Micro Flashcards
1
Q
How do you culture H. flu?
A
Chocolate agar with factors V (NAD+) and X (hematin)
2
Q
How do you culture N. gonorrhoeae and N. meningitidis?
A
Thayer-Martin (or VPN) media –> Vancomycin + Polymyxin, and Nystatin
3
Q
How do you culture B. pertussis?
A
Bordet-Gengou agar (potato)
4
Q
How do you culture C. diptheriae?
A
Tellurite agar, Loffler medium
5
Q
How do you culture M. tuberculosis?
A
Lowenstein-Jensen agar
6
Q
How do you culture M. pneumoniae?
A
Eaton agar - requires cholesterol
7
Q
How do you culture lactose-fermenting enterics?
A
Pink colonies on MacConkey agar. E. coli also grown on EMB as shiny green colonies.
8
Q
How do you culture Legionella?
A
Charcoal yeast extract agar buffered with cysteine and iron
9
Q
How do you culture fungi?
A
Sabouraud agar
10
Q
What bug has yellow granules?
A
Actinomyces israelii – yellow “sulfur” granules composed of filaments of bacteria
11
Q
What bug has yellow pigment (not granules)?
A
Staph. aureus (aureus means “gold”)
12
Q
What bug has green pigment?
A
Pseudomonas aeruginosa
13
Q
What bug has red pigment?
A
Serratia marcescens (think” maraschino cherries”)
14
Q
Which bacterial capsule contains D-glutamate instead of polysaccharide?
A
Bacillus anthracis
15
Q
What bugs stain with Giemsa stain?
A
Chlamydia, Borrelia, Rickettsiae, Trypanosomes, Plasmodium
16
Q
What does PAS stain for, and what bugs are positive?
A
Stains glycogen - Whipple disease (Tropheryma whipplei)
17
Q
What does the Ziehl-Neelsen stain stain?
A
Acid-fast organisms - Norcardia, mycobacterium
18
Q
What bugs show up on silver stain?
A
Fungi, Legionella, and H. pylori
19
Q
What group of bacteria generally have a foul smell?
A
Obligate anaerobes - lack catalase or superoxide dismutase. Aminoglycosides are ineffective
20
Q
What is Protein A?
A
Binds Fc region of IgG - prevents opsonization & phagocytosis. Staph aureus.
21
Q
What is M protein?
A
Helps prevent phagocytosis –> in group A streptococcus
22
Q
What does diptheria toxin do?
A
Inactivates EF-2 (no more protein synthesis)
23
Q
What is Exotoxin A?
A
Pseudomonas aeruginosa toxin : Inhibits EF-2
24
Q
What do Shiga and Shiga-like toxin do?
A
Inactivate 60S ribosome by removing adenine from rRNA
25
What does ETEC heat-labile toxin do?
Overactivates adenylate cyclase to increase cAMP and increase Cl- secretion into gut
26
What does ETEC heat-stable toxin do?
Overactivates guanylate cyclase to increase cGMP and decrease reabsorption of NaCl and water in the gut (Labile in Air, Stable on Ground)
27
What bug has edema factor, and what does it do?
Bacillus anthracis - mimics adenylate cyclase enzyme to increase cAMP (responsible for edematous borders of black eschar)
28
What does cholera toxin do?
Overactivates adenylate cyclase (increase cAMP) by permanently activating Gs --> increased Cl- secretion and H2O efflux
29
What does pertussis toxin do?
Overactivates adenylate cyclase (inc cAMP) by disabling Gi - impairs phagocytosis to permit microbe survival
30
What does Tetanospasmin do?
Cleaves SNARE proteins responsible for GABA and glycine release (from Renshaw cells in spinal cord)
31
What does botulinum toxin do?
Cleaves SNARE proteins responsible for ACh release
32
What bug has alpha toxin, and what does it do?
Clostridium perfringens - Phospholipase (lecithinase) that degrades tissue and cell membranes --> myonecrosis and gas gangrene
33
What bug has streptolysin O, and what does it do?
Streptococcus pyogenes - Protein that degrades cell membrane --> lyses RBCs (contributes to B-hemolysis)
34
What does TSST-1 do?
Brings MHC II and TCR in proximity to outside of antigen-binding site to cause overwhelming release of IFN-gamma and IL-2
35
What second bug has Exotoxin A, and what does it do?
Streptococcus pyogenes - Brings MHC II and TCR in proximity to outside of antigen-binding site to cause overwhelming release of IFN-gamma and IL-2 (superantigen)
36
What does Endotoxin cause?
Edema, Nitric Oxide, DIC/Death, Outer Membrane, TNF-alpha, O-antigen, eXtremely heat stable, IL-1, Neutrophil chemotaxis
37
Which bacterial toxins are encoded in a lysogenic phage?
ABCDE: ShigA-like toxin, Botulinum toxin, Cholera toxin, Diptheria toxin, Erythrogenic toxin of Strep pyogenes
38
Word association: Novobiocin resistant?
Staph saprophyticus
39
What two bugs are distinguished by sensitivity to Bacitracin?
S. pyogenes is sensitive, S. agalactiae is resistant (both B-hemolytic)
40
What is used to distinguish gamma-hemolytic strep species?
Group D/ enterococcus can grow in bile and 6.5% NaCl.
| Nonenterococcus (strep bovis) cannot.
41
Optochin sensitivity distinguished between which bugs?
Alpha-hemolytic strep:
S. pneumo is optochin sensitive (and bile soluble)
Viridans strep is Optochin resistant (and bile insoluble)
42
Which bugs are B-hemolytic?
Staph aureus, Strep pyogenes, Strep agalactiae, Listeria
43
What the bleep is S. sanguinis???
Part of Viridans group Strep - makes dextrans which bind fibrin-platelet aggregates on damaged heart valves --> endocarditis. Dental caries are Strep
44
How does Rheumatic fever originate?
Antibodies to M protein of GAS. ASO detects recent infection. (Jones criteria - joints, heart, nodules (subQ), erythema, syndenham chorea)
45
With Group A strep, is impetigo more common before pharyngitis or glomerulonephritis?
glomerulonephritis
46
Which bug is Hippurate test +?
Strep agalactiae (also has CAMP factor that helps in hemolysis)
47
What are Lancefield antigens based on?
Differences in the C carbohydrate on strep bacterial cell wall (D includes enterococci)
48
What bacteria shows gram positive rods with metachromatic (blue and red) granules?
Crynebacterium diptheriae (club-shaped)
49
What do spores have in their core?
Dipicolinic acid (autoclave to kill spores)
50
What bug (and toxin) cause reheated rice syndrome?
Bacillus cereus - toxin is cereulide (preformed)
51
How does Listeria evade the immune system?
Forms "rocket tails" via actin polymerization --> moce through cytoplasm and into cell membrane to avoid antibody (tumbling motility)
52
What is the only gram-positive organism to produce LPS?
Listeria
53
What bug often causes oral/facial abscesses?
Actinomyces
54
What bacteria resemble fungi?
Actinomyces and Nocardia
55
What is cord factor?
In mycobacteria - inhibits macrophage maturation and induces release of TNF-alpha. *Sulfatides (surface glycolipids) inhibit phagolysosome fusion.
56
Lepromatous vs. Tuberculoid leprosy: what types of immune response predominates?
Lepromatous - Th2
Tuberculoid - Th1
*Leprosy likes cold parts of body (stocking/glove)
57
How do you differentiate the oxidase +, gram -, comma-shaped rods?
C. jejuni - grows at 42 C
V. cholerae - Grows in alkaline media
H. pylori - produces urease
58
Which bug produces B-galactosidase?
E. coli --> breaks lactose into glucose and galactose
59
What large group of bugs are resistant to Pen G and vanc but not penicillin derivatives?
Gram negatives - outer membrane inhibits entry of pen G and vancomycin
60
What is used to prevent neonatal transmission of gonorrhoea?
Erythromycin ointment
61
What should you use to treat mucosal infections of H. flu?
Amoxicillin and clavulanate. Ceftriaxone for meningitis
62
Which bug is detected by presence of antigen in the urine?
Legionella (treat wiht macrolide or quinolone)
63
What is Pontiac Fever?
Mild flu-like syndrome from Legionella
64
Chronic pseudomonas pneumonia in a CF patient is associated with what?
Biofilms
65
What is ecthyma gangrenosum?
Ulcerous lesions from pseudomonas
66
What is unique about EPEC?
Common for diarrhea in Pediatrics (Prevents absorption by adhering to apical surface)
67
Which E. coli does NOT ferment sorbitol?
EHEC
68
What special groups are associated with Klebsiella?
Diabetics and Alcoholics
69
Which GI bug is notable for producing hydrogen sulfide?
Salmonella (also, antibiotics may prolong fecal excretion of organism)
70
Salmonella vs Shigella: what types of cells respond?
Salmonella - monocytic response
| Shigella - PMN infiltrate
71
Which bug causes mesenteric adenitis that can mimic Crohn's or appendicitis?
Yersinia entercolitica (from pet feces, contaminated milk, or pork)
72
Name the spirochetes.
Borrelia, Leptospira, Treponema (BLT)
73
Tell me about Leptospira interrogans.
From water contaminated with animal urine (surfers and in tropics) - flu-like symptoms w/ jaundice, photophobia, and conjunctival suffusion. Weil disease is severe form w/ azotemia from liver and kidney dysfxn.
74
What bug causes Lyme disease?
Borrelia burgdorferi (Ixodes tick)
75
When does transmission of congenital syphilis normally occur?
After the first trimester
76
What are some causes of false positives on VDRL testing?
Viruses (mono, hepatitis), Drugs, Rheumatic Fever, Lupus and Leprosy (VDRL)
77
What causes relapsing fever?
Borrelia recurrentis (transmitted by louse)
78
What infection is assocaited with aerosols of cattle/sheep amniotic fluid?
Q Fever from Coxiella burnetii
79
What insect caries Rickettsia rickettsii
Dermacentor ticks
80
Clue cells are associated with what infection?
Gardnerella vaginalis - associated with sexual activity, but not sexually transmitted. Overgrowth of anaerobic bacteria in the vagina.
81
What is the treatment for all Rickettsia and vector-borne illnesses?
Doxycycline
82
Where dose RMSF rash start?
Wrist and ankles
83
What infections have morulae, and how do you distinguish between them?
Ehrlichiosis - morulae (berry-like inclusions) in monocytes
| Anaplasma - morulae in granulocytes
84
How does one catch Q fever?
Tick feces and cattle placenta release Coxiella spores
85
What makes the chlamydial cell wall special?
Lacks muramic acid
86
What do Chlamydia trachomatis Types A,B, and C cause?
Chronic infection and blindness due to follicular conjunctivitis in Africa (Africa/Blindness/Chronic)
87
What infection has a high titer of cold agglutinins?
Mycoplasma pneumonia
88
What has budding yeast with "captain's wheel" formation?
Paracoccidioidomycosis - in Latin America
89
Latex agglutination test detects which bug?
Cryptococcus neoformans (fungus)
90
Mucormycosis and rhizopus especially like which patients?
Ketoacidotic diabetic and leukemic patients --> penetrate cribriform plate (irregular, broad, nonseptate hyphae branching at wide angles)
91
What are "cigar-shaped budding yeast"?
Sporothrix schenkii - treat with potassium iodid ("rose in the pot")
92
What bug has a "Maltese cross" on blood smear?
Babesia (parasite) - also can have ring form. Carried by Ixodes tick. Fever and hemolytic anemia in NE US.
93
What are the signs of visceral leishmaniasis?
(Kala-azar) - spiking fevers, hepatosplenomegaly, pancytopenia. Transmitted by sandfly. macrophages contain amastigotes.
94
Which parasite cannot live outside a human b/c it cannot form cysts?
Trichomonas (strawberry cervix)
95
Tell me about Onchocerca volvulus.
A parasite transmitted by the female blackfly. Causes hyperpigmented skin and river blindness (black flies, black skin nodules, black sight) Allergic reaction to microfilaria possible. Treat w/ Ivermectin
96
What it loa loa?
Parasite - deer/horse/mango fly. Swelling skin, worm in conjunctiva. Diethylcarbamazine.
97
What bug causes visceral larva migrans?
Toxocara canis --> Bendazoles
98
What drug to treat most tapeworms and flukes?
Praziquantel (bendazole for neurocysticercosis)
99
What is Diphyllobothrium latum?
Parasite from ingesting raw fish - competes for vit B12 in gut --> anemia
100
Which parasite causes hydatid cysts in the liver?
Echinococcus granulosus - ingestion of eggs from dog feces
101
What is clonorchis sinensis?
Parasite from undercooked fish - biliary tract inflammation --> pigmented gallstones. Associated with cholangiocarcinoma.
102
Which DNA viruses are circular?
Papilloma, polyoma, and hepadna
103
All viruses are single-stranded except for which?
Reoviridae
104
Which is the only DNA virus that does not replicate in the nucleus?
Poxvirus
105
What are the other names for HHV-3, HHV-4, and HHV-5?
3-VZV, 4-EBV, 5-CMV
106
Which virus family is Hep B?
Hepadna
107
Which virus causes pink eye?
Adenovirus. Also febrile pharyngitis, acute hemorrhagic cystitis, pneumonia
108
What virus family do JC and BK viruses belong to?
Polyomavirus
109
JC virus causes what?
Progressive multifocal leukoencephaly
110
BK virus normally infects whom?
Transplant patients (esp kidney)
111
Molluscum contagiosum belongs to what virus family?
Poxvirus
112
Single "owl eye" in a cell makes you think of what?
CMV
113
Hep A belongs to what virus family?
Picornavirus
114
Norovirus is from what virus family?
calicivirus
115
HCV is from what virus famaily?
Flavivirus (so is Yellow fever, dengue, St. Louis encephalitis, and West Nile)
116
What are the togaviruses?
Rubella, Eastern and Western equine viruses
117
What causes croup?
parainfluenza
118
Waht are the Filoviruses?
Ebola/Marburg hemorrhagic fever - often fatal
119
What are the arenaviruses?
LCMV, Lassa fever encephalitis (from mice)
120
What are the bunyaviruses?
CAlifornia, Sandfly/rift fever, Crimena-Congo, Hantavirus
121
What is special about picornaviruses in terms of protein production?
Production of one large polypeptide that is cleaved
122
HDV is from what virus family?
RNA delta virus
123
What are the functions of gp120, gp41, gp24, and pol?
gp120- Docking glycoprotein
gp41- Fusion and entry
p24(gag)- capsid protein
pol- reverse transcriptase, aspartate protease, integrase
124
Bacillary angiomatosis in HIV is caused by what?
BArtonella henselae
125
Waht is the main bug that causes retinitis in HIV?
CMV
126
What is the dominant normal flora of the vagina?
Lactobacillus
127
What is the reservoir for shigella?
Humans only
128
Motility of which bug causes "swarming" on agar?
Proteus mirabilis - UTI; assciated with struvite stones
129
How does roseola present?
Macular rash appears after several days of high fever. Can have febrile seizures.
130
Koplik spots associated with which childhood infection?
Measles
131
What bug causes scarlet fever?
Strep pyogenes (A)
132
What causes chancroid?
Haemophilus ducreyi - painful
133
What is Fitz-Hugh-Curtis?
infection of liver capsule from PID causing "violin string" adhesions
134
What bugs are not covered by Cephalosporins?
LAME: Listeria, Atypicals, MRSA, and enterococci
135
What are imipenem administered with?
Cilastatin to decrease inactivation of drug in renal tubules.
