gamma; measles, smallpox, VZV

156
Q

ADE of viral infections example

A

Dengue

157
Q

4 intestinal protozoa parasites

A

Entamoeba histiolytica (colon, liver inf secondary), Giardia lamblia (contaminated water, duodenum + diarrhea), Cryptosporidium parvum (only one dx’ed by acid-fast stool), Balantidium coli (ulcers in large intestine)

158
Q

The “brain eating amoeba” in southern water

A

Naegleria fowleri (remember it’s facultative)

159
Q

Plasmodium

A

Sporozoan, causes Malaria

160
Q

Trypanosome

A

Flagellate, causes African sleeping sickness/Chagas disease

161
Q

Naegleria, antamoeba

A

Amebic encephalitis, CNS infections

162
Q

Plasmodium falciparum

A

“A sporozoan that is less adapted to humans than other plasmodium species”

163
Q

Definitive host of a parasite is defined by

A

Host in which sexual reproduction occurs

164
Q

Ascaris

A

o Common in South America and tropical countries d/t poor water sanitation
o Someone has to have patent infection, has to leave stool on the ground
o Stool to soil to food to intestines (to lungs, systemically)

165
Q

Definitive host

A

Sexually mature parasite

166
Q

Paratenic host

A

Parasite arrested in stage of development

167
Q

Incidental host

A

Not the usual host but able to become parasitized

168
Q

Principal host

A

Host where parasite is most commonly found

169
Q

Intermediate host

A

Larva/asexually staged parasite

170
Q

Taenia

A

Tape worm:
• Also lives in pigs and cows
• Taeniasis: in our intestines (still “cysticerci”), we’re the definitive host (from pork)
• Cysticerosis: in our muscles, we’re the incidental host (from eggs)

171
Q

Anisakiasis

A
  • Sushi disease (but not in U.S.)
  • Humans incidental host
  • Fish paratenic host
  • Nematode
172
Q

Heartworm

A 
Dirofilaria immitis:
• Transmitted by mosquitos
• Humans incidental host
• Cats incidental host
• "Coin lesion" in lungs
173
Q

Main cell type(s) associated with protozoan parasites

A

Th1

174
Q

Main cell type(s) associated with helminths

A

Th2, eosinophils

Infectious Disease (Phase II) (2 decks)

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