Bacteriology Flashcards
1
Q
INFECTIVE ENDOCARDITIS:
IV drug user
A
Staphylococcus aureus
2
Q
INFECTIVE ENDOCARDITIS:
Prostethic valve
A
Staphylococcus epidermidis
3
Q
INFECTIVE ENDOCARDITIS:
S/p GU or GI surgery
A
Enterococcus faecalis
4
Q
INFECTIVE ENDOCARDITIS:
GI malignancy
A
Streptococcus bovis
5
Q
INFECTIVE ENDOCARDITIS:
Dental procedures
A
Streptococcus viridans
6
Q
Difference of TEN and Scalded Skin Syndrome
A
TEN: dermo-epidermal junction separation
SSS: epidermal separation at stratum granulosum
7
Q
How to distinguish Strep TSS from Staph TSS
A
Strep TSS: With pyogenic focus/inflammation and (+) blood CS
Staph: TSS: Without pyogenic focus/inflammation and (-) CS
8
Q
Causes of necrotizing pneumonia
A
K VAPS
Klebsiella (Friedlanders PNM)
Viral PNM
Aspergillus
Pseudomonas (Fleur De Lis)
Staphylococcus aureus
9
Q
Virulence factor of S. Aureus that prevents complement activation
A
Protein A (helps bacteria bind to Fc region of IgG and prevent phagocytosis)
10
Q
Virulence factor of S. Aureus that build an insoluble fibrin capsule
A
Coagulase
11
Q
Virulence factor of S. Aureus that causes leukocyte destruction and tissue necrosis
A
Panton-Valentine-Leukocidin
12
Q
Virulence factor of S. Aureus that detoxifies H2O2
A
Catalase
13
Q
Virulence factor of S. Aureus that inactivates Penicillin derivatives
A
Penicillinase
14
Q
S. Aureus spreading factor
A
Hyaluronidase (Dural Reynal factor)
15
Q
Gold color of S. Aureus is due to?
A
Staphyloxantin
16
Q
Hemolysis: Green or brown color surrounding colony
A
Partial/alpha hemolysis
17
Q
Hemolysis: Clear or colorless
A
Complete Hemolysis
18
Q
Toxins of S. aureus
A
Exfoliatin A and B - Scalded Skin Syndrome
Toxic Shock Syndrome toxin (TSST-1) - TSS
Enterotoxin - food poisoning
Alpha toxin - hemolysis and necrosis of skin
19
Q
Gene in MRSA responsible for resistance against methicillin
A
mecA gene - encodes
PBP2a
20
Q
How long is treatment for infective endocarditis done
A
4-6 weeks to 8 weeks
21
Q
Gastroenteritis in S. Aureus
Onset:
Food implicated:
A
Acute onset (4hrs) - due to preformed enterotoxin
Usually creamy food (potato or tuna made with mayonnaise, lasagna, fruit salad etc.)
22
Q
S. aureus osteomyelitis usual site
A
Children - long bones
Adult - vertebral
23
Q
Most affected valve in IV drug users
A
Tricuspid valve
24
Q
Hemolysis of the staphs
A
S. aureus: Beta hemolysis - yellow/golden colonies
S. Saprophyticus: nonhemolytic, whitish colonies
S. Epidermidis: nonhemolytic, whitish colonies
25
Unlike E. coli, S. saprophyticus is __________
Nitrite negative
26
Most common cause of prosthetic valve (usually mitral) endocarditis. Affects artificial materials by creating biofilm
Stapylococcus epidermidis
27
Honeymoon cystitis (24 hrs after sex)
2nd most commin cause of UTI in sexually active women
Staphylococcus saprophyticus
28
Organism with a positive PYR test
Streptococcus pyogenes (with formation of red compound)
29
Virulence enzymes of S. Pyogenes
Hyaluronidase - spreading factor
Streptokinase (fibrinolysin) - activates plasminogen
DNase (Streptodornase) - degrades DNA in exudates or necrotic tissue
C5a peptidase- inactivates complement C5A
30
Etiologic agent of Scarlet fever
Streptococcus pyogenes (Erythrogenic toxin)
31
Toxin of Streptococcus pneumoniae that causes AB formation; highly antigenic. Used to determine antecedent streptococcus infection
Streptolysin O (Oxygen labile)
32
Aside from S. Aureus, a milder TSS can be seen in ___________, due to the toxin ____________
Streptococcus pyogenes; Pyrogenic exotoxin A
33
Streptococcus protease that rapidly destroys tissue
Exotoxin B
34
Major virulence factor of GAS that inhibits activation of complement and protects organism from phagocytosis
M protein
35
Elevated titers of this AB suggests ANTECEDENT PHARYNGITIS
Anti-Streptolysin O
36
Elevated titers of this AB suggests ANTECEDENT SKIN INFECTION
Anti-DNAse B
37
This AB decreases efficiency of streptokinase in managing MI
Antistreptokinase
38
Brodie’s abscess
Staphylococcus aureus
39
Toxic Shock Syndrome
Staphylococcus aureus
40
Bullous impetigo
Staphylococcus aureus
41
Hidradenitis suppurativa and mastitis
Staphylococcus aureus
42
Erysipelas vs. Cellulitis
and caused by:
Erysipelas: superficial infection extending to dermal lymphatics
Cellulitis: deeper infection involving subcutaneous/dermal tissues
Streptococcus pyogenes facilitated by hyaluronidase
43
Necrotizing fascitiis
Streptococcus pyogenes (Exotoxin B)
44
A necrotizing fasciitis involving male genital area and perineum, often causes by mixed organisms but can be caused by GABHS. Also associated with DM taking SGLT-2
Fournier’s gangrene
45
Most common bacterial cause of sore throat
Streptococcus pyogenes
46
Peritonsillar and retropharyngeal (Quincy) abscess
Streptococcus pyogenes pharyngitis
47
Test to determine susceptibility to Scarlet Fever
Dick test
48
Scarlet fever and TSS is caused by _____________ infection. The toxin involved in scarlet fever is _____________ while the toxin involved in TSS is ____________
Streptococcus pyogenes; erythrogenic toxin; pyrogenic exotoxin A
49
Antecedent infections associated with ARF and Glomerulonephritis
ARF: post-pharyngitis ONLY
Glomerulonephritis: post-impetigo and post-pharyngitis
50
Characteristic of polyarthritis in ARF
Migratory, dramatic response to salicylates (aspirin)
51
ARF pathophysio
Cross reaction of ab to M proteins and antigens of joint, heart, and brain tissue
52
ARF is a Type ___________ hypersensitivity reaction
Type II, Cell-mediated
53
Sequela of ARF in heart (anong tawag sa body na yun)
Aschoff bodies; Anitschkow cells
54
Bacteria that Hydrolyzes hippurate and is with CAMP test positive
Streptococcus agalactiae;
(+) CAMP test - Arrowhead shaped zone of hemolysis perpendicular to S. aureus streak
55
A cause of UTI in pregnant women
Streptococcus agalactiae
56
Most commin cause of neonatal meningitis
Streptococcus agalactiae
*intrapartum fever (T>38)
*PROM (>18h)
*vaginal colonization
*complement def
* endometritis
57
When to screen for GBS colonization and how to administer prophylaxis in pregnant women
35-37 weeks AOG
Chemoprophylaxis with IV Penicillin or Ampicillin 4 hours before delivery
58
Libman Sacks Endocarditis/Marantic Endocarditis/Nonbacterial thrombotic endocarditis (Sterile vegetations)
S. Bovis
59
Encapsulated Bacteria
Some Strange Killer Bacteria Have Pretty Biolent Yet Nice Capsules
Streptococcus pneumoniae
Salmonella typhi
Klebsiella pneumoniae
Bacillus anthracis
Haemophilus influenzae
Pseudomonas
B Group Streptococci
Yersinia pestis
Neisseria Meningitidis
Cryptococcus neoformans
60
Lancet shape streptococcus
Streptococcus pneumoniae
61
Streptococcus pneumoniae has a positive _____________ reaction
Quellung
62
Streptococcus pneumoniae retards phagocytosis through
Capsule
63
S. Pneumoniae uses this for colonizatinon
IgA protease
64
Most common cause of CAP
Streptococcus pneumoniae
*blood tinged, pink, or rusty sputum
65
Strep pneumoniae can also cause
Otitis media
Sinusitis
Meningitis
66
Dental caries
S. Mutans
67
Subacute bacterial endocarditis (most common cause of native valve endocarditis)
S. sanguis
68
Brain abscess in Viridans Streptococcus
S. Intermedius
69
Medusa head morphology
Bacillus anthracis
70
The antiphagocytic capsule of Bacillus Anthracis is composed of
Poly-D-glutamate
71
Virulence factors of b. Anthracis
Lethal factor - inhibits signal transduction in cell division
Edema factor - calmodulin dependent adenylate cyclase
Protective antigen - allows entry of other 2
72
Woolsorters disease
Hemorrhagic mediastinitis
Inhalational anthrax
73
CXR finding of patient with inhalational anthrax
Mediastinal widening
74
Bacillus cereus diarrheal form is caused by its ______________ (______-like enterotoxin)
Bacillus cereus emetic form is caused by its ______________ (______-like enterotoxin)
Heat-labile toxin
(Cholera-like)
Heat-stable toxin (Staphylococcal-like)
75
Apart from food poisoning, what another condition could be caused by B. cereus?
Ophthalmitis - complete loss of light perception after 48 hrs of injury
76
Autonomic dysfunction may occur in Tetanus because
Loss of inhibition of preganglionic sympathetic neurons in lateral gray matter of spinal cord —> sympathetic hyperactivity —> inc circulating catecholamines
77
Preferred treatment for Tetanus
Metronidazole 400 mg rectally or 500 mg IV every 6 hours for 7 days
78
Transmitted via improperly preserved food (canned goods, alkaline vegetables, smoked fish, honey)
Clostridium botulinum
79
Flaccid paralysis of C. Botulinum has a ______________ pattern
Descending pattern
80
Triad of botulism
1. Symmetric descending flaccid paralysis (prominent bulbar involvement)
2. Absence of fever
3. Intact cognition
*Has anticholinergic effect: dry mouth, constipation, abdominal pain
81
Nonmotile but with rapidly spreading growth on culture media (stormy fermentation of milk); double hemolysis on blood agar
Clostridium perfringens
82
Major virulence factor of C. perfringens
Alpha toxin, lethicinase
83
Gas gangrene
Pain, edema, cellulitis with crepitation
Clostridium perfringens
84
Exotoxin in stool detected by cytopathic effect on cultured cells or ELISA
Clostridium difficile
85
Antibiotics that suppress normal flora and promote C. Difficile overgrowth
*Clindamycin
*2nd and 3rd Gen cephalosphorin
*Ampicillin
86
Pseudomembranous colitis
Clostridium difficule
*Exotoxin A (Enterotoxin)
*Exotoxin B (Cytotoxin)
Pseudomembranes: Yellow-white plaques on colonic mucosa
87
C. Difficile can precipitate flare up of this GI condition
Ulcerative colitis
*Toxic megacolon is a possible complication
88
How to differentiate C diff from UC
Chronic ang UC
89
DOC for C. Difficile
ORAL metronidazole or VANCOMYCIN
Oral vancomycin has poor intestinal absorption thus it would coat the lesions
90
Clostridial cause of nontraumatic myonecrosis in immunocompromised patients
Clostridium septicum
91
Clostridial cause of TSS in septic abortion
Clostridium sordellii
92
93
Antibiotic associated diarrhea
Clostridium difficile
94
Distinct horse barn odor on CCFA agar
Clostridium difficile
95
Chinese characters
Corynebacterium diphtheriae
96
Reddish metachromatic (Babes-Ernst/Volutin) granules are seen in
Corynebacterium diphtheriae
97
A test that detects toxigenicity of Corynebacterium diphtheriae
Modified Elek test
98
DOC for Corynebacterium diphtheriae
Erythromycin
99
Exotoxin of C. Diphtheriae
*Inhibits protein synthesis by adding ADP-ribose to elongation factor 2
*Subunit A - ADP ribosylating activity
*Subunit B - binds toxin to cell surface
*encoded by B-prophage
100
Thick gray pseudomembranes over tonsils and throat
C. Diphtheriae
101
Complications of C. Diphtheriae infections
Airway obstruction
Myocarditis - AV conduction block, dysrhythmia
Neural involvement - peripheral nerve palsies, GBS, palatal paralysis, neuropathies, cranial nerve and muscle paralysis
102
Test to determine susceptibility to infection by C. Diphtheriae
Shick test
103
Tumbling motility
Listeria monocytogenes
104
Cold enhancement: paradoxical growth in cold temperature
Listeria monocytogenes
105
Transmission is usually through consumption of unpasteurized milk products and food products that ate frequently refrigerated
Listeria monocytogenes
106
Listeria monocytogenes pathogenic factors:
Interacts with E-cadherin on surface of cells
Internalin
107
Listeria monocytogenes pathogenic factors:
Escape from phagosome
Listeriolysin
108
Listeria monocytogenes pathogenic factors:
Propels the bacteria through the membrane of one human cell and into another
Actin rockets (actin polymers)
109
Early onset neonatal listeriosis
Granulomatosis infantiseptica
Transplacental
Late miscarriage or birth complicated by sepsis, multiorgan abscesses, disseminated granulomas
110
Late onset neonatal listeriosis
Transmitted during childbirth
Meningitis or meningoencephalitis
111
Causative agents of Neonatal meningitis
SLE
Streptococcus agalactiae - most common
Listeria monocytogenes
Escherichia coli
112
Local trauma (broken jaw or dental extraction)
Actinomyces israelli
113
Hard, nontender swelling with sinus tracts draining sulfur granules
Actinomyces israelli
114
PID in those with IUDs
Actinomyces israelli
115
Lumpy jaw
Actinomyces israelli
116
Anaerobic culture - characteristic molar tooth colonies
Actinomyces israelli
117
Aerobic filamentous gram positive rods with aerial hyphae
Nocardia asteroides
118
Weakly acid fast - Fite faraco stain
Nocardia asteroides
119
Pulmonary infection that Mimics TB with negative PPD (immunocompromised)
Nocardia asteroides
120
DOC for Nocardia and Actinomyces
Sulfonamides for Nocardia (TMP-SMX); Penicillin for Actinomyces
121
Orange colonies
Nocardia asteroides
122
Cutaneous infection after trauma that spreads to CNS as brain abscesses (immunocompetent)
Nocardia asteroides
123
Waterhouse Friderichsen Syndrome
Neisseria Meningitides
*High fever
*Shock
*DIC
*widespread purpura
*Thrombocytopenia
*Adrenal insufficiency
124
Vaccines of Neisseria meningitides have the following serotypes
A, C, Y, W
125
Bacteria with IgA proteases
Neisseria meningitides
Neisseria gonorrhea
Haemophilus influenzae
Streptococcus pneumoniae
126
Beta-prophage encoded toxins
Shiga-like toxin (EHEC)
Botulinum toxin
Cholera toxin
Diphtheria toxin
Erythrogenic toxin (S. pyogenes)
127
Modified Thayer Martin antibiotics
Vancomycin - Gram (+)
Colistin/Trimetroprim/Polymixin - Gram (-) except Neisseria spp
Nystatin - fungi
128
Toxicity of gonococcal infections is related to this factor
Lipoolygosaccharide (LOS)
129
Expression of opaque colonies
Neisseria gonorrhea (Opa)
130
Antigenic variation in N. Gonorrhea
Pili
131
Ophthalmia neonatorum
Neisseria gonorrhea
132
Most common cause of urethritis
Neisseria gonorrhea
133
Most common cause of PID
Neisseria gonorrhea
134
Fitz-Hugh Curtis Syndrome
Neisseria gonorrhea
135
Septic arthritis in sexually active adults
Neisseria gonorrhea
136
Gold standard for diagnosis of gonorrheal infections
NAAT
*Male - (+) microscopic from urethral specimen, no need for further tests
*Female - (+) microscopic endocervix specimen, proceed to NAAT or culture
For reevaluation - Culture
137
DOC for gonorrhea
Ceftriaxone + Doxycycline (Frequent co-infection with Chlamydia trachomatis)
138
Gram positive cocci in clusters,
catalase positive, coagulase
positive
Staphylococcus aureus
139
Most common infection in open
fractures?
Staphylococcus aureus
140
Gram positive cocci in clusters,
catalase positive, coagulase
negative, Novobiocin resistant
Staphylococcus
saprophyticus
141
Gram positive cocci in clusters,
catalase positive, coagulase
negative, Novobiocin sensitive
Staphylococcus epidermidis
142
An IV drug user who develops
endocarditis. What is the
causative agent
Staphylococcus aureus
(Affects the tricuspid valve)
143
A patient with a prosthetic
heart valve develops
endocarditis. What is the
causative agent?
Staphylococcus epidermidis
144
A patient who underwent
dental surgery develops
endocarditis. What is the
causative agent?
Viridans Streptococci
145
A patient with marantic
endocarditis. Culture done
showing growth of S. bovis.
What is the next best step?
Colonoscopy to determine
presence of Colon cancer
146
A patient who underwent
GI/GU surgery who develops
endocarditis. What is the
causative agent?
Enterococcus faecalis
147
Gram positive cocci in chains,
catalase negative, beta hemolytic,
bacitracin resistant, CAMP positive
Streptococcus agalactiae
148
Gram positive cocci in chains,
catalase negative, beta hemolytic,
bacitracin sensitive, PYR test
positive
Streptococcus pyogenes
149
Jones criteria for acute
rheumatic fever includes:
Polyarthritis
Carditis
Subcutaneous nodules
Erythema marginatum
Sydenham chorea
150
Gram positive cocci in chains,
catalase negative, alpha
hemolytic, optochin sensitive
and bile soluble. Positive
Quellung reaction
Streptococcus pneumoniae
151
Gram positive cocci in chains,
catalase negative, gamma
hemolytic, no growth in 6.5%
NaCl
Streptococcus bovis
152
Gene that mediates methicillin
resistance in
S. aureus
mecA gene
153
Sequestered focus of
osteomyelitis caused by S.
aureus arising in the
metaphyseal area of a long
bone
Brodie abscess
154
In Ritter disease, separation of
epidermis happens at what
layer?
Stratum granulosum
155
A case of fever, hypotension,
strawberry tongue,
desquamating rash and multi -
organ involvement (>3) in
patients with history of using
tampon or nasal packing of
epistaxis
Toxic Shock Syndrome
156
Difference in Toxic Shock
Syndrome caused by S. aureus
and S. pyogenes
S. aureus has no site of
pyogenic inflammation and
blood CS negative
157
Toxin that causes Scarlet fever
Erythrogenic toxin
158
Elevated titers suggest
antecedent Streptococcal
pharyngitis
Anti-Streptolysin O
159
Elevated titers suggest
antecedent Streptococcal skin
infection
Anti-DNAse B
160
An 8 year old female presented
to the ER hypotensive and
suddenly went to cardiac
arrest. History revealed that
she had multiple migrating
sites of arthritis, serpiginous
rashes on the trunk and fever
prior to the onset of
hypotension. Pathology report
showed presence of Aschoff
bodies and Anitschkow cells in
the myocardium. What is the
most likely causative agent in
this patient’s condition?
Streptococcus pyogenes
161
Superficial infection extending
into dermal lymphatics
Erysipelas
(Different from Erysipeloid
caused by Eryslipelothrix)
162
Toxin of Staphylococcus that
causes necrosis of the skin and
hemolysis
Alpha toxin
163
Toxin of Streptococcus that
rapidly destroys tissue and
causes Necrotizing Fasciitis
Exotoxin B
164
A case of fever, migrating joint
pains in the knees and
elbows, and has raised
erythematous serpentine-like
lesions on the back with history
of pharyngitis in the past. What
is the most likely diagnosis?
Acute Rheumatic Fever
(due to cross-reacting
antibodies to M-protein)
165
Most common cause of
neonatal pneumonia, sepsis,
and meningitis
Streptococcus agalactiae
166
Pregnant women should be
screened for Group B
Streptococci colonization at
what age of gestation?
35-37 weeks
167
Characteristic sputum of
patients infected with S.
pneumoniae?
Rusty colored sputum
168
Difference between Bacillus
and Clostridium species
Both are spore-forming,
but Bacillus species are
aerobic while Clostridium
species are anaerobic
169
A 30-year-old male was noted
to have a malignant pustule.
Culture showed that the
organism present is gram (+)
bacilli, spore-forming, aerobic
and non-motile.
Bacillus anthracis
170
Most common form of anthrax
Cutaneous anthrax
171
Most severe form of anthrax
Gastrointestinal Anthrax
172
Drug of choice for cutaneous
anthrax
Ciprofloxacin
173
A case of food poisoning after
eating reheated fried rice. What
is the characteristics of this
organism?
Gram (+) spore-forming
bacilli, aerobic, motile
174
A 40-year-old carpenter
sustained a punctured wound
on his right hand a week ago.
He noted to experience muscle
rigidity thus came for consult.
What is the preferred antibiotic
for this case?
Metronidazole
175
What is the mechanism leading
to the patient in the previous
case to develop such
symptoms?
Inhibiting the release of
GABA by cleaving of
synaptobrevin 2
176
Mode of action of botulinum
toxin
Blocking the release of
acetylcholine
177
A 30 year old female suffered
major injuries to her left arm
after a motorcycle accident. She
was brought to the ER due to
high grade fever. Her left arm is
swollen with dark serous fluid
draining from the wound.
Crepitus can also be felt. What
is the most likely causative
agent?
Clostridium perfringes
178
Toxin responsible for gas
gangrene
Lecithinase
179
Agar used for C. perfringens
Egg yolk agar
180
Antibiotics that can cause
pseudomembranous colitis
Clindamycin, 2nd and 3rd
Cephalosporins and
Ampicillin
181
1st step in treating C. difficile
infection
Stop the antibiotic
responsible for the
infection
182
Antibiotic of choice for
treatment of C. difficile
Vancomycin
183
What’s the mechanism of the
exotoxin of C diphtheria
Inhibits protein synthesis
by adding ADP-ribose to
elongation factor 2
184
Culture media of C. diphtheria
Loeffler’s medium or
Potassium tellurite
185
Antibiotic choice for C.
diphtheria
Erythromycin
186
A newborn who was diagnosed
with neonatal sepsis was
admitted in the hospital.
Culture shows a facultative
intracellular rod that exhibits
cold enhancement and a
narrow zone of beta hemolysis.
This organism can be
transmitted by:
-Ingestion of unpasteurized
milk products
-Across placenta or contact
during delivery
187
L. monocytogenes escapes from the phagosome via which toxin?
Listeriolysin
188
A 30yr old man got into a fight
and broke his jaw a few days
ago which now has developed
an abscess with draining pus.
Anaerobic culture showed
molar tooth colonies. What is
the causative agent?
Actinomyces israelii
189
Treatment of choice for Actinomyces Israelli?
Penicillin
190
40yr old HIV patient came
due to chronic cough. PPD
showed a negative result. Fite
faraco stain demonstrated that
organism is weakly acid fast.
Culture showed orange
colonies. What is the causative
agent?
Nocardia asteroides
191
Drug of choice for Nocardia
infection
Co-trimoxazole
192
Gram negative diplococci that
can ferment glucose and
maltose
Neisseria meningitidis
193
Most severe form of
meningococcemia which leads
to bilateral hemorrhagic
destruction of the adrenal
glands
Waterhouse-Friedrichsen
syndrome
194
Function of the capsule of
Neisseria gonorrhea
None that’s why it is not
significant
195
Deficiency of what component
of the immune system
predisposes a patient to
Neisseria infection
Complement 5-9 deficiency
196
A 12-year-old male presents
with flexion of legs and thighs
with passive flexion of neck.
What sign of meningeal
irritation is this?
Brudzinski’s sign
197
Treatment of choice for
Meningococcemia
Penicillin G
198
Prevention is better than cure
that’s why vaccine against N.
meningitidis is available. This
vaccine contains capsular
polysaccharide of what strains
of N. meningitidis?
A, C,Y and W-135
199
A 19-year-old male came in due
to septic arthritis. Gram stain of
the synovial fluid showed gram
negative diplococci. Toxicity of
this organism is mostly due to
what toxin?
Lipooligosaccharide
200
Most common cause of
urethritis and PID. Also the
most common cause of septic
arthritis in sexually active
adults.
Neisseria gonorrhea
201
Treatment of choice for
infections with N. gonorrhea
Ceftriaxone + Doxycycline
202
Gold standard for the diagnosis
of gonorrheal infection
Nucleic acid amplification
test (NAAT)
203
A gram-negative rod with
polyribitol phosphate capsule
that can be cultured using
chocolate agar. It causes
epiglottitis.
Haemophilus influenzae
type b
204
H. influenzae requires what
factors to be able to grow?
X (Hemin) and V (NAD)
205
Satellite phenomenon of H.
influenzae can be observed
around colonies of what
bacteria?
Staphylococcus aureus
206
What phase of pertussis
infection are antibiotics most
effective?
Catarrhal phase
207
Mechanism of action of
pertussis toxin
-Causes ADP ribosylation
-Activates G protein leading
to increase cAMP
208
A 36yr old male was admitted
due to pneumonia associated
with non-bloody diarrhea and
hyponatremia. What is the
most likely causative agent?
Legionella pneumophila
209
Causative agent of Pontiac
fever
Legionella pneumophila
210
Agar used for the isolation of
Legionella pneumophilla
Charcoal yeast extract agar
211
Most common cause of urinary
tract infection
Escherichia coli
212
A 28 year old male who went to
travel to a local region in the
Philippines went to the ER due
to persistent watery diarrhea.
Culture on EMB agar showed
greenish metallic sheen. What
strain of this bacteria is most
likely the culprit?
Enterotoxigenic E. coli
213
A 40yr old male was brought to
the ER due to persistent bloody
diarrhea after eating
hamburger which he bought
from the street. He was noted
to have hemolytic anemia,
thrombocytopenia and uremia.
What is the most likely
causative agent?
E. coli 0157:H7
214
What is the facultative
organism that is predominant
in the large intestine and can be
used as an index of fecal
contamination of a water
sample?
E. coli
215
What is the most predominant
organism of the large intestine?
This organism is considered as
anaerobic.
Bacteroides fragilis
216
Tests used to detect antibodies
against Salmonella in patient’s
serum
Widal test
217
Capsular antigens for bacteria
are labeled as K antigen except
for Salmonella which is labeled
as _________.
Vi antigen
218
Who are at greater risk of
developing osteomyelitis due to
S. cholerasuis?
Patients with sickle cell
anemia
219
The most sensitive diagnostic
modality for Salmonella
infections
Bone marrow culture
220
In cases of chronic carriers of
Salmonella, the microorganism
can usually be isolated at ______.
Gallbladder
221
A 30yr old male was brought to
the ER due to bloody-diarrhea,
abdominal pain and confusion.
Culture of the stool showed
non-lactose fermenting gram
negative rods which are nonmotile
and does not produce
H2S. What is the causative
agent?
Shigella dysenteriae
222
Mode of action of Subunit A of
Cholera toxin
ADP ribosylation leading to
stimulated Gs protein
which increases cAMP
223
Agar of choice for the isolation
of Vibrio cholerae
Thiosulfate Citrate Bile Salt
Sucrose agar
224
Treatment of choice for Cholera
Fluid and electrolyte
replacement
225
The strain of Vibrio that led to a
pandemic of Cholera in the past
is _________
Vibrio cholerae 01 biotype
El Tor
226
A 30-year-old male came to the
ER due to watery diarrhea
associated with abdominal
cramps, vomiting, and low
grade fever. Upon taking
detailed history, it was noted
that symptoms develop after
eating raw seafood. What is the
causative agent?
Vibrio vulnificus
227
Small, motile, non-spore
forming curved microaerophilic
bacilli that is associated with
GBS
Campylobacter jejuni
228
Agar of choice for C. jejuni
Skirrow agar
229
Triad of Reiter Syndrome
Urethritis, Uveitis and
Arthritis
230
Triple therapy for H. pylori
includes:
Amoxicillin +
Clarithromycin + PPI
231
Bacteria’s that are considered
as Urease positive
Proteus mirabilis
Klebsiella pneumoniae
Helicobacter pylori
Ureaplasma urealyticum
232
Cancers that are associated
with H. pylori
Gastric carcinoma
MALT lymphomas
233
A 59-year-old alcoholic male
came to the ER due to
productive cough with mucoid
bloody sputum. Gram stain
revealed large capsules. What is
the most likely etiologic agent?
Klebsiella pneumoniae
234
Struvite stones formed by
Proteus mirabilis are mainly
composed of ______________.
Magnesium-ammonium-phosphate
235
A 29-year-old female came in
due to recurrent urinary tract
infection. Diagnostics revealed
she has nephrolithiasis. Culture
was done which showed gram
negative rods urease positive
with swarming motility. What
is the most likely etiologic
agent?
Proteus mirabilis
236
Soft tissue infection on burn
patients is most likely caused
by?
Pseudomonas aeruginosa
237
Mechanism of action of
exotoxin A of P. aeruginosa
Tissue necrosis and
inactivation of elongation
factor 2
238
Pleomorphic aerobic gramnegative
bacillus that is multidrug
resistant and is commonly
isolated from hospital
environment and hospitalized
patients
Acinetobacter baumanii
239
Most common reservoir of F.
tularensis
Rabbits
240
A 30-year-old male came in due
to sudden onset of fever, chills
and multiple painful lymph
nodes. Gram stain showed a
gram-negative rod with safety
appearance
Yersinia pestis
241
What is the vector for the
transmission of Y. pestis
Oriental rat flea (Xenopsylla
cheopis)
242
A 28 year old male develops
cellulitis after he was bitten by
his neighbor’s cat. What is the
most likely dominant organism
involved in the infection?
Pasteurella multocida
243
Causative agent of cat scratch
fever is
Bartonella henselae
244
A gram-negative rod that
causes skin and bone infections
associated with human bites.
Eikenella corrodens
245
Causative agent for the disease
called Pinta
Treponema carateum
246
What test is useful for CNS
syphilis?
VDRL
247
Which of the following can be
seen in secondary syphilis?
Condyloma Lata
248
What part is usually affected in
aortitis caused by syphilis?
Vasa vasorum
249
Which test can be used for
monitoring of treatment of
syphilis and can also be used a
test of cure?
RPR, VDRL
250
Triad of Weil Syndrome
Jaundice, bleeding and
uremia
251
Influenza like symptoms few
hours after receiving Penicillin
for treatment of Leptospirosis
is called _______.
Jarisch-Herxheimer
reaction
252
Treatment of choice for mild
leptospirosis
Doxycycline
253
Characteristic finding in chest
Xray if there is pulmonary
involvement in a patient
diagnosed with leptospirosis
Snow-flake lesions
254
Largest medically important
spirochete that is the causative
agent of Lyme disease
Borrelia burgdorferi
255
Characteristic dermatologic
finding in patients on stage 1 of
Lyme disease
Erythema chronicum
migrans
256
Most important virulence
factor of Mycobacteria
Cord factor
257
The most common site of
extrapulmonary tuberculosis
Lymph node
(Scrofula)
258
Pathognomonic finding of
Miliary tuberculosis
Choroidal tubercles
259
Diagnostic tool for latent
tuberculosis that is not affected
by prior BCG vaccination or
infection with nontuberculous
mycobacteria
Interferon Gamma Release
Assays
260
Mechanism of resistance
against rifampicin
rpoB gene mutation
261
Tuberculin skin test
demonstrates what type of
hypersensitivity reaction?
Delayed (Type 4)
262
M. leprae can be cultured using
Mouse foot pad or in the
armadillo
263
Lepromin skin test would be
positive on_____.
Tuberculoid Leprosy
264
Treatment of choice for
Erythema nodosum leprosum
Thalidomide
265
Most common cause of atypical
pneumonia. This is bacteria has
sterol in membrane and can
cause for the body to form cold
agglutinins.
Mycoplasma pneumoniae
266
Round to oval cytoplasmic
inclusion bodies near the nuclei
of conjunctival epithelial cells
in trachoma
Halberstadter-Prowazek
inclusion
267
A 22 year old sexually active
female presented with
unilateral painful inguinal
lymphadenopathy. Extensive
enlargement of chains of
inguinal nodes are noted above
and below the inguinal
ligament. What is the most
likely etiologic agent?
Chlamydia trachomatis
types L1-L3
268
Treatment for Chlamydia
Doxycycline 100mg BID for 7
days
269
Types of C. trachomatis associated
with trachoma
Types A-C
270
Types of C. trachomatis that causes
genital tract infections and is
associated with Reiter syndrome
Types D-K
271
Types of C. trachomatis associated
with Lymphogranuloma venereum
Types L1-L3
272
A type of rickettsial disease that
does not present with fever or rash,
has a chronic onset and has the
highest mortality
Q fever (caused by Coxiella
burnetii)
273
Treatment of choice for Rickettsial
infections
Doxycycline
274
Drug that is contraindicated in
patients with Rickettsial infection
because they stimulate Rickettsial
growth
Sulfonamides
275
A 40-year-old female with grayish
vaginal discharge where wet
mount showed stippled epithelial
cells being covered by
microorganism. The condition
most likely described is_______.
Bacterial Vaginosis
276
A gram-negative rod that is
associated with painful genital
ulcers.
Haemophilus ducreyi
