MicroB Flashcards
1
Q
what bacterials grow as diplococci?
A
- strep pneumoniae (gram pos cocci)
- Neisseria spp. (gram neg cocci)
2
Q
out of all the streps, which is the one that is not part of normal flora
A
strep pneumo (group A)
3
Q
out of all the staphs, which is the coagulase positive one?
A
staph aureus - it is the only coagulase positive staph
4
Q
are all the staphs part of normal flora?
A
yes! staph aureus found in anterior nares of 30% of people; staph saprophytic found part of vagina
5
Q
what is a group A beta haemolytic gram pos cocci?
A
strep pyogenes
6
Q
what type of haemolytic bacteria is strep pneumonia?
A
alpha haemolytic
7
Q
what is the test for alpha haemolytic bacteria?
A
green tinge on blood agar
8
Q
what is the virulence for strep pneumo?
A
anti-phagocytic capsule with pneumolysin
9
Q
what can strep pneumo cause?
A
Young: otitis media and URTI Enter: endocarditis P: pneumonia M: meningitis S: septicemia
10
Q
how to test for strep pneumo?
A
culture, gram stain, urine antigen test
11
Q
how to treat strep pneumo?
A
benzylpenicillin or ceftriaxone if meningitis
12
Q
is there a vaccine for strep pneumo?
A
yes - the pneumococcal vaccine which is a conjugated vaccine (compulsory for kids in sg)
13
Q
what can strep viridans cause?
A
subacute endocarditis secondary to septicemia
dental caries
14
Q
what type of haemolytic bacteria is strep viridans?
A
alpha haemolytic (like strep pneumo)
it is a group A alpha haemolytic cocci
15
Q
what type of hemolytic bacteria is strep pyogenes?
A
beta haemolytic
it is the only group A beta haemolytic bacteria
16
Q
what does it mean to be beta haemolytic?
A
leaves a yellow tinge after breaking down the RBC on blood agar
VS alpha haemolytic which leaves a green stain
17
Q
what is the virulence of strep pyogenes?
A
streptolysin O and M protein
18
Q
what can strep pyogenes cause?
A
P: pharyngitis with sequelae of acute rheumatic fever
S: skin and soft tissue infections (e.g. scalded skin syndrome, erysipelas, bullies impetigo)
S: Scarlett fever
19
Q
how to treat strep pyogenes?
A
benzylpenicillin
20
Q
what is an example of group B strep?
A
strep agalactiae
21
Q
what type of haemolytic bacteria is strep agalactiae?
A
beta haemolytic
22
Q
what is special about strep agalactiae?
A
there is vaginal carriage in 30% of women, 30% of the time
23
Q
why is the 30%/30% thing special about strep agalactiae?
A
it means it is not persistent and can be cleared by antibiotics
24
Q
what is the treatment of strep agalactiae?
A
benzylpenicillin
25
what is a group D strep?
enterococcus spp.
26
is enterococcus part of the normal flora?
yes, its part of the GIT
27
what are the presentations of enterococcus?
E: endocarditis
N: nosocomial infections
U: UTI
28
how to treat enterococcus? (note that its a special gram pos cocci)
any beta lactam that is not cephalosporin
or vancomycin
29
how does staph aureus grow?
yellow clusters on blood agar
30
what is the virulence of staph aureus?
- alpha toxin
- toxic shock syndrome -1 toxin
- enterotoxin
- epidermolytic toxins
31
what does staph aureus cause?
mnemonic: it's dangerous so must SET BP Fast
S: skin and soft tissue infections
E: endocarditis
T: toxic shock syndrome
B: bone infections
P: pneumonia secondary to influenza
Fast: food poisoning
32
how to treat staph aureus?
cloxacillin or 5th gen cephalosporin (ceftaroline)
vancomycin for MRSA
33
what type of coagulase bacteria is staph saprophyticus?
coagulase negative
34
what do coagulase negative bacteria usually cause?
usually the ones contaminating blood cultures, prosthetics and line infections
35
what does staph sapro cause?
UTI in young, sexually active women
36
what type of bacteria is moraxella catarrhalis?
gram neg cocci
37
what does moraxella catarrhalis cause?
opportunistic chest infections like bronchopneumonia
38
what is special about the way Neisseria grows?
grows as diplococci, just like strep pneumo
39
on which medium does Neisseria grow on?
need charcoal medium for transport and to be grown in a Thayer-martin medium with rich CO2
40
what does Neisseria gonorrhoea cause?
males: acute urethritis
females: asymptomatic carriage or PID
neonates: ophthalmia neonatorum
blood: disseminated gonorrhea
41
how to treat Neisseria gonorrhoea
ceftriaxone
| azithromycin if resistant
42
do we have prophylactic treatment for Neisseria gonorrhoea and if so, what is it?
silver nitrate eyedrops for neonates
43
what is special about the virulence of Neisseria meningitidis?
it was 4 subtypes; type A, C, Y and W135
44
what does Neisseria meningitidis present as?
meningitis
meningococcemia
unique: waterhouse-friderichsen syndrome (adrenal gland failure)
45
what are the general signs of meningitis?
fever, neck stiffness, headache, non-specific macular rash
46
what are the signs of meningicoccemia?
non-blanching rash which results in a positive tumbler test
47
what does a non-blanching rash mean?
it means there is inflammation that makes the blood vessels so leaky, that the blood has entered the epidermal layers
48
how to treat Neisseria meningitidis
ceftriaxone (clears throat carriage)
| benzylpenicillin (does not clear throat carriage)
49
is there a vaccine for n. meningitidis?
yes, the meningococcal vaccine that is conjugated
compulsory for kids in sg
50
list the important gram positive rods (aerobic and anaerobic)
```
aerobic:
listeria monocytogenes
corynebacterium diphtheria
bacillus cereus
bacillus anthracis
```
```
anaerobic:
clostridium tetani
clostridium botulinum
clostridium difficile
clostridium perfringens
```
51
list the important gram negative rods (4 main types)
```
enterobacteriaceae:
E. coli
klebsiella
proteus spp
shigella dysenteriae
salmonella type
salmonella enteritidis
```
pseudomonads:
burkholderia pseudomallei
pseudomonas aeruginosa
vibrio:
vibrio cholerase
vibrio vulnificus
fastidious rods:
legionella pneumophila
haemophilus influenzae
52
what does listeria monocytogenes cause?
neonatal infections
| meningitis in immunocompromised
53
how to treat listeria monocytogenes?
ampicillin
| NOTE: resistant to all cephalosporins like enterococcus
54
what does corynebacterium diphtheria grow on?
tinsdale medium and looks like Chinese characters
55
what is the virulence of corynebacterium diphtheria?
exotoxin - diphtheria toxin
56
what does corynebacterium diphtheria cause?
URTI
bull neck appearance
myocarditis (the cause of death)
57
is there a vaccine for corynebacterium diphtheria?
yes there is and its compulsory for children (but you inject the bacteria without the toxin)
58
what is special about the treatment about corynebacterium diphtheria?
use an anti-serum and not some antibiotic
59
what does bacillus cereus cause?
food poisoning that is self-limiting
60
what does bacillus anthracis cause?
causes anthrax which results in black ulcers all over
61
how to treat bacillus anthracis?
benzylpenicillin
| ciprofloxacin
62
what is the virulence of clostridium tetani?
tetanoplasmin toxin - blocks the inhibitory signals of LMN
63
what does clostridium tetani cause?
spastic paralysis
64
how to treat clostridium tetani?
human tetanus immunoglobulin
65
what is the virulence of clostridium botulinum?
preformed botulinum toxin that blocks the NMJ junction
66
what does clostridium botulinum cause?
flaccid paralysis
67
how to treat clostridium botulinum?
antiserum
68
what is the virulence of clostridium difficile?
alpha toxin
69
what does clostridium difficile cause?
c. diff associated colitis
70
how to treat clostridium difficile?
metronidazole
| oral vancomycin
71
what is the virulence of clostridium perfringens?
lithicinase toxin
72
what does clostridium perfringens cause?
gas gangrene
73
how to treat clostridium perfringens?
penicillin
74
what is special about all the clostridiums?
they all have toxins as virulence and the first two have special treatments
75
what are the lactose fermenters of the enterobacteriaceae group?
E. coli and klebsiella (the only 2)
76
what are the different types of e.coli?
ETEC: enterotoxigenic
EPEC: enteropathogenic
EHEC: enterohemorrhagic (O157) is most common
VTEC: shigatoxin-producing
UPEC: uropathogenic
77
how to treat e.coli?
ceftriaxone, cipro, cotrimox, nitrofurantoin
78
what does klebsiella spp. cause?
UTI, liver abscess, pneumonia (caused by klebsiella pneumoniae)
79
what does proteus spp cause?
UTI
80
what does shigella dysenteriae cause?
dysentry
81
what does salmonella typhi cause
typhoid fever (this differs from typhus! which is caused of rickettsia typhi)
82
what does salmonella enteritidis cause
common bacterial cause of gastroenteritis
83
what is special about the way pseudomonas aeruginosa grows?
it grows green on blood agar
84
what does pseudomonas aeruginosa cause?
contact lens keratitis
| pneumonia or other nosocomial infections
85
how to treat pseudomonas aeruginosa?
like e.coli, it is very extensive
common treatments: ceftriaxone and cipro
86
what is special about the way burkholderia pseudomallei grows?
grows as wrinkled colonies
87
what does burkholderia pseudomallei cause?
melioidosis: fever, pneumonia, liver abscess
88
how to treat burkholderia pseudomallei?
D: doxycycline
C: coamox
C: cotrimox
C: chloramphenicol
89
what is special about the way vibrio cholerase grows?
grows in yellow colonies
90
what is the virulence of vibrio cholerase?
cholerase toxin
91
what does vibrio cholerase cause?
cholera
| the O1 type causes outbreaks
92
how to treat vibrio cholerase?
cipro and rehydration
93
what does vibrio vulnificus cause?
self-limiting watery diarrhea
94
what does legionella pneumophila cause?
```
pontiac fever
legionnaires disease (non-productive pneumonia)
```
95
how to diagnose legionella pneumophila?
since its a non-productive cough, can use a bronchoalveolar lavage to get sputum samples
can also get urine antigen test
96
how to treat how to diagnose legionella pneumophila?
IV erythromycin
| rmb leeeee-gionella, so eeeeee-rythromycin
97
what does h. influenzae grow on?
chocolate agar with X and Y factors
98
what is the virulence of h. influenzae
like strep pneumo, its capsule is the virulence factor
99
what does h. influenzae cause
encapsulated and non-encapsulated diseases
encapsulated: meningitis, pneumonia post influenza
non-encapsulated: URTI
100
how to treat h. influenzae?
ceftriaxone
101
what are the important mycoplasma/chlamydia bacteria?
- mycoplasma pneumoniae
- chlamydia psittaci
- chlamydia trachomatis
- chlamydia pneumoniae
102
what does m. pneumo cause?
"walking pneumonia" in adults = essentially atypical pneumonia
paroxysmal cough in children
103
how to treat m. pneumo?
any protein synthesis inhibitor (TAG/MCL)
104
what does c. psittaci cause?
atypical pneumonia
105
what does c. trachomatis cause?
it essentially is the STD, but different variants present differently
type A-B: trachoma (eye blindness)
type D-K: inflammatory diseases such as urethritis
type L1-L3: genital warts
106
what does c. pneumoniae cause?
atypical pneumonia
107
what are the important intracellular obligate parasites?
just rickettsia, so there's:
- rickettsia typhi
- rickettsia rickettsii
- rickettsia prowazeki
108
what does rickettsia typhi cause?
typhus (different from typhoid fever caused by salmonella typhi)
109
what does rickettsia prowazeki cause?
typhus too (abdominal pain, fever, headache, general malaise)
110
what does rickettsia rickettsii cause?
Rocky Mountain fever + centripetal rash
111
what are the important spiral bacteria?
- treponema pallidum
- helicobacter pylori
- campylobacter jejuni
112
what does treponema pallidum cause? (consider its various stages - primary, secondary, late stage, latent, neonatal)
essentially syphilis
primary syphilis: chancres and enlarged lymph nodes
secondary syphilis: mucous tracks, acute meningitis, rash on palms and soles
late stage: neurosyphilis and gummatous syphilis
latent: asymptomatic with some flares
neonatal: hutchinson's triad (eye blindness, deafness, teeth malformation)
113
how to diagnose treponema pallidum?
- dark illumination
- non-treponema antibody test (tp hemagglutinin test + tp particle agglutinin test)
- treponemal antibody test (VDRL + RPR)
114
can spiral bacteria be gram stained?
no!
115
what does h. pylori cause?
acute and chronic gastritis
PUD
increased risk for gastroadenocarcinoma
116
how to diagnose h. pylori?
fecal antigen test and urease breath test
117
how to treat h. pylori?
O: omeprazole (antacid)
A: amoxicillin
C: clarithromycin
118
what does c. jejuni cause?
gastroenteritis
119
how to treat c. jejuni?
erythromycin
| ciprofloxacin
120
how to treat treponema pallidum?
penicillin (surprisingly easy)
121
what does primary m. tb cause?
AFB have cord factor --> are phagocytosed but survive in macrophages --> accumulation of macrophages and formation of granulomas called goon's focus --> need a while for T cells to secrete TB-specific IFN-y to increase microbicidal effect of macrophages to attack these AFB-filled macrophages
122
what does secondary m. tb cause?
if there is a reinfection or reactivation of latent tb, there will be formation of caseous necrosis with cavitating granulomas
123
what does miliary tb cause?
hematogenous spread to other organs to cause caseous necrosis
124
how to diagnose tb?
- chest xray
- AFB test with ziehl-neelson stain
- Mantoux test for secondary TB (but note BCG vaccine will also have positive reaction)
125
how to treat TB?
```
R: rifampicin
I: isoniazid (must give with pyridoxine)
P: pyrazinamide
E: ethambutol
[2 months RIPE + 4 months RI]
```
if secondary tb, just give isoniazid for 6 months daily
126
what does m. leprae cause?
tuberculoid leprosy: Th1 cell response
lepromatous leprosy: Th2 cell response
127
how to treat m. leprae?
6 months of rifampicin with dapsone
