L7.2 Anaerobic +ve and Atypical organisms Flashcards
1
Q
why is a mollicute an atypical organism
A
very small
no cell wall
2
Q
why are rickettsia, coxiella and chlamydia atypical organisms
A
very small
obligate intracellular
3
Q
what bacterium are in the mollicutes
A
mycoplasma
ureaplasma
4
Q
what phylum of bacteria are mollicutes
A
tenericutes
low GC
soft skinned no cell wall
5
Q
are mollicutes sensitive to antibiotics
A
resistant to those targeting cell wall as haven’t got one
6
Q
what shape are mollicutes
A
pleomorphic
coccoid and rod
7
Q
what is important to consider for mollicutes contamination
A
very small so can pass through filters - cell culture contaminants
8
Q
what do mollicutes require
A
sterols
vitamins
nucleic acid precursors
9
Q
are mollicutes saprophytic or parasitic
A
both
10
Q
what is characteristic of mycoplasma pneumoniae
A
extracellular - smallest free living bacterium
11
Q
where does mycoplasma pneumoniae infect
A
mostly mild upper respiratory tract infections
less opften atypical pneumonia and tracheobronchitis
other manifestations are rare (cardiac, neurologic, skin)
12
Q
who does mycoplasma pneumoniae infect
A
worldwide; primarily infects school age children
13
Q
what are the virulence factors for m. pneumoniae
A
P1 adhesin protein
superantigen proteins in cell membrane
toxins
14
Q
how is mycoplasma pneumoniae spread
A
nasal secretions
15
Q
how can mycoplasma pneumoniae infect again
A
immunity not life-long- can get again as adult
16
Q
where do Mycoplasma hominis, Mycoplasma genitalium and Ureaplasma urealyticum colonise
A
genitourinary tract
17
Q
how many people carry Mycoplasma hominis
A
15%
18
Q
how many people carry Ureaplasma urealyticum
A
45-75%
19
Q
what does M. genitalium and U. urealyticum cause
A
non-gonococcal urethritis
20
Q
what does M. hominis cause
A
pelvic inflammatory disease (female upper genital tract infection) pyelonephritis (kidney inflammation)
21
Q
what group are rickettsiaceae and anaplasmataceae in
A
rickettsiales - alpha proteobacteria
22
Q
what group are coxiellaceae in
A
gamma proteobacteria
23
Q
what is the difference in the cell wall for orientia
A
no peptidoglycan
24
Q
what is the difference in the cell wall for rickettsia
A
minimal peptidoglycan
25
what do orientia and rickettsia cause
various forms of typhus and related diseases, depending on species
26
what is the reservoir for orientia and rickettsia
animals/arthopods
27
how do orientia and rickettsia invade cells
phagocytosis
escape from phagosome (phospholipase!)
Multiply in cytoplasm until cell dies (typhus group) or are constantly released (spotted fever group)
28
how if orientia and rickettsia diagnosed
microscopy
microimmunofluorescence (uses antibodies against LPS and OM proteins)
PCR-based assays, depending on species
29
what is the treatment for orientia and rickettsia
tetracycline, fluoroquinolones, chloramphenicol, depending on species
30
what does coxiella burnettii cause
causes Q fever
most are asymptomatic or mild flue-like symptoms
5% hepatitis, pneumonia, fevers
Chronic Q fever: can lead to endocarditis (significant mortality; mostly predisposed patients, e.g. immuno-suppressed)
31
what are the different coxiella burnettii variants
small cell variants (stress resistant)
| large cell variants (metabolically active)
32
how is coxiella burnettii diagnosed
serological methods (immunofluorescence antibody and ELISA)
33
what type of pathogen is coxiella burnettii
intracellular
34
what are the reservoirs for coxiella burnetti
arthropods
birds
mammals: farm animals and pets
35
how is coxiella burnetti spread
resistant form can survive for years in soil, milk, faeces
| infection via inhalation of contaminated material
36
what is an infectious dose of coxiella burnetti
≤10 bacteria
37
how is coxiella burnetti diagnosed
serological methods immunofluorescence antibody and ELISA
38
what is the treatment for coxiella burnetti
doxycyline; vaccines for humans and animals available
39
what is chlamydiaceae
obligate intracellular parasite
40
how do chlamydiaceae get energy
believed to use host ATP
41
what size are chlamydiaceae and why is this important
small can pass through 0.45uM filters
42
what are the 2 forms of chlamydiaceae in the lifecycle
elementary bodies
| reticulate bodies
43
what is the chlamydiaceae lifecycle
elementary bodies invade in vacuole/phagosome, multiply in there convert to reticulate bodies
all in RB state = inclusion bodies (as vacuoles so big)
convert back to EB
cell lyse infect
cycle start again
44
what is the biovars of chlamydia trachomatis
```
trachoma (and urogenital infections)
lymphogranuloma venereum (LVG)
```
45
what infection does chlamydia trachomatis cause
trachoma: infection of the eye (conjunctiva)
| urogenital infections
46
what is the chlamydia trachomatis trachoma infection cause
scar inner surface of eye lids = eyelids turn inwards = erosion/ulceration of cornea = blindness
47
what is the chlamydia trachomatis urogenital infection cause in men
urethritis, epididymitis, infertility
48
how is chlamydia trachomatis transmitted
sexual transmission
49
what are the symptoms of chlamydia trachomatis
mainly asymptomatic
80% women
25% men
50
what is the chlamydia trachomatis disease spread in body like
progressive - genital ulcer may lead to, swelling of lymph nodes which may rupture, forming fistulas
51
what is the chlamydia trachomatis, chlamydia pneumoniae and chlamydia psittaci diagnosis
culture (requires viable cells)
serology, now routinely nucleic acid amplification tests (NAATs)
glycogen accumulation in inclusions of C. trachomatis
52
what does chlamydia pneumoniae cause
community acquired pneumonia
53
who does chlamydia pneumoniae infect
may be subclinical but more severe in elderly and asthmatics
| 60-80% of people worldwide become infected, but uncommon in childhood
54
what does chlamydia psittaci cause
ornithosis – from birds
flu-like symptoms
more severe systemic infection
55
what is the treatment for chlamydia trachomatis, chlamydia pneumoniae and chlamydia psittaci
doxycycline
| macrolides
56
are clostridium spore forming
yes
57
what metabolism do mollicutes have
saccharolytic or proteolytic
58
what are the clinical manifestations of clostridium
gas gangrene
food poisoning
tetanus
antibiotic associated diarrhoea
59
where is clostridium perfringens a commensal
human and animal gut
60
what is the shape of clostridium perfringens
rod
61
what is the growth of clostridium perfringens like
rapid- fastest growing organism
62
what does clostridium perfringens make
toxins
| haemolytic enzymes
63
what are the lethal toxins of clostridium perfringens
alpha
beta
epsilon
iota toxin
64
what is the the effect of clostridium perfringens type A
causes most human infections
| largest amount of alpha toxin
65
effect of clostridium perfringens alpha toxin
lecithinase (phospholipase C), lyses many cell types - causes massive haemolysis, tissue destruction etc.
66
what causes clostridium perfringens double zone haemloysis
alpha and theta toxins
67
where does clostridium perfringens infect
soft tissue
68
what is cellulitis
localised gas formation in soft tissue
69
what is suppurative myositis
pus in muscle planes
70
what is myonecrosis
rapid muscle tissue destruction, gas gangrene
71
how can you become infected by clostridium perfringens
food poisoning
| meat products with high spore (type A) numbers - survive heating and germinate if food not cooled
72
what does clostridium perfringens type C cause
clostridial necrotizing enteritis
| tissue destruction in jejunum
73
what is the treatment for myositis and myonecrosis
must be initiated immediately
| surgical removal of tissue and high dose penicillin
74
how is myositis and myonecrosis diagnosed
microscopy/culture (rapid growth)
75
what is the metabolism of clostridium tetani
proteolytic
76
what is clostridium tetani sensitive to
oxygen
77
what are the spores of clostridium tetani like
highly heat resistant
| ubiquitous in soil, manure
78
what toxin does clostridium tetani have
tetanospasmin - heat labile neurotoxin
79
what is the lethal dose of clostridium tetani
2.5ng/kg
80
what does the clostridium tetani tetanospasmin do
blocks neurotransmitter release of inhibitory synapses = spastic paralysis
death by asphyxia/sudden cardiac arrest
81
what is the treatment for clostridium tetani
tetanus immunoglobulin, antibiotics (penicillin)
| potent vaccine exists
82
where is clostridium tetani
ubiquitous
83
what does clostridium tetani contaminate
water food
84
what are the clostridium tetani toxins
7 main toxin types A-G
85
which clostridium tetani toxins are associated with human disease
A, B, E, F
86
how are clostridium tetani protected in digestive tract
complexed with non toxic proteins
87
effect of clostridium tetani toxin
inactivates proteins needed for acetylcholine release = no n=muscle excitation = flaccid paralysis = respiratory failure
88
what are the types of clostridium tetani infection
foodborne botulism
infant botulism
wound botulsim
89
what is infant botulism from
spores in honey, dust
90
what is the treatment for clostridium tetani
removed undigested food, give antitoxin and intensive therapy
91
what does clostridium difficle cause
antibiotic associated diarrhoea
92
how does clostridium difficle infect
spores spread infection
93
where is clostridium difficle a normal part of flora
gut of healthy individuals
2/3 babies
3% young adults
94
what disrupts the clostridium difficle to cause infection
heavy colonisation of gut following disruption of microflora:
antibiotics
chemotherapy
colonic obstruction
95
what toxins does clostridium difficle make
toxin A - enterotoxin
| toxin B - sytotoxin
96
what is the effect of the clostridium difficle toxins
mucosal inflammation
apoptosis
diarrhoea
97
what is different about the clostridium difficle toxins
synergistic, but A or B-negative isolates both appear to be able to cause disease
98
what are the clostridium difficle diagnostics
immunoassay for toxin in stool/ nucleic acid amplification tests (NAATs)
99
what is the treatment for clostridium difficle
```
discontinue antibiotics (mild cases)
metronidazole or vancomycin
faecal transplants are an option! microflora from healthy = injected into gut
```
100
what makes an organism atypical
size
cell wall
life cycle
101
which group is
| clostridium
low GC
| firmicutes
102
what is the 'respiration' of clostridium
strictly anaerobic - oxygen tolerance varies
103
anaerobic cocci examples
Peptostreptococcus
104
how are chlamydia trachomatis biovars grouped
subdivided in serovars (based on Major Outer Membrane proteins), associated with specific diseases
105
what are bacterial stain are rickettsia, coxiella and chlamydia
negative
106
what is the chlamydia trachomatis urogenital infection cause in women
women: urethritis, cervicitis, pelvic inflammatory disease, infertility or ectopic pregnancy
107
what is the chlamydia trachomatis urogenital infection cause in babies
transmission to baby at birth: infant pneumonia, conjunctivitis, middle ear infection
