L7 Aerobic +ve pathogens Flashcards
1
Q
what are the groups of gram positive bacteria
A
firmicutes
actinobacteria
2
Q
what are firmicutes characterised by
A
low GC
3
Q
what are actinobacteria characterised by
A
high GC
4
Q
what is the ‘respiration’ of staphylococci
A
facultative anaerobe
5
Q
are staphylococci motile
A
no
6
Q
what are the diagnostic tests for staphylococci
A
catalase positive coagulase positive(s. auerus) others are negative
7
Q
what differentiates staph aureus in diagnostic tests
A
it is coagulase positive
8
Q
where are s. aureus a normal part of flora
A
skin
mucosal surfaces
9
Q
where are the most common sites for s.aureus to be
A
anterior nares, throat and groins
10
Q
how does s. aureus spread
A
direct contact or formites (survives on dry surfaces)
11
Q
what type of pathogen is s. aureus
A
opportunistic
12
Q
where is s. aureus a risk
A
presence foreign body (e.g. splinter, catheter)
surgical proceudre
13
Q
how is s. aureus diagnosed
A
selective media (e.g. salt mannitol) biochemical tests (e.g. coagulase) PCR/molecular probes
14
Q
what is antibiotic resistant s. aureus called
A
Methicillin resistant S. aureus
15
Q
what percentage of the population are carriers of s. aureus
A
20%
16
Q
what is enterocolitis
A
inflammation of the digestive tract caused by s. aureus
17
Q
what is empyema
A
collection of pus in the pleural cavity caused by s. auerus
18
Q
what is pyomyositis
A
rare bacterial infection of skeletal muscles caused by s. aureus
19
Q
what is the treatment for MRSA
A
vancomycin
20
Q
does s. aureus have a capsule
A
yes
21
Q
what is the capsule for in s. aureus
A
inhibits phagocytosis, facilitates adherence
22
Q
what is protein A for in s. auerus
A
immune evasion factors
inhibits complement/AB function, reduce opsonisation
23
Q
why does s. aureus have teichoic acids
A
bind fibronectin
24
Q
what are the enzymes that s. aureus has
A
coagulase nucleuase fibrinolysin hyaluronidase lipase
25
what are coagulase enzymes for in s. auerus
clot plasma
26
what are nucleuase enzymes for in s. auerua
hydrolyse DNA
27
what are fibrinolysin enzymes for in s. aureus
degrade fibrin clots
28
what are hyaluronidase enzymes for in s. aureus
degrade hyaluronic acid
29
what are lipase enzymes for in s. aureus
degrade lipids
30
where is s.epidermis a normal commensal
skin
gut
respiratory tract
31
what pathogen is s. epidermis
opportunistic
32
where does s. epidermis colonise
implants as a biofilm
33
why is s. epidermis hard to treat
often resistant to most anti‑staphylocccal agents: methicillin-resistant S. epidermidis (MRSE)
produce a biofilm - glycocalyx
34
what is the 'respiration' of streptococcus and enterococcus
mainly facultative anaerobes
35
what is capnophilic
some strep and entrococcus need some co2 for growth
36
are strep and entrococcus motile
no
37
what morphology are strep and enterococcus found in
pairs or chains
38
what is the catalase for strep and enterococcus
negative
39
what do strep and enterococcus ferment carbohydrates into
lactic acid
40
how many strep species are there
>100
41
how many enterococcus species are there
>50
42
what are the schemes to classify strep
serologic properties - lancefield groupings (A, B, C, F, G)
haemolytic patterns:
biochemical (physiological) properties
43
types of hemolysis
1. complete (beta [β]) haemolysis
2. incomplete (alpha [α]) haemolysis
3. no (gamma [γ]) haemolysis
44
how are beta haemolytic strep categorised
lancefield grouping (A, B, C, F, G)
45
how are alpha and gamma haemolytic strep categorised
collectively termed viridans streptococci
46
what is GAS
group A strep
47
what is s. pyogenes
GAS
48
where is s. pyogenes present
nasopharynx of healthy adults and children: strep throat
49
what caused scarlet fever
s. pyogenes
50
how does s. pyogenes spread
from person to person through respiratory droplets
51
how are s. pyogenes grouped
subdivided into Griffith types based on serology of three surface protein antigens: M, R, T
52
what is the virulent strains of s. pyogenes
with M protein
53
why is M protein virulent in s. pyogenes
inhibits phagocytosis
54
what is the treatment for s. pyogenes
penicillin and amoxicillin
| no vaccine
55
what is the presumptive identification method for s. pyogenes
PYR and bacitracin test
56
what infections does s. pyogenes cause
suppurative
| non suppurative
57
what are the suppurative infections that s. pyogenes causes
```
pharyngitis & tonsillitis
scarlet fever
necrotizing fasciitis (“flesh-eating disease”)
otitis media
pneumonia
streptococcal TSS
```
58
what are the non suppurative infections s. pyogenes causes
rheumatic fever
| acute glomerulonephritis
59
how is scarlet fever seen physically
rash and strawberry tongue
60
what are the virulence factors of s.pyogenes - structural
capsule (some strains)
M proteins
teichoic acids
61
what are capsules for in s. pyogenes
inhibits phagocytosis, facilitates adherence
62
what are M proteins for in s. pyogenes
anti-phagocytic, prevents opsonisation
63
what are teichoic acids for in s. pyogenes
bind fibronectin
64
what are s. agalactiae
group B strep
65
what is GBS
group B strep
66
where does s. agalactiae colonies
lower GI tract
| genitourinary tract
67
what is the haemolysis of s. agalactiae
beta
| 1-2%strains none
68
what does s. agalactiae cause in newborns
meningitis
pneumonia
sepsis
69
why does s. agalactiae affect newborns
absence of maternal protective AB
| low complement levels
70
what does s. agalactiae cause in adults
bacteremia, pneumonia
bone and joint infections
skin and soft tissue infections
pregnant women: urinary tract infections
71
what bacterias work together to give a bigger haemolysis
s. aureus and GBS
| s. aureus makes another protein that synergistically works with GBS = bigger clearing
72
what is the haemolysis of s. pneumoniae
alpha
| can be beta if grown anaerobically
73
what do the virulent s. pneumoniae carry
capsule
74
where does s. pneumoniae colonise
upper respiratory tract
mouth
pharynx
75
what does s. pneumoniae cause
pneumonia
meningitis
otitis media
sinusitis
76
why is s. pneumoniae difficult to isolate
fastidious
77
how is s. pneumoniae diagnosed
sensitive to optochin, ferments inulin, and lysed by bile salts
78
what is the treatment for s. pneumoniae
vaccines available: PCV and PPV in the UK
79
how many species of bacillus are there
~300
80
does bacillus species make spores
endospore forming
81
what is the 'respiration' of bacillus
aerobic or facultative anaerobe
82
what is the shape of bacillus
rod
83
are bacilli motile
some
84
which are the pathogenic bacillus
b. cereus
85
where is b. cereus present
ubiquitous - all environments
86
what pathogen is b. cereus
opportunisitic
87
what does b. cereus cause
vomiting disease – toxin in food
diarrheal disease – GI tract infection
ocular infections, complete eye loss in 48 h
intravenous catheter - sepsis
severe pneumonia (rare; after acquiring B. anthracis toxin genes)
88
how do you get infected by b.cereus
food poisoning (gastroenteritis)
89
what are the vomiting toxins of b. cereus
heat stable enterotoxin
90
what are the diarrhoea disease toxins of b. cereus
heat liable enterotoxin
91
what are the eye destruction toxins of b. cereus
necrotic toxin (heat-labile)
cerolysin (alpha haemolysin)
phospholipase C
92
what shape is b. anthracis
large vegetative cell
93
is b. anthracis motile
no
94
what is the characteristic growth of b. anthracis
medusa head colonies
95
what encodes the toxin and capsule for b.anthracis
plasmid encoded
96
what does b. anthracis cause
anthrax
97
how does b. anthracis infect
humans infected through contaminated animals/animal products (also drug abusers – heroin injection)
inoculation (95%), ingestion (very rare), inhalation
98
do b. anthracis have spores
yes
| survive for years in soil
99
what is the treatment for b. anthracis
vaccines
100
how is b. anthracis detected
direct fluorescent antibody test
101
what are the virulence factors of b. anthracis
capsule (poly D-glutamate)
lethal toxin
edema toxin
102
what is the lethal toxin of b. anthracis made of
protective antigen + lethal factor
103
what is the edema toxin of b. anthracis made of
protective antigen + edema factor
104
types of anthrax
cutaneous
gastrointestinal
inhalation
105
what does listeria monocytogenes cause
listeriosis
106
is listeria monocytogenes motile
tumbling motility at 25 degrees
107
what shape are listeria monocytogenes
short rods
108
what is the haemolytic activity of listeria monocytogenes
beta
109
how is listeria monocytogenes acquired
contaminated food: soft cheese, milk, undercooked meat, unwashed raw vegetable
110
what temp ph does listeria monocytogenes grow at
wide pH and temperature range (1 – 45 °C; fridge!)
111
where is listeria monocytogenes present
widely distributed in nature restricted to
neonatal disease
pregnant women
healthy adults
112
what is the effect of early onset neonatal disease by listeria monocytogenes
spontaneous abortion
113
how is early onset neonatal disease by listeria monocytogenes trasnmitted
via placenta in uterus
114
what is the effect of late onset neonatal disease by listeria monocytogenes
meningitis, septicaemia
115
what is the effect of listeria monocytogenes on pregnant women/immune defect patients
bacteraemia
| meningitis
116
what is the effect of listeria monocytogenes on healthy adults
mild influenza-like illness, gastrointestinal symptoms, often asymptomatic = listeriosis
117
what is the group for gram positive bacteria with high GC
actinobacteria
118
what is the shape of Corynebacterium diphtheriae
club
119
is Corynebacterium diphtheriae motile
no
120
is Corynebacterium diphtheriae catalase +/-
positive
121
what is in the cell wall of Corynebacterium diphtheriae
mycolic acid
122
what is the 'respiration' of Corynebacterium diphtheriae
facultative anaerobe
123
what are the hosts of Corynebacterium diphtheriae
only humans
124
what does Corynebacterium diphtheriae cause
diphtheria
- respiratory
- cutaneous (less servere)
125
what are the diphtheria toxins
A-B exotoxin
126
what does A-B exotoxin do
inhibit protein synthesis
127
what is the diphtheria toxin encoded by
lysogenic phage (b-phage)
128
what is the treatment for diphtheria
anti-toxin and antibiotics; prevention through vaccination (now part of 5 component vaccine) & contact tracing
129
how many species of mycobacterium are there
>100
130
are mycobacterium motile
no
131
what is the 'respiration' of mycobacterium
aerobic
132
what are the pathogenic mycobacterium
Mycobacterium tuberculosis
Mycobacterium leprae: lepra
Mycobacterium africanum
Mycobacterium bovis
133
what is different in mycobacterium
Highly complex cell wall with mycolic acid = acid fast stain
134
what is the growth of mycobacterium
slow growing
135
what does the cell wall of mycobaterium include
lipid-rich
high % mycolic acid
hydrophobic
136
what is the cell wall of mycobacterium like with disinfectants/antibiotics
resistant
137
how are acid fast organisms characterised
hydrophobic, wax-like, nearly impermeable cell walls
138
what does mycobacterium tuberculosis cause
tuberculosis
139
what is tuberculosis
infects lungs but can disseminate to other sites
140
what type of pathogen is mycobacterium tuberculosis
intracellular - replicates in unactivated alveolar macrophages
141
what is the mycobacterium tuberculosis infection like
can remain dormant and establish lifelong infection
142
why does mycobacterium tuberculosis cause disease
primarily due to host response (no myco-bacterial toxin/enzyme known to destruct tissue)
143
where is mycobacterium tuberculosis present
humans are only natural reservoir: 1/3 of world population infected
144
how is mycobacterium tuberculosis spread
inhalation of infectious aerosols
145
how is mycobacterium tuberculosis diagnosed
molecular probes, tuberculin skin test (with proteins from cell wall)
QuantiFERON-TB (blood) test: ELISA-based interferon gamma release assay
146
what is the RBC virulence factor that strep pyogenes group A has
Streptolysin S
147
examples of actinobacteria (high GC)
Corynebacterium
| Mycobacterium
