Microbiology 1 Flashcards
1
Q
Two selective gene mutations responsible for Isoniazid resistance
A
- Decrease in bacterial EXPRESSION of catalase-peroxidase enzyme (required por ISZ activation)
- Modification of the protein target binding site for ISZ.
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)
3
Q
In which areas can Isoniazid reach therapeutic levels?
A
- Within macrophages
- Areas of caseous necrosis
- Cerebrospinal Fluid
4
Q
Erythema infectiosum (5th disease) is caused by
A
Parvovirus B19
single-stranded DNA virus
5
Q
The “slapped-cheek” rash develops in ____________ AFTER the symptoms have resolved
A
Parvovirus B19
6
Q
The lacy, reticular rash in Parvovirus B19 (erythema infectiosum) results from___________
A
Immune complex deposition
timing coincides with increasing IgM and IgG
7
Q
Parvovirus B19 (from Erythema infectiosum - 5th disease) replicates in ____________
A
Erythrocyte precursors in the bone marrow
8
Q
Cellular receptor for Parvovirus B19 in erythrocyte precursors
A
P antigen (globoside) - cellular receptor for Parvovirus B19
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)
10
Q
Nonspecific prodrome (malaise, fever, congestion) \+ Slapped-cheek \+ Lacy, reticular body rash
A
Erythema infectiosum (Parvovirus B19)
11
Q
Hepatitis E virus type
A
Hep E
- UnEnveloped
- Single-stranded RNA
- Spreads through fecal-oral route
12
Q
Most concerning feature of hepatitis E infection
A
High mortality rate in infected prEgnant women
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)
14
Q
Is Hep E associated with chronic liver disease or carried state?
A
NO. with neither
Hep E is self-limited.
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)
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
17
Q
Blastomyces dermatitidis is a:
A
dimorphic fungus
18
Q
Blastomyces dermatitidis causes infection in: _________ people
A
Immunocompetent people
19
Q
Endemic area of Blastomyces dermatitidis
A
Mississippi, Ohio
(found in mold, soil, dogs, horses) = farm!
20
Q
Transmission route of Blastomyces dermatitidis:
A
Respiratory —> lungs —-> Yeast (thermal dimorphism)
21
Q
Diseases that Blastomyces dermatitidis infection can mimic:
A
- Community-acquired pneumonia (resolves spontaneously)
- Chronic pneumonia (like TB, other fungi or cancer)
22
Q
Findings in pulmonary blastomycosis (Blastomyces dermatitidis)
A
- Granuloma
23
Q
When can we see EXTRAPULMONARY findings in patients with blastomycosis (Blastomyces dermatitidis)
A
Immunocompromised patients
24
Q
Round yeast with thick walls and broad-based budding
A
Blastomyces dermatitidis (she thick AF)
25
Preferred treatment for Blastomycosis (Blastomyces dermatitidis)
Itraconazole
26
Farmer from Mississippi or Ohio that resembles TB or pneumonia but who is immunocompetent (no HIV)
Blastomycosis (Blastomyces dermatitidis)
27
Hepatitis A is a ______ ________virus with an average incubation of ______ days
Hep A RNA picornavirus
| incubation 30 days.
28
Transmission of Hep A
Fecal-oral (overcrowding and poor sanitation - think shitty cafeterias)
29
Hep A outbreaks result from:
- Contaminated water or food
| - Shellfish (raw or steamed) !!!
30
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
Hep A infection
31
Aversion to smoking + malaise, fatigue, anorexia, nausea, vomiting, mild abdominal pain
Hep A infection
32
Is hepatomegaly seen in Hepatitis A?
Hell yeah
33
What spikes early in Hep A and what increases later?
a) serum AminoTransferases
b) Billirubin
c) Alkaline phosphatase
Hep A first spike:
1. AminoTransferases
2. Bilirrubin and Alkaline Phosphatase
34
Marker or active Hep A disease
Anti-HAV IgM
35
Does Hep A progress to chronic-hepatitis or cirrhosis or risk of hepatocellular carcinoma?
Nah bro.
| Hep A is self-limited and pretty chill
36
Light microscopy, budding yeasts with pseudohyphae
(picture) of light microscopy Candida fungi yeast (single cell) form
37
Test specific to distinguish Candida albicans from other candida species
Germ tube test
38
Inoculation of ________ _________ into serum at 37ºC for 3 hours leads to formation of hyphae from yeast. This test is called ______ _______ test
Candida albicans 37ºC for 3 hrs = germ tube test (diagnostic)
39
In immunocompromised patients, Candida can cause:
Disseminated disease that affects every organ system (preumonia, esophagitis, right-sided endocarditis, abcesses and candidemia sepsis)
40
Most common cause of opportunistic mycosis
Candida albicans
41
CSF findings:
- Pleocytosis (elevated leukocyte count) w/left shift
- Elevated protein
- Low-normal glucose
Bacterial meningitis
42
Facultative intracellular (grows in macrophages), gram positive rod with flagellar-based tumbling motility
Listeria monocytogenes
43
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.
Listeria monocytogenes
| Meningitis in immunocompromised adults, can also be delivered transplacentally
44
Antibiotic of choice for Listeria
Ampicillin
ListeriA
m
p
i
45
Q fever
Coxiella burnetti
46
Coxiella burnetti infection occurs by:
Inhalation of bacteria from air contaminated from animal waste (farms - waste from cattle and sheep)
47
Acute Q fever (Coxiella burnetti) presentation:
- Nonspecific febrile illness >10 days
- Fatigue, myalgias
- Severe debilitating headaches (retroorbital) + photophobia
- Pneumonia (lobar consolidation)
- Increased liver enzymes
- Thrombocytopenia
48
Chronic Q fever (Coxiella burnetti)
Fatal if untreated
| - infective endocarditis in patients with valve disease
49
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:
Enterotoxigenic Staph aureus.
50
Pathologic mechanism of foodbourne illness where the person ingests a preformed enterotoxin
Staph aureus
51
Pathologic mechanism of foodbourne illness where person has enterotoxin made in their intestine
- Clostridium perfringens
- ETE.C - STE.C
- Vibrio cholerae
(> 1 day onset / Watery-bloody diarrhea)
52
Clinical manifestations of ingestion of heat-stable enterotoxin (vomiting, nausea, abd cramping) occur with:
- Staph aureus (mayo, egg, chicken)
| - Bacillus cereus (rice - reheated)
53
Tzank smear (picture)
Multinucleated giant cells in HSV (Herpes Simplex Virus) infection
54
What is the difference in a Tzank smear between HSV (Herpes Simplex Virus) and Varicella-Zoster virus (VZV) infection?
There is no difference in their Tzank smears
55
Primary infection with HSV-1
Gingivostomatitis
| Painful vesicles that cover lips and gingiva, may appear in palate and oropharynx
56
Primary reason for hospitalization in primary infection with HSV-1
Dehydration (2ndary to pain in gingivostomatitis)
57
Difference between HSV-1 primary infection and reactivation of latent herpes infection clinical manifestations
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
58
Enveloped RNA virus that does NOT contain a replicase or RNA polymerase
Hep D virus
59
Hep D virus can only finish its replication cycle in the setting of coinfection with:
Hep B virus
| B+D Big Dick
60
Fulminant viral hepatitis can occur in these types of Hepatitis Viruses:
All of them A,B,C,D,E
61
Hepatocellular carcinoma is most commonly associated with Hep ____ infection
Hepatitis C or B = HeBatocellular Carcinoma
62
Autoclave machines work at a minimum of ____°C
134 °C
63
Lower temperatures in autoclave (less than 134 °C) can lead to _______-______ bacteria to develop.
Spore-forming bacteria (Bacillus and Clostridium) - only survive up to 120 °C
64
Common pathogenic spore-forming bacteria
Clostridium and Bacillus
| C. perfringens, C. botulinum, Bacillus anthracis
65
If a patient has:
Positive Anti-Hbs
Negative Anti-HBc IgG
What is the best diagnosis?
Has been vaccinated against Hep B virus
| presence of Anti-HBs but NOT Anti-HBc IgG
66
In contrast to the vaccine, which only includes HBsAg, infection with Hep B virus exposes patients to additional antigens, such as:
Hepatitis B core antigen (HBcAg) which is found in the virus but not in the vaccine.
67
Patient who had a Hep B infection but is now recovered will show signs of these two antigens on serum:
1. Anti-HBsAg
| 2. Anti-HBcAg (important in infected individuals!)
68
Bacterial meningitis in ADULTS in most commonly caused by:
1. Streptococcus pneumoniae
| 2. Neisseria meningitidis
69
Bacterial meningitis triad
- HIGH fever (more than 38°C)
- Stiff neck (pain)
- Altered level of consciousness
- Generalized headache
70
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
Lumbar puncture
| + blood culture, + empiric antibiotics + LP with CSF analysis for abx sensitivity
71
```
Streptococcus gallolyticus (S bovis) - nonenterococcal group D streptococci
mainly causes:
```
SBE - Subacute Bacterial Endocarditis
| similar to S viridans
72
Bacteremia or endocarditis caused by S gallolyticus is associated with this other disease:
Colonic cancer (25% cases)
73
Most common organism causing bacteremia (+sepsis) in sickle cell patients is
Streptococcus pneumoniae (encapsulated organism)
Also H. influenzae
74
Prophylaxis for asplenic patients (either from sickle cell or other causes) to not develop bacteremia
Penicillin and pneumococcal vaccination
| vs. Streptococcus pneumoniae
75
Osteomyelitis in patients with sickle cell disease caused by:
Salmonella
76
Voluminous, watery diarrhea that quickly leads to severe dehydration
Cholera (Vibrio cholerae) - rice water diarrhea
77
Patients with chronic liver disease are at increased risk of rapid onset sepsis and watery diarrhea by
Vibrio vulnificus
78
Patients with cystic fibrosis are at increased risk for infection with
Pseudomonas aeruginosa (ox+, gram- rod) - pneumonia
79
Ingestion of this particular drug makes patients more susceptible for infection with Vibrio cholerae
Ingestion of proton-pump inhibitors (PPI) = achlorydria = more risk for infection with V. cholerae.
80
Dysuria + mucoid urethral discharge + unprotected sexual intercourse
Neisseria gonorrhea (gonococcal urethritis)
81
Gram negative diplococci with leukocytes that can be cultured on Thayer-Martin VCN
Neisseria gonorrhea (gonococcal urethritis)
82
What type of medium is Thayer - Martin VCN for Neisseria gonorrhea?
Selective.
It has Vancomycin (vs g+), Colistin + TMP-SMX (vs g - other than N. gon) and Nystatin (vs fungi)
83
Examples of differential media for organism analysis
MacConkey and Eosin Methylene Blue (show enteric organisms)
84
Organisms that ferment lactose will appear _____ on MacConkey agar and ____ on EMB agar (Eosin Methylene Blue)
Pink on MacConkey
| Black on EMB
85
Examples of enrichment media
X and V factors for Haemophilus
Anaerobic for Clostridium
86
Organism related to eating home-canned foods
Clostridium botulinum (toxin) - preformed neurotoxin
87
Clinical manifestations of clostridium botulinum toxin
Both nicotinic (dysphagia, ptosis) and muscarinic (dry mouth)
88
Botulims clinical manifestations
Dyplopia, dysphagia, dysphonia 3Ds.
| Nausea, vomiting, abdominal pain
89
Clostridium toxin causes disease by blocking Ach _________ into the neuromuscular synapse (picture)
release
90
Is clostridium toxin heat-labile? (destroyed by heating)
Yes
91
Virulence factor that forms part of outer peptidoglycan layer of S aureus
S aureus = Protein A
92
Protein A binds to ___ portion of the ____ antibodies at the complement-binding site and prevents _________ activation.
S aureus protein A binds to Fc portion of IgG and prevents complement activation, opsonization and phagocytosis.
93
Rapid onset muscle pain + fever + hemorrhagic bullae + tissue edema (crepitus) = Spontaneous gas gangrene + colonic malignancy
Clostridium septicum
94
spore-forming, exotoxin-forming, gram positive forming bacterium in GI tract in humans
Clostridium septicum
95
Which gas gangrene organism is associated with preceding trauma?
a) C perfingens
b) C septicum
C perfringens = preceding trauma
C septicum = NO preceding trauma but underlying colonic malignancy
96
Gram neg bacterium that causes rapid-onset sepsis + bullous skin lesions in patients with HEMOCHROMATOSIS
Vibrio vulnificus
| this organism is dependent on free iron for growth
97
Most common pathogen causing cystitis and acute pyelonephritis
E. Coli
98
Second most common cause of UTI in women after E.coli
Staphylococcus saprophyticus
99
Aerobic, partially acid fast, Gram-positive rod that affects immunocompromised patients (Pneumonia + CNS involvement)
Nocardia
100
Most common manifestation of Nocardia infection
Bronchopneumonia (can also lead to multiloculated brain abcesses and seizures)
101
Microscopic difference between Nocardia and Actinomyces
Nocardia has mycolic acid (partially acid-fast) and Actinomyces doesn't.
Nocardia presentation is similar to TB and Actinomyces causes cervicofacial infections (mandibular)
102
Difference in growing pattern of Mycobacterium tuberculosis vs. Nocardia
M tuberculosis grows in long, serpentine cords (cord factor)
Nocardia grows in thin, branching filaments.
103
If there's a presentation of a TB like bronchopneumonia in immunocompromised host but ALSO signs or symptoms of brain abcess, you think about:
Nocardia.
104
Fluid-filled cavity in liver + fevers + chills + RUQ abdominal pain in underdeveloped country
Liver abscess by Protozoa
| Entamoeba histolytica
105
Fluid-filled cavity in liver + fevers + chills + RUQ abdominal pain in developed countries
Liver abscess by Bacterial infection
106
Causes of Hepatic abscess:
- Staphylococcus aureus (via hematogenous seeding)
- E.coli, Klebsiella, Enterococci (enteric bacteria)
- Entamoeba histolytica (Protozoo)
107
Most common cause of viral gastroenteritis in developed countries (outbreaks)
Norovirus
| Vomiting + diarrhea, NO blood or mucus
108
Norovirus is resistant to inactivation by _____ , ______ and ________ enzymes
acid, bile and pancreatic enzymes
109
Gram-negative
Lactose-fermenting
Indole-positive
Rods
```
Escherichia coli (E. coli)
(Also Klebsiella, enterobacter, citrobacter and serratia)
```
110
Oxidase-positive
Non-lactose fermenting
Gram-negative rod
Pseudomonas aeruginosa
111
Distinguish between a UTI secondary to E. coli or Enterobacter cloacae (Both are lactose fermenting, gram negative rods)
E. coli is also indole positive
| E. cloacae is not
112
Most common cause of viral meningitis
Enteroviruses (coxsackie, echovirus, poliovirus)
113
Most common microbe in bacterial meningitis in ADULTS
1. Streptococcus pneumoniae
| 2. Neisseria meningitidis
114
Most common microbe in bacterial meningitis in NEONATES
1. Group B Streptococcus (B. Agalactiae)
| 2. Gram negative bacilli.
115
CSF cell differential (WBC) between bacterial and viral meningitis
Viral: <500 cells (predominantly lymphocytic)
Bacterial: >1000 cells (predominantly neutrophilic)
116
CSF glucose & protein count in BACTERIAL meningitis
Low glucose <45 (bacteria eat glucose)
| Protein >250
117
CSF glucose & protein count in VIRAL meningitis
Glucose normal or slightly reduced (40-70)
| Protein <150
118
Aseptic meningitis etiology is usually:
Viral
119
If meningits was caused by Mumps virus (paperas, parotiditis) is accompanied of _________ in 50% of cases.
Parotitis (Unlikely in a fully-immunized child)
120
H. influenzae type b is the most invasive strain of Haemophilus influenzae due to its _________ ________ capsule
Polyribosylribitol phosphate capsule (PRP)
121
What is the function of the Polyribosylribitol capsule on H. influenzae type b?
Inhibits complement-mediated phagocytosis (allows it to survive in bloodstream)
122
Most common cause of self-limited "travelers diarrhea"
ETEC = Enterotoxigenic Escherichia coli
123
What does the LT (heat stable) ETEC enterotoxin resembles?
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
Enterotoxins formed by ETEC
LT - heat labile and
| ST - heat stable
125
IFN - gamma release assays (IGRAs) test for:
Latent tuberculosis infections (LTBI)
| - measure cell - mediated immunity.
126
Can skin tests or IGRAs diagnose active TB infection?
No.
127
Impetigo is commonly caused by:
1. Staphylococcus aureus
| 2. Group A-beta hemolytic Streptococcus (S pyogenes)
128
Impetigo presentation
Blistering perioral eruption with a golden yellow crust.
Can cause PSGN 1 - 2 weeks after skin or pharyngeal infection
129
Postestreptoccoccal glomerulonephritis presentation
Facial edema, dark colored urine, nephrITIC range proteinuria, urinary red blood cells cast
(After GAS Group A Streptococcus infection)
130
Acute Rheumatic Fever (ARF) follows an untreated episode of:
GAS (Group A Streptococcus) pharyngitis.
NOT in GAS skin infection
131
Triad of disseminated gonorrheal infection
- Arthritis
- Dermatitis
- Tenosynovitis
In sexually active woman
132
Certain bacteria (N gonorrhea, N meningitidis, Strep pneumoniae and H. influenzae) produce IgA proteases and this facilitates:
Bacterial adherence to mucosa
133
Staphylococcal protein A binds to Fc portion of IgG preventing:
Complement fixation (impairment of complement-mediated cell lysis)
134
Microorganism responsible for Supurative parotitis in adults:
Staph aureus
135
Elevated serum amylase without pancreatitis in a patient post intubation or dehydrated:
Suppurative parotitis (Staph aureus)
136
Primary amoebic encephalitis
Naegleria fowleri
137
Exposure to Naegleria fowleri (primary amoebic encephalitis) occurs during:
Recreational water activities (warm water)
138
Motile trophozoites on CSF wet mount
Naegleria fowleri
139
Management of Naegleria fowleri
Amphotericin B (but all cases fatal)
140
Site of primary infection Cryptococcus neoformans
Lungs
| from soil with bird droppings. Primary asymptomatic lung infection
141
(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
Cryptococcus neoformans with India ink method
| Round-oval yeast with a THICK polysaccharidae capsule
142
If a patient undergoes polysaccharidae antigen testing using latex agglutination and the result is positive, we think of:
Cryptococcus neoformans
143
Acute bacterial meningitis causing pathogens that colonize nasopharynx
Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenzae
144
Staphylococcus epidermidis is a coagulase-negative component of normal skin flora that causes body infection with its ability to form:
Staph epidermidis = Biofilms
145
Definitive treatment for infections caused by biofilm-producing organisms require
Removal of foreign body
146
Biofilm-producing organisms:
| - Prosthetic devices and intravenous catheters
Staphylococcus epidermidis
147
Biofilm-producing organisms:
| - Streptococcus mutans & streptococcus sanguinis
Dental plaques
148
Biofilm-producing organisms:
| - Cystic fibrosis pneumoniae, contact lenses
Pseudomonas aeruginosa
149
Biofilm-producing organisms:
| - Viridans group streptococci
Endocarditis
150
Biofilm-producing organisms
| - Nontypable haemophilus influenzae
Otitis media
151
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:
Blastomyces dermatitidis
152
Fungal species that display different morphologic characteristics in different environments (temperature) are called:
Dimorphic
153
Dimorphic fungi form molds at _________ temperatures (__--___) and form ________ at body temperatures (37ºC)
- Molds at ambient temperatures (25-30ºC)
| - Yeasts (single cells) at body temperature (37ºC)
154
Fungal species:
- Associated with gardening, transmitted by thorn prick
- Pustules, ulcers and nodules in lymphatics
- Round or cigar-shaped budding yeasts is biopsy
Sporothrix schenckii
155
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
Coccidioides immitis
| They like thick cocc in the south with spherules filled with spermathoendospores
156
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
Histoplasma capsulatum
| Capsulatum b/c macrophages look like their capsule when H. cap is inside them
157
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.
Blastomyces dermatitidis
158
Fungal species:
- Central and South America
- Mucocutaneous: ulcers that can progress to lymph nodes and lungs
- Multiple blastoconidia
- Biopsy: cells covered in budding blastoconidia
Paracoccidioides brasilensis
159
Medically important dimorphic fungi include (5)
- Sporothrix schenckii
- Coccidioides immitis
- Histoplasma capsulatum
- Blastomyces dermatitidis
- Paraccoccidioides brasilensis
160
AB exotoxin that inhibits proteins synthesis by ADP ribosylation of EF-2 in an immigrant child with coalescing pseudomembrane pharyngeal exudates and inadequate vaccination
Diphteria toxin - Corynebacterium diphteriae
161
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
Aniline or methylene blue dies + chinese =
| Corynebacterium diphteriae
162
Diphteria toxin causes cell death by
Inhibiting cell protein synthesis
163
Mycobacteria that appear as parallel chains (serpentine cords) under microscopy
Micobacterium tuberculosis
164
Function of cord factor in mycobacterium tuberculosis
prevent macrophage-mediated destruction &
| Drives the formation of caseating granulomas
165
Virulence of M tuberculosis correlates with the formation of _______ __________ that inhibit phagolysosome acidification and leads to formation of caseating granulomas
Serpentine cords (cord factor)
166
Which E.coli virulence factor prevents phagocytosis and complement-mediated lysis in neonatal meningitis?
KI capsular polysaccharide
167
E. coli virulence factor that inactivates the 60s ribosomal component, halting protein synthesis and causing cell death in bloody Gastroenteritis
Verotoxin (shiga-like toxin)
168
E. coli virulence factor specific to bacteremia and septic shock where macrophages activation causes widespread release of IL-1, IL-6 and TNF-alpha
LPS (Lipopolysaccharidae)
169
In watery gastroenteritis, what is the mechanism of E. coli Heat Stable (ST) and Heat Labile (HL) enterotoxins?
Promote fluid & electrolyte secretion from intestinal epithelium
170
Which virulence factor from E. coli allows adhesion to uroepithelium in UTI?
P. fimbriae
171
Second most common cause of neonatal meningitis in the USA after group B streptococcus agalactiae?
E. coli
| motile, gram - , facultative anaerobe, ferments lactose and glucose, MacConkey+ pink-red-appearance
172
Patient with HIV + seizures and multiple ring-enchancing lesions with mass effect
Toxoplasma gondii
173
Obligate intracellular protozoan whose host is a cat (feces-oocysts, undercooked meat- pseudocysts)
Toxoplasma gondii
174
First line treatment for cerebral Toxoplasmosis
pyrimethamine & sulfadiazine
| or pyrimethamine + clindamycin) + leucovorin (folinic acid
175
Primary and secondary most common causes or ring-enhancing lesions with mass effect on the brain in HIV
1. Toxoplasma gondii
| 2. Primary central nervous system lymphoma (PCNSL)
176
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)
Epstein-Barr virus (B cells CD21)
177
Most important host factor in preventing influenza infection in patients either vaccinated or past-infected with the virus
Humoral response with antibodies directed against HEMAGLUTTININ
(major adaptive immune mechanisms that prevent reinfection with the influenza virus include anti-hemagluttinin antibodies)
178
(picture of clue cells) what other clinical findings can we find in this patient with clue cells and Bacterial Vaginosis?
Garnerella vaginalis (bacterial vaginosis)
- Thin off-white discharge
- fishy odor
- NO inflammation
179
Gardnerella vaginalis treatment
Metronidazole or clindamycin
180
Thin, yellow-green malodorous, frothy discharge + vaginal inflammation
Trichomoniasis (Trichomonas vaginalis)
181
Motile trichomonads on lab finding of vaginal discharge. Treatment?
Trichomoniasis tx = Metronidazole (+ treat sexual partner)
182
Pseudohyphae and normal pH in vaginal discharge lab findings. Treatment
Fluconazole (it's candida albicans)
183
Anaerobic, gram negative rod that is best diagnosed with clue cells + Whiff test (KOH)
Bacterial vaginosis (gardnerella vaginalis)
184
Cat-scratch disease (regional lymphadenopathy) in an AIDS patient can cause:
Cat-scratch = Bartonella henselae
| Severe form = Bacillary angiomatosis
185
Bacillary angiomatosis presentation
Violaceous, highly vascular cutaneous lesions.
186
Ddx between Bacillary Angiomatosis (BA - Bartonella henselae) and Kaposi sarcoma is made with:
Test for Human-Herpesvirus 8
| If positive = Kaposi sarcoma
187
Ecthyma gangrenosum (EG) is strongly associated with infection by this microorganism
Pseudomonas aeruginosa
188
Neutropenic patients who are hospitalized, have burns or have indwelling catheters have predisposition for:
Pseudomonas aeruginosa infection (and Ecthyma gangrenosum)
189
Cephalosporin-resistant organisms
- Listeria monocytogenes
- MRSA
- Enterococci
190
Treatment of choice for Listeria
Ampicillin
191
Hepatitis C virus presents multiple errors during replication because there is no proofreading of ___ to ____ exonuclease activity in its RNA polymerase
3' to 5'
192
Patient with new or worsening back pain, fever and recent endocarditis or bacteremia (especially S aureus) most likely have
Vertebral osteomyelitis
193
Initial evaluation of vertebral osteomyelitis includes
Blood cultures and MRI of the spine.
194
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)
Listeria monocytogenes
195
Pregnant women are at greater risk of Listeria monocytogenes infection in the _____ trimester and present with _____ _____ symptoms and ______ _____
Third
Flu-like symptoms
Preterm labor and neonatal sepsis (with generalized skin rash)
196
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
Phenotypic mixing (occurs with viral human and avian or swine influenza)
197
Gram positive cocci in pairs, in a patient in a dormitory (Neisseria meningitidis) way of getting into the meninges
Pharynx ---> Blood ---> Choroid plexus ---> meninges
198
Septic abortion microbiologic causes
- Gram negative bacilli
| - Staphylococcus aureus
199
Clinical presentation of septic abortion
Fever, chills, abdominal pain, bloody or purulent vaginal discharge.
Boggy and tender uterus with dilated cervix
200
Findings in pelvic ultrasound in septic abortion
Retained products of conception
Increased vascularity
Echogenic material in the cavity
Thick endometrial stripe.
