Microbiology Superset RidEZ - Part 2 (1) Flashcards
1
Q
Disease states caused by Legionella (list only)
A
- Asymptomatic infection
- Pontiac fever
- Legionnaires disease
2
Q
Describe Pontiac fever
A
Caused by Legionella. Presents like influenza. Strikes suddenly and completely resolves in one week. Originally described in the Pontiac Michigan government AC.
3
Q
Describe Legionnaires’ disease
A
Very high fever with severe pneumonia
4
Q
Treatment for Legionella
A
Has a beta-lacatamase (penicillin-resistant)
- Erythromycin
- Rifampin
5
Q
Diagnosis: Pneumonia in a smoker >50 years of age. Gram stain of pus shows many neutrophils with few microbes.
A
Legionella
6
Q
Special culture requirements for: Legionella
A
Grows on charcoal yeast extract culture with iron and cysteine
Mnemonic: French legionnaire with silver helmet, sitting around a campfire (charcoal medium) with a canteen of water (water transmission) and his iron dagger-he is no sissy (cysteine).
7
Q
Legionella: Gram stain
A
Gram negative. Gram stains poorly (use silver stain)
Mnemonic: French legionnaire with silver helmet, sitting around a campfire (charcoal medium) with his iron dagger-he is no sissy (cysteine).
8
Q
Legionella: How transmitted?
A
Aerosol transmission from environmental water sources (AC, Showers, whirlpools, cooling towers, supermarket produce mist)
Mnemonic: French legionnaire with silver helmet, sitting around a campfire (charcoal medium) with a canteen of water (water transmission) and his iron dagger-he is no sissy (cysteine).
9
Q
Pseudomonas: Disease states
A
PSEUDDOburnnas
- Pneumonia (especially in CF)
- Sepsis (black lesions on skin)
- External otitis (swimmer’s ear)
- UTI (nosocomial and drug-resistant)
- Drug use
- Diabetic Osteomyelitis
- Burns and wound infections
- Hot tub folliculitis
10
Q
Pseudomonas: Organism characterization
A
- Gram-negative rod
- non-lactose fermenting
- Aerobic (think AERuginosa) and oxidase positive (cytochrome c oxidase for oxidative phosphorylation)
- Produces pyocyanin (blue-green) pigment
- Fruity odor
11
Q
What to know about exotoxins produced by: Pseudomonas aeruginosa
A
Exotoxin A is an ADP ribosylating A-B toxin (similar to Diphtheria toxin)
Mechanism: Inactivates elongation factor 2 (EF-2)
Also has endotoxin (as it is gram negative) which produces fever and shock.
12
Q
Diagnosis: Sepsis in burn victim
A
Most likely Pseudomonas
13
Q
Treatment for pseudomonas
A
Aminoglycoside
plus
Extended-spectrum penicillin (eg piperacillin, ticarcillin)
14
Q
Helicobacter pylori: Disease states
A
Causes:
- Gastritis
- 90% of duodenal ulcers
Risk factor for:
- Peptic ulcer
- Gastric carcinoma
15
Q
Helicobacter pylori: Characterization
A
- Gram negative rod
- Urease-positive
- Creates alkaline environment
16
Q
Treatment for Helicobacter Pylori
A
Triple treatment
- Metronidazole with one of the two combos below
$:
- Bismuth (eg Pepto-Bismol)
- Either Tetracycline or Amoxicillin
$$:
- Omeprazole
- Clarithromycin
17
Q
What bug?: Urease-positive gram-negative bacteria
A
Proteus and H. Pylori
18
Q
Zoonotic bacteria
A
- Borrelia burdorferi
- Francisella tularensis
- Yersinia pestis
- Pasteurella multocida
- Brucella spp. (Undulant fever from dairy/contact with animals)
Mnemonic: Bugs From Your Pet Undulate and Unpasteurized dairy gives you Undulant fever
19
Q
Borrelia burgdorferi: Disease states
A
Lyme disease
20
Q
Brucella: Disease states
A
Undulant fever/Brucellosis. Temperature slowly rises during day, peaks in the evening, and slowly declines to normal by morning.
Accompanied by other systemic symptoms.
21
Q
Brucella: Transmission
A
from animal contact (meat worker, farmer, veterinarian) or unpasteurized milk
22
Q
Gross mechanism of brucellosis
A
- Penetration of skin (but no buboes or primary skin ulcer), conjunctiva, lungs, GI tract
- Lymphatic spread
- Facultative intracellular growth in macrophages, and blood and organ invasion
23
Q
Francisella Tularensis: Disease states (list)
A
Tularemia, either:
- Pneumonic
- Oculoglandular
- Ulceroglandular
- Typhoidal
(Don’t POUT when you’ve got tularemia.)
24
Q
Describe Ulceroglandular tularemia
A
a. Well-demarcated hole in the skin with a black base
b. Fever and systemic symptoms
c. Swollen/red/painful purulent lymph nodes
Similar to plague, but with skin ulcer, and low mortality.
25
Francisella tularensis: Transmission
Most common: Handling of infected rabbits or from bites of ticks and deer flies
Hundred creatures in total all over US.
Mnemonic: Francis the rabbit is playing in the TULips, with a deerfly on one ear and a tick on the other.
26
Virulence of Francisella tularensis
Very. (10 organisms cause disease.)
27
Diagnosis of Francisella tularensis
Clinical picture, PPD-like skin test, and titers of Francisella Ig
28
Yersinia pestis: Transmission
PESTS like rats harbor the disease and fleas are the vector, biting the skin of humans. Found in campers, hunters, and hikers.
Mnemonic: A rat driving a fuel-injected (F1) VW bug (V and W antigens) fleeing (flea-ing) from a macrophage.
29
Fraction 1 (F1) antigen
Enables Yersinia pesitis to resist destruction after phagocytosis (facultative intracellular)
Mnemonic: A rat driving a fuel-injected (F1) VW bug (V and W antigens) fleeing (flea-ing) from a macrophage.
30
V antigen
Enables Yersinia pesitis to resist destruction after phagocytosis (facultative intracellular)
Mnemonic: A rat driving a fuel-injected (F1) VW bug (V and W antigens) fleeing (flea-ing) from a macrophage.
31
W antigen
Enables Yersinia pesitis to resist destruction after phagocytosis (facultative intracellular)
Mnemonic: A rat driving a fuel-injected (F1) VW bug (V and W antigens) fleeing (flea-ing) from a macrophage.
32
Yersinia pestis: Presentation in humans
1. Lymph node (usually inguinal [boubon is Greek for groin]) becomes inflamed (all four signs).
2. Fever, and headache.
3. Blackish discoloration under skin ("Black death")
33
Disease states caused by Yersinia pestis
Bubonic plague/pneumonic plague
34
Pasteurella Multocida: Transmission
Cat, dog, and animal bites. Also infects birds.
Mnemonic: Cat and dog chasing a bird in a "Pasteur".
35
T/F: All Zoonotic Gram negative bugs are facultative intracellular.
False. Pasteurella is not.
36
Pasteurella: Treatment
Do not suture wound after dog or cat bite/scratch. (Best breeding ground for Pasteurella)
Treat with penicillin or doxycycline.
37
Gardnerella: Characterization
Pleomorphic, gram-variable rod.
38
What disease states does Gardnernella cause?
Vaginosis
1. Greenish vaginal discharge with fishy smell
2. Noninflammatory (nonpainful)
3. Mobiluncus (anaerobe) is also seen
4. Clue cells are visible (vaginal epithelium covered with bacteria)
5. Positive Whiff test
39
Clue cell, indicative of Gardnerella vaginosis
What is this?
40
What does a positive PPD indicate?
1. Current infection
2. Past exposure
3. BCG vaccination
41
What does a negative PPD indicate?
1. No infection
2. Anergy (due to: steroids, immunocompromise, malnutrition), inject candida/mumps vaccine into other arm. If still negative, anergic.
42
Fast-fermenting lactose bacteria
Fast fermenters: (EEK! Too fast!)
1. E.coli
2. Enterobacter sp.
3. Klebsiella
43
Slow fermenting lactose bacteria
Slow fermenters:
1. Serratia
2. Citrobacter
3. "Others"
44
Tuberculosis infection: Gross mechanism
1. Inhaled aerosols from infected adults
2. Land in middle or lower lobes of lung (highest airflow) leading to small area of pneumonitis.
3. Bacteria enter macrophages, multiply, and spread hematogenously.
45
Mechanism of asymptomatic primary TB
1. Cell-mediated defense walls off foci of bacteria in caseous granulomas
2. Granulomas heal with fibrosis, calcification and scar formation
46
Difference between Ghon focus and Ghon complex
Ghon focus: Calcified tubercle in the middle or lower lung
Ghon complex: Ghon focus accompanied by perihilar or lobar lymph node calcified granulomas
47
What is a Ranke complex?
Same as a Ghon complex: Ghon focus accompanied by perihilar or lobar lymph node calcified granulomas
48
Mechanism of symptomatic primary TB
1. Large caseous granulomas develop in the lungs/other organs.
2. In the lungs, caseous material liquifies, is extruded out the bronchi and leaves cavitary lesions behind.
49
Mechanism of secondary Pulmonary TB
1. Infection occurs at apical areas of lung around the clavicles due to highest oxygen tension caused by decreased pulmonary circulation.
2. Infected areas grow, caseate, liquify and cavitate.
50
TB reactivation sites
1. Pulmonary (Lung parenchyma)
2. Pleura
3. Pericardium
4. Scrofula (Cervical lymph nodes: most common extrapulmonary site worldwide)
5. Kidney (Sterile pyuria)
6. Thoracic and lumbar spine (Pott's disease)
7. Chronic monoarthritis
8. CNS (subacute meningitis or parenchymal tuberculoma)
9. Miliary TB (Millet sized tubercles all over the body)
51
Tuberculosis rule of 5s
1. Droplet nuclei are 5 micrometers and contain 5 mycobacteria
2. 5% risk of reactivation in first 2 years and then 5% lifetime risk
3. Patients with HIV ("High five") have 5+5% yearly reactivation risk.
4. Induration measurements
a. HIV: >5 mm
b. High risk: >5+5 mm
c. Everyone else: >5+5+5 mm
52
Cause of Miliary tuberculosis
Severe bacteremia
53
Types of Mycobacteria and what they cause
Mnemonic: Identifying mycobacteria is no Light TASK
Mycobacterium
1. Leprae
2. Tuberculosis
3. Avium-intracellulare
4. Scrofulaceum
5. Kansasii
54
What disease state does Mycobacterium Avium-intracellulare cause?
bugs are multiple drug resistant and cause disseminated disease in AIDS
55
Symptoms of tuberculosis
1. Fever
2. Night sweats
3. Weight loss
4. Hemoptysis
56
Two Langhans type giant cells in which the nuclei are lined up around the periphery of the cell in a horseshoe pattern.
Seen in granulomatous conditions like TB
What is this?
57
What is Hansen's disease?
leprosy
58
What is leprosy caused by?
Mycobacterium leprae
59
Characterization and reservoir of Mycobacterium Leprae
1. Acid fast bacillus
2. Likes cool temperatures
3. Infects skin and superficial nerves
4. Cannot be grown invitro
5. Reservoir: Armadillos
60
Presentation of lepromatous leprosy
"Leonine facies"
1. Loss of eyebrows
2. Nasal collapse
3. Lumpy earlobe
61
Treatment for leprosy
Long-term oral dapsone
Alternative: Rifampin, clofazimine, and dapsone
62
Toxicity of longterm oral dapsone
1. Hemolysis
| 2. Methemoglobinemia
63
2 forms of leprosy
1. Lepromatous (Due to failed cell-mediated immunity. Lep. is Lethal)
2. Tuberculoid (self=limiting)
64
Rickettsiae: Characterization
Obligate intracellular parasites. Need CoA and NAD.
65
Rickettsiae: Transmission and presentation
Coxiella: Atypical. Transmitted by aerosol and causes pneumonia
All others: Arthropod vector causes classic triad of headache, fever and rash (vasculitis)
66
Treatment of Rickettsiae
Tetracycline
67
Difference between spread of rash in typhus and spotted fever
tyPHus is centriPHugal (moves outwards)
sPotted fever is centriPetal (moves inwards)
Both are caused by Rickettsiae
68
Which bug causes Rocky Mountain spotted fever?
Rickettsia rickettsii, transmitted by tick
69
Which bug causes endemic typhus?
Rickettsia typhi, transmitted by fleas
70
Which bug causes epidemic typhus?
Rickettsia prowazekii, transmitted by human body louse
71
Which bug causes typhus?
Endemic: Rickettsia typhi, transmitted by fleas
Epidemic: Rickettsia prowazekii, transmitted by human body louse
72
Which bug causes Q fever?
Coxiella burnetii, by inhaled aerosols from cowhide and placentas.
Remember: Carol Burnett coughing "Q" after inhaling spores from cowhide.
73
What separates Q fever from other rickettsial diseases?
Q fever is Queer. Rickettsial, but has an endospore, thus:
1. Caused by Coxiella burnetii (not called Rickettsia)
2. No rash
3. No vector (inhaled aerosols)
4. Negative Weil-Felix
5. Causative organism can survive outside for a long time.
74
Difference in tropism between Chlamydia and Rickettsia
Rickettsia: Endothelial cells of blood vessels
Chlamydia: Columnar epithelium
75
Where is the rash in Rocky Mountain spotted fever found?
Palms and soles, migrating to wrists, ankles, then trunk.
76
Where can rashes on the palms and soles of feet be seen?
1. Rocky mountain spotted fever
2. Syphilis
3. Coxsackie virus A infection (hand, foot, and mouth disease)
77
Weil-Felix reaction
Assays for antirickettsial antibodies, which cross-react with Proteus antigen
78
Typhus: positive or negative Weil-Felix
positive
79
Rocky mountain spotted fever: positive or negative Weil-Felix
positive
80
Q fever: positive or negative Weil-Felix
negative
81
What bug: Atypical walking pneumonia in prisoner or military recruit younger than 30
Mycoplasma pneumoniae
82
Describe mycoplasma pneumoniae pneumonia
1. Atypical walking pneumonia (insidious onset, headache, non productive cough, diffuse interstitial infiltrate)
2. X-ray looks worse than patient
3. High titer of cold agglutinins (IgM)
83
Special culture requirements for: Mycoplasma pneumoniae
Eaton's agar
84
Treatment for mycoplasma pneumoniae
Tetracycline or erythromycin.
Pencillin resistant because they have no cell wall.
85
Characterization of Mycoplasma pneumoniae
1. Facultative anaerobe with no cell wall (hence no gram stain)
2. Only bacterial membrane with cholesterol
3. High titer of cold agglutinins
4. Grown on Eaton's agar
86
True or False: No Gram-positive bugs have endotoxin.
False. Listeria monocytogenes has it.
87
Characterize Chlamydia
Obligate intracellular parasites
88
2 forms of chlamydia
1. Elementary body (small, dense) which Enters cell via endocytosis
2. Initial or Reticulate body, which Replicates In cell by fission
89
Disease states caused by Chlamydia trachomatis
1. Reactive arthritis (aka Reiter's syndrome)
2. Conjunctivitis
3. Non-gonococcal urethritis, cervicitis, and PID
90
Disease states caused by Chlamydia pneumoniae
Atypical pneumonia
91
Disease states caused by Chlamydia psittaci
Atypical pneumonia
92
Chlamydia species
1. Trachomatis
2. Pneumoniae
3. Psittaci
93
What is unusual about the chlamydial wall?
It lacks muramic acid.
94
Treatment of Chlamydia
Erythromycin or tetracycline
95
Reservoir for Chlamydia psittaci
Avian
96
Which chlamydia has an animal reservoir?
Psittaci: Avian
97
Lab diagnosis of chlamydia
Cytoplasmic inclusions seen on Giemsa or fluorescent-antibody stained smear
98
What disease is caused by Chlamydia Trachomatis serotypes A-C
1. Chronic infection
2. Blindness in Africa
Mnemonic: ABC: Africa, Blindness, Chronic infection
99
What disease is caused by Chlamydia Trachomatis serotypes D-K
1. Urethritis/PID
2. Ectopic pregnancy
3. Neonatal pneumonia
4. Neonatal conjunctivitis
100
What disease is caused by Chlamydia Trachomatis serotypes L1-L3
Lymphogranuloma venereum
1. acute lymphadenitis with a positive Frei test
2. ulcers
3. rectal strictures
Mnemonic: L1-3: Lymphogranuloma
101
Positive Frei test
Chlamydia Trachomatis serotypes L1-L3
102
Acquisition and treatment of neonatal conjunctivitis
Chlamydia trachomatis serotypes D-K acquired by passage through infected birth canal. Treat with erythromycin eye drops.
103
Characterization of spirochetes
Spiral-shaped bacteria with axial filaments
104
List of spirochetes
Mnemonic: BLT with spiral bacon
1. Borrelia (Big!)
2. Leptospira
3. Treponema
105
Visualization of Borrelia
Light microscopy with choice of aniline dye:
1. Wright's stain
2. Giemsa's stain
106
Stages of Lyme disease
1. Erythema chronicum migrans and flu-like symptoms
2. Neurologic and cardiac manifestations
3. Autoimmune migratory polyarthritis
107
Signs and symptoms of Lyme disease
Mnemonic: BAKE a Key Lime pie
1. Bell's palsy (and other CNS manifestations in Stage 2)
2. Arthritis (Autoimmune migratory in Stage 3)
3. Kardiac block (Stage 2)
4. Erythema chronicum migrans (Stage 1)
108
What species transmits Borrelia burgdorferi to humans?
Ixodes tick. Live o
109
Classic symptom of Lyme disease and which stage is it in?
Erythema chronicum migrans, an expanding "bull's eye" red rash with central clearing. Stage 1.
110
Animal reservoirs for borrelia burgdorferi
White-footed mouse and other small rodens, and the white-tailed deer. Ixodes tick picks up bugs from these animals and transmits them.
111
Most common setting for Borrelia burgdorferi infection
In the summer months in northeastern US (Lyme, CT)
112
What disease states does Treponema cause?
Treponema Pallidum causes syphilis.
Treponema Pertenue causes yaws (a non-STD tropical infection with positive VDRL)
113
What is yaws?
Treponema Pertenue causes yaws (a non-STD tropical infection with positive VDRL)
114
Presentation of primary syphilis
Painless chancre (localized disease)
115
What stage of syphilis: Painless chancre (localized disease)
Primary
116
Presentation of secondary syphilis
Disseminated disease with:
1. constitutional symptoms (fever, lymphadenopathy)
2. maculopapular rash (palms and soles)
3. condylomata lata
Mnemonic: Secondary means Systemic
117
What stage of syphilis: Disseminated disease with constitutional symptoms
Secondary syphilis
118
Presentation of tertiary syphilis
1. Gummas
2. Aortitis
3. Neurosyphilis (tabes dorsalis, general paresis)
4. Argyll Robertson pupil
119
What stage of syphilis: Gummas
tertiary syphilis
120
What stage of syphilis: Aortitis
tertiary syphilis
121
What stage of syphilis: Neurosyphilis (tabes dorsalis)
tertiary syphilis
122
What stage of syphilis: Argyll Robertson pupil
tertiary syphilis
123
What stage of syphilis: maculopapular rash (palms and soles)
Secondary syphilis
124
What stage of syphilis: condylomata lata
Secondary syphilis
125
Presentation of Congenital syphilis
1. Saber shins
2. Saddle nose
3. Deafness
126
What stage of syphilis: Saber shins
Congenital syphilis (not a stage)
127
What stage of syphilis: Saddle nose
Congenital syphilis (not a stage)
128
What stage of syphilis: Deafness
Congenital syphilis (not a stage)
129
Treatment for Syphilis
Penicillin G
130
Signs and symptoms of tertiary syphilis
1. Broad-based ataxia
2. Positive Romberg sign
3. Charcot joints
4. Stroke without hypertension
131
What is an Argyll-Robertson pupil?
Same as prostitute's pupil. Constricts with accommodation but is not reactive to light. Pathognomonic for tertiary syphilis.
132
What is the prostitute's pupil.
Same as Argyll-Robertson pupil. Constricts with accommodation but is not reactive to light. Pathognomonic for tertiary syphilis.
133
What is FTA-ABS used for?
FTA-ABS: Find the Antibody-Absolutely
1. Most specific for treponemes
2. Positive the earliest
3. Remains positive the longest
134
Interpret: Positive VDRL, Positive FTA
Active treponemal infection
135
Interpret: Positive VDRL, Negative FTA
Probably false positive
VDRL
1. Viruses (mono, hepatitis)
2. Drugs
3. Rheumatic fever and rheumatoid arthritis
4. Lupus and leprosy
136
Interpret: Negative VDRL, Positive FTA
Successfully treated treponemal infection
137
Sexuality of fungal spores
Asexual (mostly)
138
Which fungal infections are transmitted by inhalation of asexual spores?
1. Coccidioidomycosis
| 2. Histoplasmosis
139
What are conidia?
Asexual fungal spores
140
What disease states does Candida albicans cause?
1. Thrush esophagitis in immunocompromised patients (neonates, steroids, diabetes, AIDS)
2. endocarditis in IV drug users
3. vaginitis post-antibiotic use
4. diaper rash
5. Disseminated candidiasis to any organ
6. Chronic mucocutaneous candidiasis
141
Treatment for Candida Albicans infection
Superficial: Nystatin
Serious systemic: Amphotericin B
142
Histologic appearance of Candida Albicans
Budding yeast with pseudohyphae in culture at 20 degrees celsius
Germ tube formation at 37 degrees celsius
143
Candida albicans: Germ tube formation at 37 degrees celsius
What is this?
144
Candida albicans: Budding yeast with pseudohyphae in culture at 20 degrees celsius
What is this?
145
Which fungus causes thrush in immunocompromised
Candida albicans
146
Which fungus causes vulvovaginitis?
Candida albicans (high pH, diabetes, use of antibiotics)
147
Which fungus is endemic to Southwestern US?
Coccidioidomycosis
148
Which fungus is endemic to Mississippi and Ohio river valleys
Histoplasmosis
149
What fungus is this area known for: Southern Ohio
Histoplasmosis
150
What fungus is this area known for: Southern Illinois
Histoplasmosis
151
What fungus is this area known for: Missouri
Histoplasmosis
152
What fungus is this area known for: Kentucky
Histoplasmosis
153
What fungus is this area known for: Tennessee
Histoplasmosis
154
What fungus is this area known for: Arkansas
Histoplasmosis
155
What fungus is this area known for: Southern California
Coccidiomycosis
156
What fungus is this area known for: Southern Arizona
Coccidiomycosis
157
What fungus is this area known for: Mississippi river valley
Histoplasmosis (also Blastomycosis)
158
What fungus is this area known for: Ohio river valley
Histoplasmosis (also Blastomycosis)
159
What fungus is this area known for: Southwestern US
Coccidiomycosis
160
What fungus is this area known for: Rural Latin America
Paracoccidioidomycosis
161
What fungus is this area known for: Wisconsin
Blastomycosis
162
What fungus is this area known for: Minnesota
Blastomycosis
163
Spherule filled with endospores in coccidioidomycosis
What is this?
164
Characterize histoplasmosis histologically
Tiny yeast inside macrophages. Thin cell wall with no true capsule.
165
What is the vector for histoplasmosis?
Bird or bat droppings
166
What do bird and bat droppings carry?
Histoplasmosis
167
histoplasmosis showing intracellular organisms in bone marrow macrophages
What is this?
168
Paracoccidioidomycosis (captain's wheel appearance)
What is this?
169
Blastomycosis (Big, Broad-Based Budding)
What is this?
170
What characterizes dimorphic fungi?
Mold in soil (lower temperature) and yeast in tissue (body temperature)
Mnemonic: Cold is mold, heat is yeast
171
List the dimorphic fungi
Histoplasmosis, Blastomycosis, and Paracoccidioidomycosis (but not coccidioidomycosis which is a spherule in tissue)
172
Treatment for coccidiomycosis
Local: Fluconazole or ketoconazole
Systemic: Amphotericin B
173
Treatment for paracoccidiomycosis
Local: Fluconazole or ketoconazole
Systemic: Amphotericin B
174
Treatment for Histoplasmosis
Local: Fluconazole or ketoconazole
Systemic: Amphotericin B
175
Treatment for Blastomycosis
Local: Fluconazole or ketoconazole
Systemic: Amphotericin B
176
What is cultured on Sabouraud's agar?
Fungi (specifically dimorphic fungi)
177
What disease state does Malassezia furfur cause?
Tinea versicolor: Hypopigmented skin lesions which occur in hot humid weather.
178
Treatment for Tinea versicolor
Topical miconazole or selenium sulfide (Selsun)
179
What resembles spaghetti and meatballs histologically?
combination of mycelium strands and numerous spores of Malassezia furfur in KOH prep
180
What disease state does Cladosporium werneckii cause?
Tinea nigra: Infection of keratinized layer of skin. Appears as brownish spot.
181
What causes Tinea versicolor?
Malassezia furfur
182
What causes Tinea nigra?
Cladosporium werneckii
183
Treatment for Tinea nigra
topical salicylic acid
184
What are the common dermatophytes and what do they cause?
Microsporum, Trichophyton, and Epidermophyton
cause all the tineas except for versicolor and nigra
185
What causes Tinea corporis?
Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
186
What causes Tinea cruris?
Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
187
What causes Tinea pedis?
Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
188
What causes Tinea capitis?
Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
189
What causes Tinea unguium?
AKA Tinea onychomycosis.
Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
190
What causes Tinea onychomycosis?
AKA Tinea unguium.
Dermatophytes (such as Microsporum, Trichophyton, and Epidermophyton)
191
How does Tinea corporis present?
Ring shape with a red raised border
192
How does Tinea cruris present?
AKA jock itch
Itchy red patches on groin and scrotum
193
How does Tinea capitis present?
Scaling on the scalp
194
How does Tinea unguium/onychomycosis present?
Nails are thickened discolored and brittle
195
Lab diagnosis of dermatophyte infection
1. Dissolve skin scrapings in KOH, which digests the keratin. Microscopic examination reveals branched hyphae.
2. Direct examination of skin with Wood's light (UV light at 365 nm wavelength) will fuoresce green if Microsporum.
196
Treatment for dermatophyte infection
1. Topical imidazoles
| 2. Oral griseofulvin (Tinea capitus and tinea unguium)
197
What causes a fungus ball?
Aspergillus
198
What disease states does Aspergillus cause?
1. Allergic bronchopulmonary aspergillosis
2. Lung cavity aspergilloma
3. Invasive aspergillosis
199
Histologic appearance of aspergillus
Mold (not dimorphic) with septate hyphae that branch at a V-shaped (45 degree) angle). Rare fruiting bodies.
200
Aspergillus (septate hyphae branching at 45 degrees with fruiting bodies)
What is this?
201
What disease states does cryptococcus neoformans cause?
1. Cryptococcal meningitis
| 2. Cryptococcosis
202
Histologic appearance of cryptococcus neoformans
5-10 micrometer yeasts with wide capsular halo. Narrow based unequal budding.
203
How is cryptococcus neoformans stained?
1. India ink
| 2. Latex agglutination test for polysaccharide capsular antigen
204
Where is cryptococcus neoformans found?
Soil and pigeon droppings.
