Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

01. Step 1 mine > Microbiology 1 > Flashcards

Microbiology 1 Flashcards

1
Q

Two selective gene mutations responsible for Isoniazid resistance

A
  1. Decrease in bacterial EXPRESSION of catalase-peroxidase enzyme (required por ISZ activation)
  2. Modification of the protein target binding site for ISZ.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When is the only acceptable case where Isoniazid can be used as monotherapy?

A

Patients with
+ PPD
- chest X-ray
(like me - no evidence of clinical disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

In which areas can Isoniazid reach therapeutic levels?

A
  • Within macrophages
  • Areas of caseous necrosis
  • Cerebrospinal Fluid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Erythema infectiosum (5th disease) is caused by

A

Parvovirus B19

single-stranded DNA virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The “slapped-cheek” rash develops in ____________ AFTER the symptoms have resolved

A

Parvovirus B19

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The lacy, reticular rash in Parvovirus B19 (erythema infectiosum) results from___________

A

Immune complex deposition

timing coincides with increasing IgM and IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Parvovirus B19 (from Erythema infectiosum - 5th disease) replicates in ____________

A

Erythrocyte precursors in the bone marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Cellular receptor for Parvovirus B19 in erythrocyte precursors

A 
P antigen (globoside) 
- cellular receptor for Parvovirus B19
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Patient with sickle cell disease that presents generalized malaise followed by lace-like rash. Develops aplastic anemia.
Infection responsible for these symptoms:

A

Parvovirus B19 (Erythema infectiosum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q 
Nonspecific prodrome (malaise, fever, congestion)
\+ 
Slapped-cheek 
\+ 
Lacy, reticular body rash
A

Erythema infectiosum (Parvovirus B19)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Hepatitis E virus type

A

Hep E

  • UnEnveloped
  • Single-stranded RNA
  • Spreads through fecal-oral route
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Most concerning feature of hepatitis E infection

A

High mortality rate in infected prEgnant women

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

If there is a case of fulminant hepatitis in pregnant women in Asia, Sub-saharan Africa or Mexico, you think about

A

Hep E infection (PrEgnant)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Is Hep E associated with chronic liver disease or carried state?

A

NO. with neither

Hep E is self-limited.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In Hep E infection, HEV Ag and HEV RNA are detected in:

a) earliest stages (asymptomatic)
b) early stages (symptomatic)
c) late stages (symptomatic)
d) Resolved

A

In Hep E, HEV Ag and HEV RNA are detected in:

a) Earliest stages (asymptomatic patient)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

If we see serum transaminases and IgM anti-HEV titers rise + clinical illness, we think of:

A

Late stages of Hep E infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Blastomyces dermatitidis is a:

A

dimorphic fungus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Blastomyces dermatitidis causes infection in: _________ people

A

Immunocompetent people

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Endemic area of Blastomyces dermatitidis

A

Mississippi, Ohio

(found in mold, soil, dogs, horses) = farm!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Transmission route of Blastomyces dermatitidis:

A

Respiratory —> lungs —-> Yeast (thermal dimorphism)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Diseases that Blastomyces dermatitidis infection can mimic:

A
  • Community-acquired pneumonia (resolves spontaneously)

- Chronic pneumonia (like TB, other fungi or cancer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Findings in pulmonary blastomycosis (Blastomyces dermatitidis)

A
  • Granuloma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When can we see EXTRAPULMONARY findings in patients with blastomycosis (Blastomyces dermatitidis)

A

Immunocompromised patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Round yeast with thick walls and broad-based budding

A

Blastomyces dermatitidis (she thick AF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Preferred treatment for Blastomycosis (Blastomyces dermatitidis)

A

Itraconazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Farmer from Mississippi or Ohio that resembles TB or pneumonia but who is immunocompetent (no HIV)

A

Blastomycosis (Blastomyces dermatitidis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Hepatitis A is a ______ ________virus with an average incubation of ______ days

A

Hep A RNA picornavirus

incubation 30 days.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Transmission of Hep A

A

Fecal-oral (overcrowding and poor sanitation - think shitty cafeterias)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Hep A outbreaks result from:

A
  • Contaminated water or food

- Shellfish (raw or steamed) !!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Patient who ate seafood or ate in the last month or so in a shitty cafeteria + usually smokes but does not want to smoke anymore

A

Hep A infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Aversion to smoking + malaise, fatigue, anorexia, nausea, vomiting, mild abdominal pain

A

Hep A infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Is hepatomegaly seen in Hepatitis A?

A

Hell yeah

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What spikes early in Hep A and what increases later?

a) serum AminoTransferases
b) Billirubin
c) Alkaline phosphatase

A

Hep A first spike:

  1. AminoTransferases
  2. Bilirrubin and Alkaline Phosphatase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Marker or active Hep A disease

A

Anti-HAV IgM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Does Hep A progress to chronic-hepatitis or cirrhosis or risk of hepatocellular carcinoma?

A

Nah bro.

Hep A is self-limited and pretty chill

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Light microscopy, budding yeasts with pseudohyphae

A

(picture) of light microscopy Candida fungi yeast (single cell) form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Test specific to distinguish Candida albicans from other candida species

A

Germ tube test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Inoculation of ________ _________ into serum at 37ºC for 3 hours leads to formation of hyphae from yeast. This test is called ______ _______ test

A

Candida albicans 37ºC for 3 hrs = germ tube test (diagnostic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

In immunocompromised patients, Candida can cause:

A

Disseminated disease that affects every organ system (preumonia, esophagitis, right-sided endocarditis, abcesses and candidemia sepsis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Most common cause of opportunistic mycosis

A

Candida albicans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

CSF findings:

  • Pleocytosis (elevated leukocyte count) w/left shift
  • Elevated protein
  • Low-normal glucose
A

Bacterial meningitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Facultative intracellular (grows in macrophages), gram positive rod with flagellar-based tumbling motility

A

Listeria monocytogenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Gram positive rod that can multiply in cold temperatures 4-10ºC (unpasteurized milk, milk products, raw meat, unwashed fruits and vegetables)
- Infects immunocompromised adults more often.

A

Listeria monocytogenes

Meningitis in immunocompromised adults, can also be delivered transplacentally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Antibiotic of choice for Listeria

A

Ampicillin

ListeriA
m
p
i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Q fever

A

Coxiella burnetti

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Coxiella burnetti infection occurs by:

A

Inhalation of bacteria from air contaminated from animal waste (farms - waste from cattle and sheep)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Acute Q fever (Coxiella burnetti) presentation:

A
  • Nonspecific febrile illness >10 days
  • Fatigue, myalgias
  • Severe debilitating headaches (retroorbital) + photophobia
  • Pneumonia (lobar consolidation)
  • Increased liver enzymes
  • Thrombocytopenia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Chronic Q fever (Coxiella burnetti)

A

Fatal if untreated

- infective endocarditis in patients with valve disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

If a lot of people begin having severe nausea and vomiting after a picnic or potluck where there was egg and mayo salad, you immediately think in:

A

Enterotoxigenic Staph aureus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Pathologic mechanism of foodbourne illness where the person ingests a preformed enterotoxin

A

Staph aureus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Pathologic mechanism of foodbourne illness where person has enterotoxin made in their intestine

A
  • Clostridium perfringens
  • ETE.C - STE.C
  • Vibrio cholerae
    (> 1 day onset / Watery-bloody diarrhea)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Clinical manifestations of ingestion of heat-stable enterotoxin (vomiting, nausea, abd cramping) occur with:

A
  • Staph aureus (mayo, egg, chicken)

- Bacillus cereus (rice - reheated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Tzank smear (picture)

A

Multinucleated giant cells in HSV (Herpes Simplex Virus) infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What is the difference in a Tzank smear between HSV (Herpes Simplex Virus) and Varicella-Zoster virus (VZV) infection?

A

There is no difference in their Tzank smears

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Primary infection with HSV-1

A

Gingivostomatitis

Painful vesicles that cover lips and gingiva, may appear in palate and oropharynx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Primary reason for hospitalization in primary infection with HSV-1

A

Dehydration (2ndary to pain in gingivostomatitis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Difference between HSV-1 primary infection and reactivation of latent herpes infection clinical manifestations

A

In primary HSV-1, a very painful gingivostomatitis arises + systemic symptoms (fever, malaise)

In reactivation of latent herpes infection in TRIGEMINAL ganglia = only mild, perioral vesicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Enveloped RNA virus that does NOT contain a replicase or RNA polymerase

A

Hep D virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Hep D virus can only finish its replication cycle in the setting of coinfection with:

A

Hep B virus

B+D Big Dick

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Fulminant viral hepatitis can occur in these types of Hepatitis Viruses:

A

All of them A,B,C,D,E

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Hepatocellular carcinoma is most commonly associated with Hep ____ infection

A

Hepatitis C or B = HeBatocellular Carcinoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Autoclave machines work at a minimum of ____°C

A

134 °C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Lower temperatures in autoclave (less than 134 °C) can lead to _______-______ bacteria to develop.

A

Spore-forming bacteria (Bacillus and Clostridium) - only survive up to 120 °C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Common pathogenic spore-forming bacteria

A

Clostridium and Bacillus

C. perfringens, C. botulinum, Bacillus anthracis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

If a patient has:
Positive Anti-Hbs
Negative Anti-HBc IgG
What is the best diagnosis?

A

Has been vaccinated against Hep B virus

presence of Anti-HBs but NOT Anti-HBc IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

In contrast to the vaccine, which only includes HBsAg, infection with Hep B virus exposes patients to additional antigens, such as:

A

Hepatitis B core antigen (HBcAg) which is found in the virus but not in the vaccine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Patient who had a Hep B infection but is now recovered will show signs of these two antigens on serum:

A
  1. Anti-HBsAg

2. Anti-HBcAg (important in infected individuals!)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Bacterial meningitis in ADULTS in most commonly caused by:

A
  1. Streptococcus pneumoniae

2. Neisseria meningitidis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Bacterial meningitis triad

A
  • HIGH fever (more than 38°C)
  • Stiff neck (pain)
  • Altered level of consciousness
  • Generalized headache
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Next step in management after patient presents with signs and symptoms of meningitis and has already undergone a noncontrast CT scan of the head with no abnormalities

A

Lumbar puncture

+ blood culture, + empiric antibiotics + LP with CSF analysis for abx sensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q 
Streptococcus gallolyticus (S bovis) - nonenterococcal group D streptococci 
mainly causes:
A

SBE - Subacute Bacterial Endocarditis

similar to S viridans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Bacteremia or endocarditis caused by S gallolyticus is associated with this other disease:

A

Colonic cancer (25% cases)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

Most common organism causing bacteremia (+sepsis) in sickle cell patients is

A

Streptococcus pneumoniae (encapsulated organism)

Also H. influenzae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Prophylaxis for asplenic patients (either from sickle cell or other causes) to not develop bacteremia

A

Penicillin and pneumococcal vaccination

vs. Streptococcus pneumoniae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Osteomyelitis in patients with sickle cell disease caused by:

A

Salmonella

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Voluminous, watery diarrhea that quickly leads to severe dehydration

A

Cholera (Vibrio cholerae) - rice water diarrhea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Patients with chronic liver disease are at increased risk of rapid onset sepsis and watery diarrhea by

A

Vibrio vulnificus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

Patients with cystic fibrosis are at increased risk for infection with

A

Pseudomonas aeruginosa (ox+, gram- rod) - pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

Ingestion of this particular drug makes patients more susceptible for infection with Vibrio cholerae

A

Ingestion of proton-pump inhibitors (PPI) = achlorydria = more risk for infection with V. cholerae.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Dysuria + mucoid urethral discharge + unprotected sexual intercourse

A

Neisseria gonorrhea (gonococcal urethritis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Gram negative diplococci with leukocytes that can be cultured on Thayer-Martin VCN

A

Neisseria gonorrhea (gonococcal urethritis)

82
Q

What type of medium is Thayer - Martin VCN for Neisseria gonorrhea?

A

Selective.

It has Vancomycin (vs g+), Colistin + TMP-SMX (vs g - other than N. gon) and Nystatin (vs fungi)

83
Q

Examples of differential media for organism analysis

A

MacConkey and Eosin Methylene Blue (show enteric organisms)

84
Q

Organisms that ferment lactose will appear _____ on MacConkey agar and ____ on EMB agar (Eosin Methylene Blue)

A

Pink on MacConkey

Black on EMB

85
Q

Examples of enrichment media

A

X and V factors for Haemophilus

Anaerobic for Clostridium

86
Q

Organism related to eating home-canned foods

A

Clostridium botulinum (toxin) - preformed neurotoxin

87
Q

Clinical manifestations of clostridium botulinum toxin

A

Both nicotinic (dysphagia, ptosis) and muscarinic (dry mouth)

88
Q

Botulims clinical manifestations

A

Dyplopia, dysphagia, dysphonia 3Ds.

Nausea, vomiting, abdominal pain

89
Q

Clostridium toxin causes disease by blocking Ach _________ into the neuromuscular synapse (picture)

A

release

90
Q

Is clostridium toxin heat-labile? (destroyed by heating)

A

Yes

91
Q

Virulence factor that forms part of outer peptidoglycan layer of S aureus

A

S aureus = Protein A

92
Q

Protein A binds to ___ portion of the ____ antibodies at the complement-binding site and prevents _________ activation.

A

S aureus protein A binds to Fc portion of IgG and prevents complement activation, opsonization and phagocytosis.

93
Q

Rapid onset muscle pain + fever + hemorrhagic bullae + tissue edema (crepitus) = Spontaneous gas gangrene + colonic malignancy

A

Clostridium septicum

94
Q

spore-forming, exotoxin-forming, gram positive forming bacterium in GI tract in humans

A

Clostridium septicum

95
Q

Which gas gangrene organism is associated with preceding trauma?

a) C perfingens
b) C septicum

A

C perfringens = preceding trauma

C septicum = NO preceding trauma but underlying colonic malignancy

96
Q

Gram neg bacterium that causes rapid-onset sepsis + bullous skin lesions in patients with HEMOCHROMATOSIS

A

Vibrio vulnificus

this organism is dependent on free iron for growth

97
Q

Most common pathogen causing cystitis and acute pyelonephritis

A

E. Coli

98
Q

Second most common cause of UTI in women after E.coli

A

Staphylococcus saprophyticus

99
Q

Aerobic, partially acid fast, Gram-positive rod that affects immunocompromised patients (Pneumonia + CNS involvement)

A

Nocardia

100
Q

Most common manifestation of Nocardia infection

A

Bronchopneumonia (can also lead to multiloculated brain abcesses and seizures)

101
Q

Microscopic difference between Nocardia and Actinomyces

A

Nocardia has mycolic acid (partially acid-fast) and Actinomyces doesn’t.

Nocardia presentation is similar to TB and Actinomyces causes cervicofacial infections (mandibular)

102
Q

Difference in growing pattern of Mycobacterium tuberculosis vs. Nocardia

A

M tuberculosis grows in long, serpentine cords (cord factor)
Nocardia grows in thin, branching filaments.

103
Q

If there’s a presentation of a TB like bronchopneumonia in immunocompromised host but ALSO signs or symptoms of brain abcess, you think about:

A

Nocardia.

104
Q

Fluid-filled cavity in liver + fevers + chills + RUQ abdominal pain in underdeveloped country

A

Liver abscess by Protozoa

Entamoeba histolytica

105
Q

Fluid-filled cavity in liver + fevers + chills + RUQ abdominal pain in developed countries

A

Liver abscess by Bacterial infection

106
Q

Causes of Hepatic abscess:

A
  • Staphylococcus aureus (via hematogenous seeding)
  • E.coli, Klebsiella, Enterococci (enteric bacteria)
  • Entamoeba histolytica (Protozoo)
107
Q

Most common cause of viral gastroenteritis in developed countries (outbreaks)

A

Norovirus

Vomiting + diarrhea, NO blood or mucus

108
Q

Norovirus is resistant to inactivation by _____ , ______ and ________ enzymes

A

acid, bile and pancreatic enzymes

109
Q

Gram-negative
Lactose-fermenting
Indole-positive
Rods

A 
Escherichia coli (E. coli) 
(Also Klebsiella, enterobacter, citrobacter and serratia)
110
Q

Oxidase-positive
Non-lactose fermenting
Gram-negative rod

A

Pseudomonas aeruginosa

111
Q

Distinguish between a UTI secondary to E. coli or Enterobacter cloacae (Both are lactose fermenting, gram negative rods)

A

E. coli is also indole positive

E. cloacae is not

112
Q

Most common cause of viral meningitis

A

Enteroviruses (coxsackie, echovirus, poliovirus)

113
Q

Most common microbe in bacterial meningitis in ADULTS

A
  1. Streptococcus pneumoniae

2. Neisseria meningitidis

114
Q

Most common microbe in bacterial meningitis in NEONATES

A
  1. Group B Streptococcus (B. Agalactiae)

2. Gram negative bacilli.

115
Q

CSF cell differential (WBC) between bacterial and viral meningitis

A

Viral: <500 cells (predominantly lymphocytic)
Bacterial: >1000 cells (predominantly neutrophilic)

116
Q

CSF glucose & protein count in BACTERIAL meningitis

A

Low glucose <45 (bacteria eat glucose)

Protein >250

117
Q

CSF glucose & protein count in VIRAL meningitis

A

Glucose normal or slightly reduced (40-70)

Protein <150

118
Q

Aseptic meningitis etiology is usually:

A

Viral

119
Q

If meningits was caused by Mumps virus (paperas, parotiditis) is accompanied of _________ in 50% of cases.

A

Parotitis (Unlikely in a fully-immunized child)

120
Q

H. influenzae type b is the most invasive strain of Haemophilus influenzae due to its _________ ________ capsule

A

Polyribosylribitol phosphate capsule (PRP)

121
Q

What is the function of the Polyribosylribitol capsule on H. influenzae type b?

A

Inhibits complement-mediated phagocytosis (allows it to survive in bloodstream)

122
Q

Most common cause of self-limited “travelers diarrhea”

A

ETEC = Enterotoxigenic Escherichia coli

123
Q

What does the LT (heat stable) ETEC enterotoxin resembles?

A

ETEC LT toxin resembles Cholera toxin

(LT increases IC cAMP in gut mucosal cells by activating Gs and adenylate cyclase - increased secretion of Na, H2O and electrolytes –> watery diarrhea)

124
Q

Enterotoxins formed by ETEC

A

LT - heat labile and

ST - heat stable

125
Q

IFN - gamma release assays (IGRAs) test for:

A

Latent tuberculosis infections (LTBI)

- measure cell - mediated immunity.

126
Q

Can skin tests or IGRAs diagnose active TB infection?

A

No.

127
Q

Impetigo is commonly caused by:

A
  1. Staphylococcus aureus

2. Group A-beta hemolytic Streptococcus (S pyogenes)

128
Q

Impetigo presentation

A

Blistering perioral eruption with a golden yellow crust.

Can cause PSGN 1 - 2 weeks after skin or pharyngeal infection

129
Q

Postestreptoccoccal glomerulonephritis presentation

A

Facial edema, dark colored urine, nephrITIC range proteinuria, urinary red blood cells cast

(After GAS Group A Streptococcus infection)

130
Q

Acute Rheumatic Fever (ARF) follows an untreated episode of:

A

GAS (Group A Streptococcus) pharyngitis.

NOT in GAS skin infection

131
Q

Triad of disseminated gonorrheal infection

A
  • Arthritis
  • Dermatitis
  • Tenosynovitis

In sexually active woman

132
Q

Certain bacteria (N gonorrhea, N meningitidis, Strep pneumoniae and H. influenzae) produce IgA proteases and this facilitates:

A

Bacterial adherence to mucosa

133
Q

Staphylococcal protein A binds to Fc portion of IgG preventing:

A

Complement fixation (impairment of complement-mediated cell lysis)

134
Q

Microorganism responsible for Supurative parotitis in adults:

A

Staph aureus

135
Q

Elevated serum amylase without pancreatitis in a patient post intubation or dehydrated:

A

Suppurative parotitis (Staph aureus)

136
Q

Primary amoebic encephalitis

A

Naegleria fowleri

137
Q

Exposure to Naegleria fowleri (primary amoebic encephalitis) occurs during:

A

Recreational water activities (warm water)

138
Q

Motile trophozoites on CSF wet mount

A

Naegleria fowleri

139
Q

Management of Naegleria fowleri

A

Amphotericin B (but all cases fatal)

140
Q

Site of primary infection Cryptococcus neoformans

A

Lungs

from soil with bird droppings. Primary asymptomatic lung infection

141
Q

(Picture) cryptococcus neoformans with ink stain
In a patient with HIV, slowly worsening headache, fever and confusion, this image demonstrates _________ _________ and it was obtained with _____ _____ method

A

Cryptococcus neoformans with India ink method

Round-oval yeast with a THICK polysaccharidae capsule

142
Q

If a patient undergoes polysaccharidae antigen testing using latex agglutination and the result is positive, we think of:

A

Cryptococcus neoformans

143
Q

Acute bacterial meningitis causing pathogens that colonize nasopharynx

A

Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenzae

144
Q

Staphylococcus epidermidis is a coagulase-negative component of normal skin flora that causes body infection with its ability to form:

A

Staph epidermidis = Biofilms

145
Q

Definitive treatment for infections caused by biofilm-producing organisms require

A

Removal of foreign body

146
Q

Biofilm-producing organisms:

- Prosthetic devices and intravenous catheters

A

Staphylococcus epidermidis

147
Q

Biofilm-producing organisms:

- Streptococcus mutans & streptococcus sanguinis

A

Dental plaques

148
Q

Biofilm-producing organisms:

- Cystic fibrosis pneumoniae, contact lenses

A

Pseudomonas aeruginosa

149
Q

Biofilm-producing organisms:

- Viridans group streptococci

A

Endocarditis

150
Q

Biofilm-producing organisms

- Nontypable haemophilus influenzae

A

Otitis media

151
Q

If you incubate an exudate specimen from a large yeast with a single bud from someone who went to the Great Lakes at 24ºC and a multicellular structure with branching, tubular cells grow, you think of:

A

Blastomyces dermatitidis

152
Q

Fungal species that display different morphologic characteristics in different environments (temperature) are called:

A

Dimorphic

153
Q

Dimorphic fungi form molds at _________ temperatures (__–___) and form ________ at body temperatures (37ºC)

A
  • Molds at ambient temperatures (25-30ºC)

- Yeasts (single cells) at body temperature (37ºC)

154
Q

Fungal species:

  • Associated with gardening, transmitted by thorn prick
  • Pustules, ulcers and nodules in lymphatics
  • Round or cigar-shaped budding yeasts is biopsy
A

Sporothrix schenckii

155
Q

Fungal species:
- Southwestern states (desert zones) mold in soil
- Pulmonary and disseminated form
(flu-like illness, cough, erythema nodosum // affects skin, bones and lungs)
- Biopsy: Thick walled spherules filled with endospores

A

Coccidioides immitis

They like thick cocc in the south with spherules filled with spermathoendospores

156
Q

Fungal species:
- Ohio and Mississippi River valleys
- Soil, bird and bat droppings (coops and caves)
- Similar to TB (lung granulomas with calcifications)
- Disseminated: lungs, spleen, liver
Biopsy: Oval yeast WITHIN macrophages

A

Histoplasma capsulatum

Capsulatum b/c macrophages look like their capsule when H. cap is inside them

157
Q

Fungal species:

  • Ohio and Mississippi River valleys + Great Lakes (found in soil)
  • Pulmonary pneumonia (disseminated form is common and severe)
  • Biopsy: large, round yeasts with doubly refractile wall and SINGLE broad-based bud.
A

Blastomyces dermatitidis

158
Q

Fungal species:

  • Central and South America
  • Mucocutaneous: ulcers that can progress to lymph nodes and lungs
  • Multiple blastoconidia
  • Biopsy: cells covered in budding blastoconidia
A

Paracoccidioides brasilensis

159
Q

Medically important dimorphic fungi include (5)

A
  • Sporothrix schenckii
  • Coccidioides immitis
  • Histoplasma capsulatum
  • Blastomyces dermatitidis
  • Paraccoccidioides brasilensis
160
Q

AB exotoxin that inhibits proteins synthesis by ADP ribosylation of EF-2 in an immigrant child with coalescing pseudomembrane pharyngeal exudates and inadequate vaccination

A

Diphteria toxin - Corynebacterium diphteriae

161
Q

On microscopic examination of a child with sore throar, fever, cervical adenopathy and pharyngeal exudates they find unencapsulated, gram+ rods in clumps that look like Chinese characters.
You can stain its metachromatic granules with aniline dyes like methylene blue

A

Aniline or methylene blue dies + chinese =

Corynebacterium diphteriae

162
Q

Diphteria toxin causes cell death by

A

Inhibiting cell protein synthesis

163
Q

Mycobacteria that appear as parallel chains (serpentine cords) under microscopy

A

Micobacterium tuberculosis

164
Q

Function of cord factor in mycobacterium tuberculosis

A

prevent macrophage-mediated destruction &

Drives the formation of caseating granulomas

165
Q

Virulence of M tuberculosis correlates with the formation of _______ __________ that inhibit phagolysosome acidification and leads to formation of caseating granulomas

A

Serpentine cords (cord factor)

166
Q

Which E.coli virulence factor prevents phagocytosis and complement-mediated lysis in neonatal meningitis?

A

KI capsular polysaccharide

167
Q

E. coli virulence factor that inactivates the 60s ribosomal component, halting protein synthesis and causing cell death in bloody Gastroenteritis

A

Verotoxin (shiga-like toxin)

168
Q

E. coli virulence factor specific to bacteremia and septic shock where macrophages activation causes widespread release of IL-1, IL-6 and TNF-alpha

A

LPS (Lipopolysaccharidae)

169
Q

In watery gastroenteritis, what is the mechanism of E. coli Heat Stable (ST) and Heat Labile (HL) enterotoxins?

A

Promote fluid & electrolyte secretion from intestinal epithelium

170
Q

Which virulence factor from E. coli allows adhesion to uroepithelium in UTI?

A

P. fimbriae

171
Q

Second most common cause of neonatal meningitis in the USA after group B streptococcus agalactiae?

A

E. coli

motile, gram - , facultative anaerobe, ferments lactose and glucose, MacConkey+ pink-red-appearance

172
Q

Patient with HIV + seizures and multiple ring-enchancing lesions with mass effect

A

Toxoplasma gondii

173
Q

Obligate intracellular protozoan whose host is a cat (feces-oocysts, undercooked meat- pseudocysts)

A

Toxoplasma gondii

174
Q

First line treatment for cerebral Toxoplasmosis

A

pyrimethamine & sulfadiazine

or pyrimethamine + clindamycin) + leucovorin (folinic acid

175
Q

Primary and secondary most common causes or ring-enhancing lesions with mass effect on the brain in HIV

A
  1. Toxoplasma gondii

2. Primary central nervous system lymphoma (PCNSL)

176
Q

Which virus is identified in almost all cases of Primary central nerous system lymphoma in patients with HIV (diffuse, large-cell, Non-Hodgkin cell lymphoma)

A

Epstein-Barr virus (B cells CD21)

177
Q

Most important host factor in preventing influenza infection in patients either vaccinated or past-infected with the virus

A

Humoral response with antibodies directed against HEMAGLUTTININ

(major adaptive immune mechanisms that prevent reinfection with the influenza virus include anti-hemagluttinin antibodies)

178
Q

(picture of clue cells) what other clinical findings can we find in this patient with clue cells and Bacterial Vaginosis?

A

Garnerella vaginalis (bacterial vaginosis)

  • Thin off-white discharge
  • fishy odor
  • NO inflammation
179
Q

Gardnerella vaginalis treatment

A

Metronidazole or clindamycin

180
Q

Thin, yellow-green malodorous, frothy discharge + vaginal inflammation

A

Trichomoniasis (Trichomonas vaginalis)

181
Q

Motile trichomonads on lab finding of vaginal discharge. Treatment?

A

Trichomoniasis tx = Metronidazole (+ treat sexual partner)

182
Q

Pseudohyphae and normal pH in vaginal discharge lab findings. Treatment

A

Fluconazole (it’s candida albicans)

183
Q

Anaerobic, gram negative rod that is best diagnosed with clue cells + Whiff test (KOH)

A

Bacterial vaginosis (gardnerella vaginalis)

184
Q

Cat-scratch disease (regional lymphadenopathy) in an AIDS patient can cause:

A

Cat-scratch = Bartonella henselae

Severe form = Bacillary angiomatosis

185
Q

Bacillary angiomatosis presentation

A

Violaceous, highly vascular cutaneous lesions.

186
Q

Ddx between Bacillary Angiomatosis (BA - Bartonella henselae) and Kaposi sarcoma is made with:

A

Test for Human-Herpesvirus 8

If positive = Kaposi sarcoma

187
Q

Ecthyma gangrenosum (EG) is strongly associated with infection by this microorganism

A

Pseudomonas aeruginosa

188
Q

Neutropenic patients who are hospitalized, have burns or have indwelling catheters have predisposition for:

A

Pseudomonas aeruginosa infection (and Ecthyma gangrenosum)

189
Q

Cephalosporin-resistant organisms

A
  • Listeria monocytogenes
  • MRSA
  • Enterococci
190
Q

Treatment of choice for Listeria

A

Ampicillin

191
Q

Hepatitis C virus presents multiple errors during replication because there is no proofreading of ___ to ____ exonuclease activity in its RNA polymerase

A

3’ to 5’

192
Q

Patient with new or worsening back pain, fever and recent endocarditis or bacteremia (especially S aureus) most likely have

A

Vertebral osteomyelitis

193
Q

Initial evaluation of vertebral osteomyelitis includes

A

Blood cultures and MRI of the spine.

194
Q

Facultative intracellular gram + bacillus that multiplies in refrigerated conditions.
Important cause of foodborne illness, outbreaks occur with contaminated food products (processed meat, soft cheeses, raw fruits - strawberry, and vegetables)

A

Listeria monocytogenes

195
Q

Pregnant women are at greater risk of Listeria monocytogenes infection in the _____ trimester and present with _____ _____ symptoms and ______ _____

A

Third
Flu-like symptoms
Preterm labor and neonatal sepsis (with generalized skin rash)

196
Q

Coinfection of a host cell by 2 viral strains, resulting in progeny virions that contain nucleocapsid proteins from one strain and the unchanged parental genome of the other strain

A

Phenotypic mixing (occurs with viral human and avian or swine influenza)

197
Q

Gram positive cocci in pairs, in a patient in a dormitory (Neisseria meningitidis) way of getting into the meninges

A

Pharynx —> Blood —> Choroid plexus —> meninges

198
Q

Septic abortion microbiologic causes

A
  • Gram negative bacilli

- Staphylococcus aureus

199
Q

Clinical presentation of septic abortion

A

Fever, chills, abdominal pain, bloody or purulent vaginal discharge.
Boggy and tender uterus with dilated cervix

200
Q

Findings in pelvic ultrasound in septic abortion

A

Retained products of conception
Increased vascularity
Echogenic material in the cavity
Thick endometrial stripe.

01. Step 1 mine (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions