Week 4 Part 1 Flashcards
1
Q
Who first described bacterial shapes and published micrograpia?
A
van Leeuwenhoek
2
Q
what is the cell envelope primarily composed of?
A
phospholipids
3
Q
what are the main functions of the cell envelope?
A
- transport of substances into and out of the cell
- energy production (electron transport chain)
4
Q
plasmids may carry genes for activities such as what?
A
- antibiotic resistance
- production of toxins
- synthesis of enzymes
5
Q
plasmids may be transferred from one bacterium to another and genes may be moved from plasmid to chromosome. These genes are called what?
A
transposable genetic elements or transposons
6
Q
What are the 6 classifications of bacteria?
A
- cocci
- bacilli
- coccobacilli
- spiral bacteria
- vibrios
- spirochetes
7
Q
bacteria have ___ names
A
binomial
8
Q
what is the purpose of the gram stain?
A
makes bacteria visible under a microscope because they are transparent
9
Q
what is the color of a gram positive bacteria?
A
blue/purple
10
Q
what is the colour of a gram negative bacteria?
A
red
11
Q
describe the cell wall of gram positive bacteria
A
many layers of peptidoglycan forming a thick rigid structure
12
Q
describe the cell wall of a gram-negative bacteria
A
it contains only one or very few layers of peptidoglycan
13
Q
the outer membrane of gram negative bacteria is composed of what?
A
lipoproteins, lipopolysaccharides, and phospholipids
14
Q
bacteria that have what will not stain by gram?
A
a waxy wall
15
Q
what are examples of bacteria that need to be stained by acid-fast
A
myobacteria, nocardia (cellulitis)
16
Q
What is the cell wall of bacteria stained by acid-fast composed of?
A
different lipids (mycolic acid)
17
Q
what is a capsule normally made of?
A
glycocalyx (a polysaccharide)
18
Q
what are the 5 functions of a capsule?
A
- protects from desiccation (drying out)
- promotes concentration of nutrients outside of the cell
- adherence
- protection from the immune system
- protection from toxic materials in the environment
19
Q
what are examples of microorganisms that have a capsule?
A
streptococcus pnrumoniae
nisseria meningitidies
hemophilus influenzae
20
Q
when and why do some bacteria produce endospores?
A
in the dormant stage to protect from drying out
21
Q
what are examples of spore-forming bacteria?
A
bacillus anthracis and chlostridium difficile
22
Q
endospores can be ,, and _ by location
A
central, terminal, and lateral
23
Q
what are the 3 components of the epidemiological triad?
A
the environment, agent, and reservoir
24
Q
what are the 4 types of host-pathogen interactions?
A
- symbiotic
- commensal
- mutualism
- parasitic
25
describe symbiotic
both benefit. Antagonists or synergisitic relationship
26
describe commensal
two species coexist where one benefits with no harm to the otehr
27
describe mutualism
they both benefit
28
describe parasitic
one benefits usually to the detriment of the host
29
what are colonizing flora?
usually commesals or saprobes comprised of bacteria which normally live on or in the body
30
what is an example of an opportunistic pathgeon?
candida albicans
31
what is pathogenicity?
the ability of a species to cause disease
32
what is virulence?
the ability of a strain of a species to cause disease
33
what are some factors that influence virulence?
-survival in environment
-effective transmission
-evasion of host defenses
-resistance to antimicrobial agents
-production of toxins
34
what are the two types of immunity?
innate and adaptive
35
what ecological niche has myobacterium tuberculosis developed to survive in the environment during transit?
a lipid coating to protect itself against death from drying air
36
what ecological niche has pseudomonas developed?
using minimal quantities of nutrients from water to survive for months
37
describe the process of innate immunity at the cellular level
the macrophage phagocytosis the pathogen and signals cytokines who call up neutrophils and natural killer cells to destroy the intruder
38
what appears first to the site of injury?
neutrophils and eosinophils and THEN macrophages
39
what is the goal of inflammation?
to prevent infection from setting in
to prevent the spread of infection or repair damage
to mobilize effector cells (T and B lymphocytes)
40
what are the two mechanisms of adaptive immunity?
humoral and cellular
41
describe humoral immunity
antibody-mediated immunity. With assitance from helper T cells, B cells can produce antibodies against a specific antigen neutralizing them, or causing lysis or phagocytosis
42
describe cellular immunity
occurs inside infected cells and is mediated by T lymphocytes. helpers T cells release cytokines that help activated T cells bind to the infected cells which then undergo lysis
43
what are some examples of gram positive cocci?
staphlococcus spp
streptococcus spp
enterococcus spp
44
what 2 staph strains are a part of normal skin flora?
epidermidis and warneri
45
what staph are most commonly associated with human infections?
epidermidis, haemolyticus, saprophyticus, schleiferi, and lugdunesis
46
what group of staph is not a part of normal flora?
A
47
Group A strep serotypes or genotypes have been identified based on what
M-protein serotype or M-protein gene sequence
48
What are examples of group A strep infections?
-Impetigo
-Purpeal Fever
-Scaarlet fever
-Septecemia
-pneumonia
-necrotizing fascitis
-sore throat (pharyngitis)
-erysipelas
49
Group B strep infections are linked to what?
neonatal meningitis and BSI
50
what is the primary virulence factor of streptococcus pneumoniae
an antiphagocyctic capsule
51
vaccine is available for streptococcus pneumoniae and recommended for patients with what?
splenectomy
52
What is the incubation period for streptoccocus pneomoniae?
1-3 days
53
describe some characteristics of streptococcus pneumoniae
lancet-shaped, gram-positive, cata-lase-negative, a-hemolytic diplococci
54
True or false. 21-90% of children worldwide are carriers for streptococus pneumonae
true
55
How many species of enterococcus are there?
at least 18
56
what strains account for the most human enterococcal infections?
faecalis and faecium
57
True or false. enterococcus are a part of the normal flora of the GI tract?
True
58
What type of infections can enterococcus cause?
blood, UTI, absess
59
what is the incubation period for enteroccous?
it is unkown
60
true or false. Enterococcus is highly antibiotic resistant.
True (example VRE which requires dual therapy for invasive infections)
61
What are some characteristics of bacillus anthracis?
encapsulated, spore-forming, nonhemolytic, non-motile, gram-positive, and aerobic
62
true or false. toxins are responsible for the clinical manifestations and substantial morbidity of bacillus anthracis
True
63
what are some clinical manifestations of bacillus anthracis?
hemmorage, edema, necrosis
64
how is b. anthracis spread?
by contact with or inhalation of spores
65
what are the 3 types of anthrax?
1. cutaneous
2. inhalation
3. gastrointestinal
66
what is the incubation period for cutaeous or gastrointestinal anthrax?
1 week or less
67
what is the incubation period for inhalation antheax
2 to 43 days due to spore forming characteristics
68
What are some characteristics of bacillus cereus?
gram positive, rod-shaped, facultative anaerobe, motile, B-hemolytic, spore forming
69
Where is bacillus cereus commonly found?
soil and food
70
what does bacillus cereus cause?
toxin mediated food poison
71
what is the incubation period for b. cereus?
0.5-6 hours for emetic and 6-15 hours diarrheal
72
what are some characteristics of corynebacterium diptheriae?
non-motile, non-encapsulated, non-sporulating, gram-positive, rod-shaped
73
what are the 4 biotypes of corynebacterium diptheriae?
1. mitis
2. intermedius
3. gravis
4. belfanti
74
True or false. All biotypes of c. diptheriae are toxigenic.
false. they may be toxigenic or nontoxigenic
75
what is the incubation period for c. diptheriae?
2-5 days
76
how long after recovery can b. diptheriae organisms be shed?
up to 6 weeks
77
is there a vaccine available for c. diptheriae?
Yes
78
With what microorganism does dead tissue form a pseudo-membrane in the throat or nose?
corynebacterium diptheriae
79
what are some characteristics of listeria monocytogenes?
faculatative anaerobe, non spore-forming, non branching, motile, gram-positive rod that multiplies intracellularly
80
where is listeria commonly found?
ready to eat meats, deli cuts, unpasteurized dairy, ice cream, and fresh and frozen fruits and vegetables
81
Why is listeria serious in the pregnant population?
transplacental transmission following maternal bacteremia
82
what is the incubation period for listeria in the non-pregnant population?
1-14 days
83
what is the incubation period for listeria in pregnant women?
2-4 weeks
84
True or false. Listeria is a self-limiting disease
True
85
severe listieria cases might present with what conditions?
encephalitis, meningitis, endocarditis in neonates and immunocomprimised patients
86
Neisseria meningitis is a gram ___ ___ with ___ serogroups based on ____
negative; diploccocus; 13; capsular type
87
is Neisseria meningitis aerobic or anaerboic?
it is aerobic but can survive under anaerobic conditions
88
describe the seasonality of neisseria meningitidis
seasonal character 2 to 3 weeks following onset of influenza outbreaks, with peak cases in January, February, and March
89
asymptomatic colonization of the upper respiratory tract common in older adolescents and young adults
Neisseria meningitidis
90
how does transmission of neisseria meningitidis occur?
human to human interaction
91
Is neisseria meningitidis sensitive to antibiotics?
Yes
92
Describe some characteristics of enterobacteriaeceae?
gram-negative, facultatively anaerobic, rod-shaped
93
Salmonella is part of what family?
enterobacteriaeceae
94
what diseases do enterobacteriaceae cause?
everything from UTIs to pneumoina
95
what is the most common serotype of the enterohemorrhagic serotypes for E. Coli?
E. Coli 0157:H7 (STEC)
96
what are some clinical manifestations of STEC?
diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome
97
STEC typically begins with ___ and hemorrhagic colitis starts _ days later
non bloody diarrhea, 2-3
98
what are the 5 different types of E. coli that make people sick?
* shiga toxin-producing (STEC)
* Enteropathogenic (EPEC)
* Entertoxigenic (ETEC)
* Enteroinvasive (EIEC)
* Enteroaggregative (EAEC)
99
Which type of E. coli is travellers diarrhea?
enterotoxigenic E. coli
100
Diarrhea with fever is what type of E. coli?
enteroinvasive e.coli
101
dysentery is caused with what type of E. coli?
enteroinvasive E. coli
102
what type of salmonella is the most frequently identified case of enteric disease
salmonella bongori
103
what is the reservoir for salmonella?
birds, repitiles, amphibians
104
how is salmonella transmitted?
oral fecal
105
describe some characteristics of Shigella
facultative aerobic, gram-negative bacilli in the enterobacteriaceae family
106
how many shigella species are there?
4
107
what are the 4 shigella species?
-boydii
-dysenteriae
-flexneri
-soneii
108
how is shigella transmitted?
fecal oral
109
what is the inoculum for infection for shigella?
it is as low as 10 m.o.
110
what is the incubation for shigella?
1-3 days
111
is shigella antibiotic resistant?
yes
112
shigella is viable in water up to __ days and in food up to __ days
6; 30
113
True or false. bloody diarrhea is a characteristic of shigella?
True
114
What are some characteristics of pseudomonas aeruginosa?
aerobic, gram negative, nonfermenting bacillus commonly found in the environment
115
What microorganism forms biofilms?
pseudomonas aeruginosa
116
what can o. aeruginosa colonize?
GI, GU, and sometimes respiratory tract
117
what are sources for psudomonas outbreak?
they are water loving, drains, respirators may be sources
118
what is an example of an opportunistic pathogen?
pseudomonas aeruginosa
119
which organism has a characteristic grape like fruity scent?
pseudomonas aeruginosa
120
is pseudomonas antibiotic resistant?
Yes
121
what is another water loving opportunistic pathogen?
acinetobacter baymanii stenotrophomonas maltophilia
122
which patients may become colonized for burkholderia cepacia?
cystic fibrosis
123
cystic fibrosis patients who become colonized with B. cepacia are at risk for what?
-pneumonias
-cepacia syndrome (sepsis with high mortality)
124
True or false. Burkholderia cepacia is highly antibiotic resistant
True
125
how is B. cepacia transmitted?
-contact between colonized and non-colonized patients
-outbreaks from point sources (nebulizers, respiratory therapy equipment, water sources)
126
legionella pneumophilia multiples in water what temperature?
between 24 degree celcius - 42 degrees celcius
127
what is the most common cause of respiratory disese?
legionella pneumophilia
128
what are the two types of legionella pneumophilia?
-legionnaire's disese (acute respiratory tract infections)
-pontatic disease (self-limited flu like illness)
129
what is the incubation period for legionnaire's disease?
2-10 days
130
what is the incubation period for pontiac disese?
1-2 days
131
can legionella be spread human to human?
No
132
legionella pneumoniae usually infects those with what?
respiratory omprimise or renal disease
133
outbreaks of legionella pneumoniae are linked to what?
cooling water towers, hot tubs, produce foggers
134
describe some characteristics of vibrio organisms
facultative anerobes, motile gram-negative bacilli
135
vibrio organisms are tolerant of what?
salt
136
what vibrio causes septicemia and wound infections?
V. vulnificus
137
the most common nontoxigenic vibrio species associated with diarrhea are?
choelrae and parahaemolytcus
138
what is the incubation period for vibrios?
24 hours
139
describe some characteristics of camplybacter jejuni
comma-shaped, motile, gram negative bacilli
140
what does campylobacter jejuni cause?
gastroenteritis which can be drug resistant
141
what species in the Campylobacter family most commonly are found in patients with diarrhea
jejuni and coli
142
what is the reservoir for campylobacter?
poultry, unpasteurized milk, untreated water
143
what is the incubation period for campylobacter jejuni?
2-5 days
144
which gram-negative bacilli causes duodenal ulcers?
helicobacter pylori
145
what is the source of helocobacter pylori?
soil
146
what is an anaerobe?
it grows in the absence of oxygen
147
what is an obligate anaerobe?
it can not survive in the presence of oxygen
148
what is an aertolerant anaerobe?
it can survive but grows best in the absence of oxygen
149
what is a facultative anaerobe?
it will grow equally well in the absence of presence of oxygen
150
where do we find anaerobes?
-all mucus membranes
-skin
-large numbers in the bowel
151
true or false. Anaerobes stink
true
152
why is it important to know where we find anaerobes?
because if you take a specimen through a mucus membrane, you will grow anaerobes (this is why you must aspirate or get a tissue specimen)
153
what is an example of anaerobic gram-positive bacilli?
the sporm-forming, toxin mediated Clostridium species
154
what are the 4 spore-forming clostridium species?
-clostridium tetani (tetanus)
-clostridium perfringens (gas gangrene)
-clostridium botulinum (botulism)
- c. difficile
155
describe some c. diff characteristics
-spore forming
-obligate anaerobic
-gram-positive bacillus
-some strain produce exotoxins A and B
156
some toxin producing c. diff strains lead to what?
pseudomembranous colitis
157
what is the treatment for c. diff?
vancomycin, stool transplant, metronidazole
158
what percentage of adults are colonized with c. diff?
3 to 26%
159
what is the tuberculosis incubation period?
2-10 days
160
True or false. A positive TST indicates posible infection with M. tuberculosis
True
161
How is a TST read?
Read as induration. >10mm in immunocomprimsied and >5mm is considered positive
162
what are the two TB tests?
-TST
-intreferon gamma release assay (IGRA)
163
what is latent TB defined as?
a person who has a positive TST or IGRA result but
-no physical findings of disease
-chest x-ray findings that are normal
164
Active TB presents with what?
symptoms and an abnormal chest x-ray
165
when can TB precautions be lifted?
when the person has had 2 weeks of effective therapy, is improving clinically, and has three consecutive sputum smears negative for AFB, collected 24 hours apart
