Microbiology Flashcards
1
Q
virulence factor M protein function
A
molecular mimicry, similar epitope to human protein. ?AI response of ARF. group A streptococcus
2
Q
Q fever - what bug?
A
coxiella burnetii
3
Q
McConkey’s Agar cultures….
A
- Klebsiella*
- E Coli*
- Enterobacter*
Bile salt-containing which inhibits growth of most gram +ve organisms
4
Q
2 topical antifungals for infection?
A
itraconazole, fluconazole
5
Q
VDRL tests for what disease? what is the sensitivity?
A
syphillis 80%
6
Q
cell wall component unique to Gram -ve bacteria?
A
- endotoxin/LPS
- porin
- periplasmic space
7
Q
food poisoning giving constipation followed by a flaccid paralysis suggets?
A
clostridium botulinum
8
Q
Monospot test +ve suggests what?
A
heterophile antibodies present in serum, represents EBV (HHV-4) infection.
Important negative in suspected CMV (HHV-5)
9
Q
parainfluenza, mumps, RSV, metapneumovirus, measles are all…
A
paramyxoviridae
10
Q
hippie mother, orchitis and aseptic meningitis, followed by pancreatitis should suggest…
A
Mumps
11
Q
the transfer of vancomycin resistance from enterococcus to other bacteria occurs through which genetic process? describe…
A
transposition gene flanked by two ‘transposon’ sequences in a plasmid that can be cleaved and integrated into bacterial chromosomes
12
Q
unique bacterial structure of Bacillus anthracis
what is the anthracis toxin and how does it work
A
only bacterium with a polypeptide (D-glutamate) capsule
oedema toxin - mimics adenyl cyclase (increasing cAMP) leading to haemorrhage (haemorrhagic mediastinitis) and oedema (bloody pleural effusion, shock)
13
Q
myobacterium sulfatide is what? function?
A
surface glycolipid prevents phagocytosis - granuloma formation
14
Q
vibrio is…
A
enteric gram -ve bacillus
15
Q
pityriasis versicolor is caused by which bug?
A
malassezia spp. not strictly a dermatophyte, despite being called tinea sometimes. malassezia is a yeast-like fungus
16
Q
what is going on?
what else is this baby at risk of? (4)
A
congenital rubella syndrome
‘blueberry muffin’ - dermal extramedullary haematopoesis in response to infection. Confirm with serum IgM vs Rubella (cannot be mother’s)
deafness, blindness/cataracts, microcephaly and congenital cardiac abnormality
17
Q
CSF findings in viral meningitis
(OP, cell type, protein, glucose)
A
OP - normal
cell type - lymphocytes
protein - normal/up
glucose - normal
18
Q
genital ulcer - painless, progressive red ulcerative leasions with a wavy border (serpinginous). No lymph nodes.
diagnosis (bug)? diagnostic test?
A
granuloma inguinale (donovanosis) - Klebsiella granulomatis
gram strain and culture (hard to get), biopsy with looking for Donovan bodies.
19
Q
What medium is used for Corynebacterium dyptheriae?
A
Cysteine-Tellurite agar
20
Q
what are three mechanisms for aminoglycoside resistance?
A
aminoglycoside-modifying enzymes
mutated ribosomal subunit &/or porin proteins
21
Q
staphylococcus aureus produces what colour pigment?
A
yellow aureus = ‘gold’
22
Q
bordatella is…
A
respiratory gram -ve bacillus
23
Q
clostridium is…
A
gram +ve bacillus
24
Q
does and endotoxin or an exotoxin have greater antigenicity? (i.e. versus which do we make antibodies)
A
exotoxin - induces high-titre antibodies called antitoxins
25
parasite association haematuria, SCC bladder
schistosoma haematobium
26
which type of bacteria have an outer membrane?
Gram -ve
27
neonatal - HSM, jaundice, petichiae/purpura, chorioretinitis, SFGA & microcephaly
suggests what congenital infection? what is at risk? Rx?
congential CMV
most newborns will be asymptomatic but 15% will develop progresive senorineural hearing loss.
Ganciclovir - prevent hearing loss and dev delay
28
which HHV - herpetic whitlow, herpes labialis, keratoconjunctivitis?
HHV-1
29
*H pylori* treatment?
**triple therapy**
omeprazole, amoxicillin
*& either* metronidazole *or* clarithromycin
30
how would you get *campylobacter jejuni*? (2)
faeco-oral transmission from:
1. domestic animals
2. undercooked food/poultry
31
what bug requires factors X and V for growth?
*Haemophilius influenzae*
32
what is prostitute's pupil?
Argyll-Roberson pupil - constricts to accommodation but not light reaction sign of tertiary neurosyphillis
33
which bug is likely to produce a biofilm around a catheter or prosthetic device in situ?
S epidermidis
34
pseudomonas aeruginosa produces what colour pigment?
blue-green
35
catalase tests between which gram +ve bacteria? which is catalase +ve?
staphylococcus and streptococcus/enterococcus staphylococcus is catalase +ve
36
classification of parvovirus B19?
nonenveloped, single-stranded DNA virus
37
salmonella vs shigella flagella?
salmonella (salmon swim)
38
what infection are cryogolbulins commonly associated with?
HCV
39
a double-stranded, non-enveloped DNA virus causing hydrops fetalis (& IUD) or aplastic crisis in sickle cell disease is...
parvovirus B19
40
which are the medically important paramyxoviridae?
PaRaMyxovirus
P - parainfluenza
R - RSV treat with Ribavirin
M - mumps, measels
41
elderly meningitis bugs (2)
S pneumoniae, Listeria
42
group B, beta-haemolytic strep is...
strep agalactiae
43
most common complication of this?
post-herpetic neuralgia
44
enterococcus is...
gram +ve coccus
45
what bugs are positive for haemadsorption on blood cell culture?
Influenza and parainfluenza - they have haemaglutinin (H) surface glycoprotein that have high affinity for erythrocytes
46
what bugs are associated with dog bites?
*Pasteurella multocida* (mouse-like odour on culture)
Streptococci
*Staph aureus*
47
what are the mechanisms of action for ribavirin?
overall = interferes with duplication of viral genes
ribavirin becomes ribavirin mono-/di-/tri-phosphate in the cell
* substitutes into viral RNA causing RNA-dependent viral gene replication hypermutation which is lethal.
* depletes intracellular GMP/GTP
* directly interferes with viral RNA-dependent RNA polymerase
* immunomodulation favouring CD8+ cytotoxic cells
48
bugs for PID
Chlamydia trachomatis (subacute, often undiagnosed)
neisseria gonorrhoeae (acute)
49
what is the unique resistance mechanism to quinolones?
mutated DNA gyrase
50
Grma -ve bacillus, non lactose fermenting, oxidase -ve.. what's left? (4) how to tell apart?
salmonella, proteus (makes H2S) shigella, yersinia (no H2S)
51
gam +ve rod with metachromatic granules and +ve Elek test
corynebacterium diptheriae
52
high fever in infant (6 - 36 months) followed by diffuse maular rash starting on the trunk and spreading to the head and face suggests what disease?
What bug?
roseola infantum (erythema subitum)
HHV-6 (less commonly HHV-7)
53
classification of HSV?
double-stranded DNA, enveloped
54
what bug is this? Most common disease caused in immunocompromise?
Rx (3)?
Cryptococcus neoformans
fungal meningioencephalitis
amphotericin B and flucytosine (followed by fluconazole if meningitis)
55
yersinia is...
enteric gram -ve bacillus
56
time frame of N and V with bacillus cereus ingestion?
1 - 5 hours (preformed cereulide toxin)
57
major complication of neonatal N gonorrhoeae infection? Rx?
conjunctivitis --\> blindness erythromycin eye drops
58
what is the correct antimicrobial for and when do you start prophylaxis in HIV against:
* PCP
* *toxoplasma gondii*
* *mycobacterium avium* complex
* *Histoplasma capsulatum*
* CD4+ \< 200 - co-trimoxazole
* CD4+ \< 100 - co-trimoxazole
* CD4+ \< 50 - azithromycin
* CD4+ \< 150, endemic area - itraconazole
59
listeria Rx
ampicillin
(+ gentamycin if immunocompromised)
60
bacillus cereus diarrhoea has what appearance?
8 - 18 hours following ingestion, watery non-bloody diarrhoea with GI pain
61
an asthmatic/CF patient with eoisinophilia, elevated serum IgE and recurrent lung infiltrated leading to bronchiectasis
disease?
bug?
allergic broncopulmonary aspergillosis
aspergillus fumigatus
62
genital ulcer - deep, purulent, painful. suppurative lymphadenitis
what disease? diagnostic test?
chancroid - *haemophilus ducreyi*
Gram stain and culture of swab. PCR.
63
what bug likely causes epiglotitis?
what is it's major virulence factor and target of its vaccine?
HiB
polyribosylribitol phosphate
64
definitive diagnosis of HSV-1 encephalitis?
CSF PCR
65
major staph epidermidis virulence factor
exopolysaccheride secretion forming biofilm - typically causes foreign body infection such as IV catheter or ventriculoperitoneal shunt
66
which gram -ve, oxidase +ve organism grown in alkaline medium?
Vibrio
67
ventilator-associated pneumonia or contact lens-associated keratitis is usually which bug?
pseudomonas aeruginosa
68
this is specific finding of what childhood virus?
What are these called?
If this was on the palate, how does the answer change?
Measles
Koplik spots
Would be Rubella (german measles), Forchheimer spots. Lymphadenopathy more likely
69
top 3 bugs for UTI
E coli
Staph saprophyticus (sexually active)
Klebsiella (urease-positive so assoc with MAP stones)
70
PCP pneumonia treatment & prophylaxis?
Rx - co-trimoxazole (TMP-SMX), inhaled pentamidine, atovaquone
prophylaxis - 1st line = co-trimoxazole, sulfa allergy = dapsone
(when HIV CD4+ T cell count \<200 cells/mm^3)
71
erythema nodosum/multiforme, with arthralgia and risk of meningitis (fungus)?
coccidioidomycosis
72
what receptor does EBV use to enter cells?
CD21
73
cellular mechanism of pertussis toxin
inhibition of Gi, disinhibition of cAMP production in the cell, prevents successful phagocytosis
74
empiric treatment of CoNS until sesnitivities are back from the lab? what is this bug likely to be resistant to?
vancomycin - blocks gram +ve wall synthesis without being pen/cef class
methcillin-resistance, with *mecA* gene package (alteration to PBPs) - accompanied by resistnace to fluoroquinolones and clindamycin
75
What bug produces biofilms in otitis media?
*Haemophilius influenza* (nontypable)
76
shigella is...
enteric gram -ve bacillus
77
staphylococcus is...
gram +ve coccus
78
pseudomonas is...
enteric gram -ve bacillus
79
virulence factor protein A function?
binds Fc region of IgG preventing opsonisation or phagocytosis.. S aureus
80
Propionobacterium acnes is...
gram +ve bacillus
81
which leprosy has a predominantly cell-mediated (Th1) response?
tuberculoid
82
legionella is...
respiratory gram -ve bacillus
83
Gram -ve bacillus, non lactose fermenting, oxidase +ve..
pseudomonas
84
INF-gamma primarily secreted by what cells? function (4)?
Th1 lymphocytes
increase macrophage phagocytosis and NK cell killing. Increase MHC expression on all cell types. Inhibit Th2 cell proliferation.
85
what bugs are associated with human bites?
* Staphylococcus aureus;* Streptococci
* Eikenella corrodens*
and a mixture of other anaerobes
86
proteus, cryptococcus, h pylori, ureaplasma, klebsiella, s epidermidis, S saprophyticus are all...
urease-positive organisms
87
chlamydia is...
pleomorphic without cell wall
88
3 bugs for HIV-associated oesophagitis? defining finding on OGD
1. *candida albicans* - pseudomembranes
2. HSV-1 - punched-out ulcers
3. CMV - linear ulceration
89
campylobacter is...
enteric gram -ve bacillus
90
is endotoxin or exotoxin(s) more heat-stable?
endotoxin.. induces fever so must be fine in heat
91
granulomatosis infantiseptica is caused by what bug?
listeria monocytogenes
92
Rocky Mountain Spotted Fever - what bug? How is it spread?
rickettsia rickettsii dog tick
93
bronchiolitis in under 2 y/o - most common bug?
RSV
94
cell wall component unique to Gram +ve bacteria?
lipoteichoic acid
95
Mycobacterium is...
gram +ve bacillus
96
in a newborn - chorioretinitis, hydrocephalus and intracranial calcifications
congenital toxoplasmosis
97
give a few (5 classes) Abx good for *pseudomonas*
(Tazocin) piperacillin
(3-4th gen cephalosporin) cefepime, ceftazidime
(aminoglycosides) amikacin, gentamicin
(fluoroquinolones - for RTI) cipro, levofloxacin **not moxi**
(carbapenems) meropenem
98
a dilated cardiomyopathy, apical atrophy, megacolon and megaoesophagus suggests what bug? disease called?
trypanosoma cruzi American trypanosomiasis/Chagas disease
99
diagnostic test for histoplasmosis?
blood/urine antigen
100
salmonella is...
enteric gram -ve bacillus
101
what receptor does HIV use to enter cells?
CD4
then needs CXCR4 or CCR5
102
which are the bugs that pass from mother to child?
ToRCHHeS
Toxo, rubella, CMV, HIV, Herpes (HSV-2), syphilis
103
aerobic gram +ve bacillus? (2)
listeria bacillus
104
risus sardonicus is associated with which condition? which bug?
tetanus clostridium tetani
105
mycoplasma is...
pleomorphic without cell wall
106
multinucleated trophozoite found in stool/cysts
giardia lamblia
107
what is appropriate CMV prophylaxis in post-lung transplant patients?
what family is CMV and what is the viral classification?
valganciclovir
Herpes virus - DNA, double stranded, enveloped
108
bacillus is...
gram +ve bacillus
109
urease-positive organisms are associated with what condition?
MAP nephrolithiasis
110
species responsible for hot tub folliculitis?
pseudomonas aeruginosa
111
novobiocin tests between which bacteria? which is sensitive?
staph epidermidis and staph saprophyticus staph epidermidis is sensitive
112
what is the mechanism for rifamycin resistance?
mutated RNA polymerase
113
what are the mechanism of actions of the antimycobacterial drugs?
side effects?
R - mRNA synthesis - GI, **r**ash, **r**ed (orange) secretions, cytopenia
I - mycolic acid (cell wall) synthesis inhibition - neurotoxic (B6 adjunt) & hepatotoxic
P - unclear - hepatotoxic & hyperuricaemia
E - inhibition of arabinosyl transferase (?) - optic neuropathy
114
botulinum toxin - mechanism of action and 4 D symptoms
SNARE protease, inhibiting ACh release at NMJ. Flaccid paralysis. D - diplopia, dysphagia, dysarthria, dyspnoea
115
What bug produces biofilms on contact lenses?
*Pseudomonas aeruginosa*
116
decreased gastric acidity (increased pH) makes you more sensitive to which gram -ve organisms?
shigella and vibrio
117
CSF findings in fungal meningitis
| (OP, cell type, protein, glucose)
OP - up
cell type - lymphocytes
protein - up
glucose - down
118
gram -ve bacillus, lactose fermenting bacteria are... (3)
tested using McConkey's McConKEE K - Klebs E - E Coli E - Enterobacter
119
for Lyme disease features, what does FACE stand for?
F - facial nerve palsy (Bell's) A - arthralgia C - carditis E - erythema multiforme
120
what CD4+ cell count inidcates progression to AIDS?
\< 200 CD4+ cells/mm^3
| (500 - 1500)
121
neisseria is...
gram -ve coccus
122
what bugs can cause impetigo?
*staph aureus*
group A strep (*Strep pyogenes*)
123
124
*giardia lamblia* treatment?
metronidazole
125
what receptor does CMV use to enter cells?
integrins (heparin sulphate)
126
what extracellular molecule does strep viridans have the capacity to adhere to? how is this clinically relevant?
fibirin-platelet aggregations
*Strep* viridans only causes endocarditis on previously damaged valves. *Staph* *aureus* can adhere to undamaged valve.
127
streptococcus is...
gram +ve coccus
128
Kala-azar is also known as? bug? blood findings?
visceral leishmaniasis leishmania donovani - pancytopenia
129
virulence factor IgA protease function?
cleave IgA, allowing mucosal colonisation S pneumoniae, H influenzae, N meningitidis
130
on VE - thin white, fishy discharge with no erythema
Clue cells present, alkalinisation
disesae? Bug? Rx?
bacterial vaginois - *Gardnerella vaginalis*
metronidazole
131
what receptor does parvovirus B19 need to enter cells?
P antigen (globoside) expressed on erythrocytes
132
during infectious mononucleosis, what advice is given to patients?
what bug?
what medication should be avoided?
no contact sport - risk of splenic rupture
Ebstein-Barr virus (HHV-4)
Amoxicillin - associated rash
133
on VE - cervical inflammation, frothy, foul smelling, yellow discharge
HVS - motile bugs, alkalinisation
Rx?
trichomonas vaginalis vaginitis
metronidazole, treat partner
134
how to tell N meningitidis from N gonorrhoeae?
maltose test +ve = meningitidis -ve = moraxella or N gonorrhoeae
135
how to shigella and salmonella invade the GI tract?
through M cells in the Peyer patches
136
first line treatment for any leprosy? what is added for lepromatous leprosy?
dapsone and rifampin add clofazimine
137
What bug produces biofilm on dental plaques?
*Strep* viridans (*mutans* and *sanguinis*)
138
what is the mechanism of action for acyclovir?
nucleoside ananlog (dGTP)
acyclovir is activated into active compound, incorporated into DNA through viral DNA polymerase
when incorporated, DNA polymerisation terminates and replication fails.
139
what receptor does rabies use to enter cells?
nAChR
140
GI bugs with a very low ID(50) - infectious dose required to cause disease in 50% of affected individuals. (4)
Shigella
Giardia
Campylobacter jejuni
Entamoeba histolytica
roughly 10 - 1000 organisms can cause disease (so 10^2-10^4)
141
which leprosy is lethal?
lepromatous
142
anaerobic gram +ve bacillus? (2)
clostridium propionibacterium
143
trophozoite with engulfed RBCs
entamoeba histolytica
144
what does capsofungin do?
when is it used?
non-competitive inhibitor of beta-glucan synthase
*candida* resistant to -azoles
145
what does viral RNase H do?
removes viral RNA primer from newly synthesized DNA
blocking RNase is useful in treating retroviruses (HIV).
146
klebsiella is...
enteric gram -ve bacillus
147
CSF findings in bacterial meningitis
| (OP, cell type, protein, glucose)
OP - up
cell type - PMNs
protein - up
glucose - down
148
anti-fungal that punches holes in membrane wall?
amphotericin B
149
bacterodies is...
enteric gram -ve bacillus
150
*M tuberculosis* that grows in 'serpentine cords' has what?
What is its function? (3)
Cord factor - a virulence factor associated with ability to cause disease
Cord factor = inactivates neutrophils, damages mitochondria and stimulates release of TNF-alpha
151
mortalilty rate in asplenic sepsis
50%
152
major virulence factor for *strep pneumoniae*
what are the other virulence factors (3)?
Polysaccheride capsule with \>90 different types
IgA protease, pneumolysin (creates pores in cell membrane) & adhesin (adhesion to epithelial cells)
153
pseudomonas, strep, haemophilus, influenza neisseria, E coli, salmonella and Klebsiella are all...
encapsulated organisms opsonised and removed by the spleen, so give HbS patients H influenza, S Pneumoniae and N meningitidis vaccines
154
what other than treponema pallidum can give a +ve VDRL?
'VDRL' V - viral, EBV/HxV D - drugs R - rheumatic fever L - lupus, leprosy
155
N gonorrhoeae Rx
ceftriaxone (+ doxy for possible chlamydial infection)
156
proteus is...
enteric gram -ve bacillus
157
a Gohn complex consists of what?
unilateral hilar adenopathy AND a Gohn focus (site of primary infection)
158
intraerythrocytic pleomorphic inclusions on blood smear suggests what bug? vector for transmission? which other diseases are carried by this vector?
* Babesia microti*
* Ixodes* tick (deer tick from NE america)
* Borellia burgdorferi* (Lyme disease) & *Anaplasma spp.* (human granulocytic anaplasmosis)
159
Listeria is...
gram +ve bacillus
160
sickle cell disease and osteomyelitis - what bugs?
*salmonella* and *staph aureus*
Remember *salmonella* is encapsulated with Vi(rulence) antigen that protects from opsonization
161
pit versicolor Rx
selenium sulfide (SelSulf) + oral/topic antifungal in large quantities
162
parasite association vitamin B12 deficiency
diphyllobothrium latum
163
what bug forms biofilms on prosthetic devices/IV catheters?
*steph epidermidis*
164
what bug causes lyme disease?
borellia burgdorferi
165
alpha-haemolytic, optochin resistant strep is...
strep viridans type (S mutans and S mitis)
166
MRSA commonly colonises what area of the body?
anterior nares
167
bartonella is...
zoonotic gram -ve bacillus
168
in mycoplasma pneumoniae LRTI, what is the treatment? What will not work? Why?
doxy, macrolides or fluroquinolone
beta-lactams
mycoplasma = pleomorphic w/o cell wall
169
trichomonas vaginalis Rx
metronidazole for patient and partner
170
which is the most important E Coli virulence factor in each of these presentations?
Neonatal meningitis
bloody/watery gastroenteritis (2 different ones)
UTI
NNM - K capsule, evade recognition in the blood to allow haematogenous spread
bloody gastroenteritis - verotoxin (shiga-like toxin)
watery gastroenteritis - HS/HL enterotoxin
UTI - P fimbriae allow adhesion to uroepithelium
171
a budding yeast with a thick capsule, stained by mucicarmine/india ink is called what? Who does it infect? Typical presentations (2)?
cryptococcus neoformans
immunocompromised
cryptococcal meningioencephalitis, usually starts in lung though
172
antifungal for systemic use?
amphotericin B
173
gram +ve, catalase +ve, coagulase -ve (2)
staph saprophyticus and staph epidermidis
174
salmonella vs shigella Abx shortens duration of symptoms
shigella
175
Infant meningitis (3)
S pneumoniae, N meningitidis, HiB
176
A Zeihl-Neelsen stain will be +ve for what, other than TB?
protozoa, e.g. cryptosporidium
177
what virus causes condylomata acuminatum? common name for this condition?
where else does this virus affect?
HPV 1, 2, 6 and 11
anogenital warts
stratified squamous epithelium of respiratory tract = **true vocal cords**
178
meningitis and unpasteurised dairy
Listeria
179
two spore-forming bacteria
bacillus (anthrax, food poisoning) clostridium (pseudomembranous colitis, botulinum, tetanus)
180
how would you get *vibrio parahaemolyticus*?
contaminated shellfish
181
gamma haemolytic bacteria?
enterococcus
182
gram +ve, coagulase +ve, catalase +ve?
staph aureus
183
endemic typhus - what bug? How is it spread?
*Rickettsia typhi, Rickettsia prowazekii*
Fleas
184
E coli is...
enteric gram -ve bacillus
185
tetanospasmin - mechanism of action?
SNARE protease, inhibiting GABA/glycine inhibitor spinal neurons, disinhibited excitatory motor neurons, spastic paralysis
186
salmonella, neisseria, brucella, myobacterium, listeria, yersinia, legionella are all...
facultative intracellular bacteria
187
what does HDV need HBV co-infection for?
coating the HDAg internal polypeptide with HbsAg so that it can subsequently gain access to other hepatocytes
188
croup - most common bug?
parainfluenza virus
189
if not through a cat, how is toxoplasma transmitted?
Contaminated food
190
*Neisseria* are cultured on what medium? what does it contain and what is the purpose of each?
selective, Thayer-Martin (VCN) medium.
V - vancomycin - kills gram +ve
C - colistin - kills non-*Neisseria* gram -ve
N - nystatin - kills fungi
191
newborn meningitis bugs (birth canal)
GBS
E Coli
Listeria
192
what is a fungus smaller than an RBC that hides within macrophages?
histoplasma
193
what antibiotic is used for intrapartum GBS prophylaxis?
penicillin G (or ampicillin)
194
positive Tzanck test suggests which bugs are present?
what is the Tzanck test?
HSV-1, HSV-2, VZV (HHV-3)
smear of opened skin vesicular fluid to look for multinucleated giant cells
195
moraxella is...
gram -ve coccus
196
what bug causes syphillis?
treponema pallidum
197
people in close contact, low-grade fever, unremarkable physical findings, infiltrates on CXR, culture only works with cholesterol
disease name? bug? Rx (3)? haematological association?
Walking pneumonia
*Mycoplasma pneumoniae*
**macrolide**, tetracyline, fluoroquinolone (tetra/fluoro not for kids)
production of IgM cold agglutinin
198
a Hawaiian surfer has coryza, calf pain, jaundice, conjunctivitis without exudate and photophobia. what bug?
leptospirosis from leptospira interrogans
199
this is called? what bug? who gets it? sign of what underlying pathology?
ecthyma gangrenosum
*pseudomonas gangrenosum*
critically ill patients (& renal transplant)
*pseudomonas* septicaemia
200
treatment of Chagas disease? (bug?)
nifurtimox
trypanosoma cruzi
201
*c diff.* toxins with mechanism?
treatment for 1st line and recurrent
**Toxin A** (enterotoxic) and **Toxin B** (Cytotoxic). Both inactivate Rho-regulatory proteins leading to disruption of actin **cytoskeleton**, cell death.
Rx - metronidazole or oral vancomycin.
Recurrent Rx - fidaxomicin, faecal transplant
202
the plague is what bug? How is it spread?
yersinia pestis rat and prairie dog fleas
203
rickettsia is...
pleomorphic without cell wall
204
Bariella is...
gram -ve spiral
205
parasite association biliary tract disease, cholangiocarcinoma
clonorchis sinensis
206
what receptor does RSV use to enter cells?
ICAM-1
207
what animal gives you psittacosis?
parrot & other birds
## Footnote
*chlamyophila psittaci*
208
blood agar with bile salts and hypertonic saline is the culture medium used to tell which gram +ve organisms apart?
used to tell apart the gamma-haemolytic gram +ve cocci.
* bile salts will grow group D *Strep* (*bovis/equinus*)
* bile salts and hypertonic saline will grow *Enterococci* (*faecalis* etc..)
209
sputum gram stain showing many neutrophils with few/no organisms.
what bug?
*Legionella*
210
what bug can mimic appendicitis?
yersinia diarrhoea with RIF pain from mesenteric adenitis/terminal ileitis
211
lactobacillus is...
gram +ve bacillus
212
helicobacter is...
enteric gram -ve bacillus
213
this is a patchy, hypopigmented skin lesion without sensation. What is the disease called?
Caused by which bug?
Tuberculoid leprosy
## Footnote
*mycobacterium leprae*
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a fungus much larger than RBCs filled with its own endospores?
coccidioides
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why should pregnant women avoid unpasteurized cheeses and cold deli meats?
Listeria monocytogenes infection listeria - transplacental transmission, amnionitis, spontaneous abortion. listeria grows best 4 - 10 degC, so refrigeration makes it worse
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non-bacterial pneumonia picture.
Bronchioalverolar lavage with silver stain shows septate hyphae
aspergillus fumigatus
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epidemic typhus caused by what bug? How is it spread?
rickettsia Prowazekii
human to human by body louse
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parasite association brain cysts & seizures
neurocysticercosis (taenia solium)
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Rx *H influenzae*
options for chest and meningeal infections
co-amox for resp/mucosal
ceftriaxone for meningitis
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which is the most frequent anti-HIV drug to develop resistance against and what do we do to stop this?
what is the gene that is implicated in this resistance mechanism?
NRTIs; always give two at the same time
*Pol* - reverse transcriptase
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which infectious diseases present with rash on the palm and soles?
'CARS' Coxsackievirus A Rocky mountain spotted fever (rickettsia rickettsii) 2ary syphilis
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Rx of H pylori (triple therapy)
**A**ntibiotics **C**ure **P**ylori
* **a**moxicillin (penallergic = metro)
* **c**larithromycin
* **P**PI
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enterobacter is...
enteric gram -ve bacillus
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Giemsa stains +ve for... Certain Bugs Really Try Patients
Chlamydia Borrelia Rickettsia Trypanosomes (Chagas disease) Plasmodium
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parasiste association microcytic anaemia
ancylostoma, necator
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molluscum contageosum - what bug?
poxvirus
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what are 2 resistance mechanisms against vancomycin?
1. mutated peptidoglycan cell wall
2. impaired influx/increased efflux
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gram +ve haemolysis test tells between which bacteria?
streptococcus and enterococcus
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group A, beta-haemolytic strep is...
strep pyogenes
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what does flucytosine anti-fungal do?
inhibits nucleic acid synthesis
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which type of bug commonly causes disease in CGD?
why?
what bugs? (5)
catalase-positive
bugs produce hydrogen peroxide normally, so within phagolysosome will kill themselves. bugs with catalase can indefinitely survive in the phagolysosome.
*Staph aureus, Burkholderia cepacia, Serratia marcescens, Nocardia, Aspergillus*
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leptospira is...
gram -ve spiral
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what bugs are associated with a cat bite/scratch?
* Pasteurella multocida* (mouse-like odour on culture)
* Bartonella henselae* - cat scratch disaese with classic lymphadenitis
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species responsible for erythema gangrenosum?
pseudomonas aeruginosa
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salmonella vs shigella sensitive to gastric acid?
salmonella, so need to have large inoculation in order to get sick
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major complication of HHV-1
temporal lobe epilepsy
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on VE - thick white discharge wih inflammation
HVS - normal pH, pseudohyphae
Rx?
vulvovaginal candidiasis
triazole antifungals
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aspiration lobar pneumonia in alcoholics likely to be which bug?
Klebsiella
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which are the most common encapsulated organisms? (to watch out for in asplenism)
SHiN
s pneumoniae
HiB
N meningitidis
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what medication can improve the coure of measles? (not antimicrobial)
what are the 3 major complication of measles?
vitamin A
1. subacute sclerosing panencephalitis (SSPE)
2. encephalitis (1:2000)
3. giant cell pneumonia
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treatment for sarcoptes scabiei?
permethrin cream
wash/dry everything in the house
treat whole family
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which leprosy has a predominant humoral response (Th2)?
lepromatous
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most serious consequence of neonatal HSV-2 infection?
meningioencephalitis
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a fungus much larger than RBC with a captain wheel formation during budding
paracoccidiodes
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malignant otitis externa most likely caused by what bug?
what toxins does this bug have?
*pseudomonas aeruginosa*
exotoxin A and endotoxin
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What bug is this? pathoG phrase to describe?
CMV
'owl eye' inclusion of infected cell
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treatment to **prevent recurrence** of genital herpes simplex flare?
continuous oral valacylavir daily.
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parasite association hydatid (liver) cytsts
echinococcus granulosus
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which gram -ve, oxidase +ve organism grows at 42 degC?
campylobacter
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Rx typhoid fever? distinguishing clin features?
ceftriaxone or fluroquinolone 'rose spots' on abdomen constipation then diarrhoea
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reactivation of toxoplasmosis in AIDS likely leads to what radiological finding?
multiple well defined ring-enhancing lesions on MRI representing abscess formation
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bruciella is...
zoonotic gram -ve bacillus
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spirochetes cause which 3 big diseases?
lyme disease syphillis leptospirosis
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what antifungal inhibits squalene epoxidase?
terbinafine
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obligate intracellular bacteria (3) why?
Rickettsia Chlamydia Coxiella .. don't produce ATP of their own
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treatment for head lice?
pyrethroids/malathion/ivermecin lotion
nit combing
treat at home without taking child out of school
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EBV and CMV are also known as?
HHV-4 and HHV-5 respectively
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Adult meningitis bugs (3)
S pneumoniae, N meningitidis, HSV-2 (NB HSV-1 gives encephalitis)
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cat scratch disease caused by...
bartonella spp.
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Bordet-Gengou medium is used to culture...
*Bordetella pertussis* specifically
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an oocyst on acid-fast stain
cryptosporidium
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which HHV?
HHV-2
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branching filamenotous gram-positive bacteria with sulphur granules that stain dark purpule on H&E
what bug? Rx?
actinomyces
Penicillin
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gas gangene commonly caused by?
clostridium perfringes
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what cellular structure of N meningitidis is it's main virulence factor? another important virulence factor?
Pilus - allows for adherence to mucosal epithelial cells, subsequent invasion of vaculature then haematogenous spread to BBB.
IgA protease - destroys mucosal antibodies allowing colonisation
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clinical test confirming Legionella infection?
urine legionella antigen
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most common bugs for meningitis
neonatal and adult
NN - GBS then E Coli (both found in birth canal) & *Listeria monocytogenes*
adult - *Strep pneumoniae* and *N meningitidis*
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a thorn-prick/inoculation of fungus through vegitation leading to ascending lymphangitis
sporothrix schenckii
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Hib commonly causes which 4 diseases?
what is the primary virulence factor of Hib?
1. meningitis
2. pneumonia
3. epiglottitis
4. septicaemia
VF - PRP capsule allowing evasion of mucosal immunity
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A silver stain is useful to identify which microbes?
Fungi Legionella H Pylori
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'hot tub' folliculitis is caused by what bug?
pseudomonas aeruginosa
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acute epiglottitis ... what bug?
*Haemophilus influenzae B*
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alpha-haemolytic, optochin sensitive strep is...
strep pneumoniae
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other than strep, which Gram +ve bacteria is beta-haemolytic?
staphylococcus aureus
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sweet breath odour in the setting of increasing oxygen req's, sputum production and fever suggests what bug?
pseuomonas aeruginosa
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what bug is this? 3 diseases it can cause in healthy people? neutropenia?
1. vulvovaginal candidiasis
2. cuteneous candidiasis
3. oral thrush
neutropenia - disseminated disease that can affect any system (pneumonia, oesophagitis, right-sided endocardidis, abscesses, sepsis)
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what do the -azole antifunglas do?
inhibition of ergosterol synthesis, which inhibits cell wall production
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bugs responsible for bacterial pneumonia 2ary to influenza virus, in order (3)
*Strep pneumoniae*, *staph aureus* & *H influenzae*
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haemophilus is...
respiratory gram -ve bacillus
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contact with sheep/cow, pneumonia (culture -ve), retroorbital headache, fever \>10 days duration
labs: thrombocytopenia, transaminitis
progression to fatal endocarditis
disease? bug? Rx?
Q fever
*Coxiella burnetii*
doxycycline [and hydroxychloroquine until aPL antibodies \<75 GPLU]
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how does endotoxin activate macrophages? release of what? (4)
activation of TLR4 results in release of IL-1, IL-6 and TNF-alpha, NO
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who gets palivizumab prophylaxis?
how does it work and what does it protect against?
preterm infants
monoclonal Ab versus surface F protein on paramyxoviruses (childhood respiratory diseases), which usually targets these viruses to the respiratory tract
Specifically protects against RSV LRTI
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EHEC makes which toxin? mechanism of action?
EHEC - Shiga-like toxin, inhibition of 60S ribosomal subunit. Intestinal mucosal cell death, bleeding and diarrhoea.
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what is the broad budding infectious fungus?
blastomyces
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ETEC - makes what toxin? Mechanism of action?
heat-stable/heat-liable toxins.
HLT --\> activates cAMP --\> increase Cl- secretion
HST --\> activate cGMP --\> decrease NaCl/H2O resporbtion
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bird and bat droppings
Ohio and Mississippi river basins
*histoplasma capsulatum*
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what infections are caused by pseudomonas?
Hot tub foliculitis
pneumonia (CF/ventilated patients)
otitis externa (malignant)
septicaemia in neutropenia/burns
ecthyma gangrenosum
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elderly, mosquito bite in summer
meningoencephalitis, flaccid paralysis, morbilliform rash
what is the virus and what structure genome?
West Nile virus - ARBOvirus (arthopod-borne)
+ sense, ssRNA
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what Gram +ve most likely gives PSGN?
***streptococcus*** *pyogenes*
usually gives impetigo first, then PSGN
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treatment for *toxoplasma gondii*?
pyrimethamine
sulfadiazine
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what is the DNA structure of HBV and how does it replicate in the cell?
entry of virus into cell with partially dsDNA
partially dsDNA completed upon entry to host nucleus
host RNA polymerase makes mRNA, proteins are translated
RTase makes partially dsDNA from mRNA for progeny virions
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to what bug does lecithinase belong and how is it a toxin?
*Clostridium perfringes*
breaks down phosopholipid bylayer components causing cell lysis, tissue necrosis and oedema
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what is the most common bug causing infection on foreign body implants?
what is the virulence factor important in this?
*Staphylococcus epidermidis*
formation of polysaccheride biofilm
