Gram negative pathogens (complete) Flashcards
1
Q
What are the Gram-negative pathogens we study
A
- Neisseria species
- Escherichia Coli
- Shigella species
- Salmonella species
- Klebsiella pneumoniae
- Yersina species
- Bordetella pertussis
- Pseudomonas aeruginosa
- Francisella tularenesis
- Legionella pneumophila
2
Q
What group is the largest group of human pathogens and why
A
Gram-negative bacteria, in part because of the Lipid A in their cell wall
3
Q
What does Lipid A trigger in humans
A
Fever, vasodilation, inflammation, shock, and disseminated intravascular coagulation (blood clots in blood vessels)
4
Q
What are the three things that any gram-negative bacteria needs to cause disease or death in humans
A
- breach the skin or mucus membranes
- grow at 37 degrees celcius
- evade the immune system
5
Q
What is the only Gram-negative Cocci that regularly causes diseases in humans
A
Neisseria
6
Q
What do Neisseria usually look like
A
gram-negative diplococci, in pairs, with flattened sides
7
Q
are neisseria aerobic or anaerobic
A
aerobic
8
Q
What are the two pathogenic types of neisseria
A
neisseria gonorrhea
neisseria meningitidis
9
Q
neisseria are pyogenic, or pyrogenic
A
pyogenic (pus creating)
10
Q
What is the isolation media used for neisseria
A
chocolate agar, + increased CO2
11
Q
What is the major virulence factor of neisseria gonorrhea
A
the attachment pili
12
Q
what is the most common reportable disease is the US
A
gonorrhea
13
Q
What happens to males with gonorrhea
A
infection of the anterior urethra = acute inflammation
pus discharge and painful urination
can cause rectal or pharyngeal infections also
14
Q
What happens to females with gonorrhea
A
infection of vaginal-cervical junction
80% of infections are asymptomatic
may cause salpingitis
may spread to lower abdomen and cause Pelvic Inflammatory Disease (PID)
15
Q
What is salpingitis
A
a gonorrhea infection of the fallopain tubes (20% sterility rate)
16
Q
What happens to children with gonorrhea
A
as they pass through the birth canal they can contrat gonococcal opthalmia neonarum (eye infection)
17
Q
What is done to prevent gonococcal opthalmia neonarum
A
antibiotic ointments placed in the eyes of newborns
18
Q
What is neisseria gonorrhea transmitted
A
sexual contact
19
Q
which age group has the highest incidence of neisseria gonorrhea
A
20-24
20
Q
How is gonorrhea diagnosed
A
by the symptoms, and observation of the organisms in the pus
21
Q
What is the treatment for gonorrhea
A
used to be penicillin, but not it has 50% resistance
now it is cephalosporin + tetracycline
22
Q
how is gonorrhea prevented
A
controlling sexual behavior
23
Q
Where can you find neisseria meningitidis
A
only in humans (normal microbiota of the upper respiratory tract)
24
Q
What is the problem with neisseria meningitidis
A
when the bacteria gets in the blood or cerebrospinal fluid it becomes life threatening meningitis
25
neisseria meningitidis is the most common cause of meningitis in individuals _____
under 20
26
How is neisseria meningitidis transmitted
| how How
respiratory droplets among people living in close contact (dorms and barracks)
27
What are the two diseases associated with neisseria meningitidis
meningococcal meningitis
| meningococcal septicemia
28
how quickly can meningococcal meningitis go from initial symptoms to death
6 hours
29
what is meningococcal septicemia
blood poisoning by neisseria meningitidis. produces blood coagulation and the formation of minute hemorrhagic lesions.
30
What are the two virulence factors of neisseria meningitidis
the capsule and the endotoxin
31
how is neisseria meningitidis transmitted
aerosol droplets, close contact facilitates transmission
| carrier rate is higher in military personnel
32
How is neisseria meningitidis diagnosed
symptoms, characteristics
33
How is neisseria meningitidis treated
i.v. penicillin or cephalosporin
34
What should high risk populations for neisseria meningitidis do
get the quadrivalent vaccine
35
What are enterobacteriaceae
a large family of gram-negative rods
36
What kinds of interaction do enterobacteriaceae have with oxygen
facultative aerobic
37
are enterobacteriaceae common commensals in humans
yes
38
what are the three types of surface antigens on enterobacteriaceae
O, K, and H
39
are enterobacteriaceae infections common nosocomial infections
yes
40
how well do disinfectants and antibiotics work against enterobacteriaceae
disinfectants easily kill them, antibiotics do not
41
What are the three types of enterobacteriaceae
1. coliforms - those that ferment glucose
2. noncoliforms - those that don't ferment glucose
3. Frank pathogens
42
What does the presence of coliforms in water indicative of
impure water, and poor sewage treatment
43
What is the most common and important of the enterobacteriaceae coliforms
Escherichia Coli (E. Coli)
44
What are the most common diseases associated with E. Coli
UTIs and Gastroenteritis
45
What is the most common cause of non-nocosomial UTIs
E. Coli
46
What are the two main virulence factors of E. Coli
pili and exotoxins
47
What are the 5 main different varieties of E.Coli
Uropathic E. Coli - more likely to produce UTI
Enterotoxogenic E. Coli - causes diarrhea
Enteropathogenic E. Coli - infant diarrhea
Enterohemorrhagic E. Coli - Hemolytic Uremic Syndrome
Enteroinvasive E. Coli - causes dysentary
48
Why is type 1 pili of E. Coli important
those E. Coli with type 1 Pili can hold on to the bladder and aren't flushed out, so they can cause a UTI. Those without it are flushed out and not pathogenic
49
what causes most E. Coli Epidemics
undercooked ground beef, unpasteurized milk or juice, or fresh vegetables
50
What is shigella
a gram-negative nonmotile bacteria that is a parasite of the human digestive system
51
what is the diseases associated with shigella, and what causes it
the disease is a bacillary dysentary called shigellosis, the diarrhea inducing enterotoxin is what causes it
52
shigella is spread by the 5 Fs, what are they
```
flies
fingers
fomites
food
feces
```
53
What is the shigella toxin similar to, and how
it is similar to the ricin toxin, it is similar because it is an AB toxin, it inactivates ribosomes, and causes apoptosis
54
What happens with shigella once it enters the cell
it is absorbed into a phagosome, which it escapes, then polymerizes actin into a tail and flies around the cell and into others
55
What does salmonella do once absorbed into marcophages
it multiplies in them and spreads
56
Where is salmonella found
in the intestines and feces of most birds, reptiles and mammals
57
What is the most common cause of salmonella infections for humans
food contaminated with animal feces
58
What are the two important pathogens of salmonella
Salmonella enterica serovar typhimurium
| Salmonella enterica serovar typhi
59
what does Salmonella enterica serovar typhimurium cause
salmonellosis
60
what does Salmonella enterica serovar typhi cause
typhoid fever
61
Where can you find Salmonella enterica serovar typhi
only in humans
62
how do you get Salmonella enterica serovar typhi
ingestion of food or water that is in from sewage contaminated with the bacteria
63
What happens with Salmonella enterica serovar typhi once you ingest it
it goes from the intestines into the blood, to the liver, spleen, bone marrow, and gall bladder, then back into the intestines and all over again. can cause peritonitis
64
Who was typhoid mary
a cook with Salmonella enterica serovar typhi, that accidentally killed many families by feeding them contaminated food
65
How is typhoid fever treated
with antimicrobial drugs
66
how is typhoid fever prevented
temporary vaccines can be given to those traveling to areas where typhoid fever is endemic
67
how does salmonella get through the intestinal walls
it causes the M-cells to ruffle so it can go through
68
What is klebsiella
an opportunist with a capsule that protects it from phagocytosis
69
what is the most common pathogenic type of klebsiella
Klebsiella pneumoniaea
70
What does Klebsiella pneumoniaea cause
pneumonia, and maybe bacteremia, meningitis, wound infections, and UTIs
71
What is Yersina
a normal pathogen of animals that can be acquired via consumption of food or water contaminated with animal feces
72
What are the three important yersina species
Yersina enterolitica
Yersina pseudotuberculosis
Yersina pestis
73
What is caused by a Yersina entericolitica infection
inflammation of the intestinal tract (similar symptoms to appendicitis)
74
What is caused by Yersina Pseudotuberculosis
less severe inflammation of the intestinal tract than Yersina entericolitica
75
What is caused by Yersina Pestis
the bubonic plague
high fever, swollen painful lymph nodes (buboes)
pneumonic plague
76
How quickly does a respiratory infection of yersina pestis kill
2-4 days from exposure to death.
77
how quickly after symptoms begin does treatment have to be started to prevent death
treatment must be started within 24 hours of symptoms onset or fatality is near 100%
78
What are the virulence factors of yersina pestis
F1 capsule - antiphagocytotic
T3SS - delivers YOPS
YOPS - inhibit cytokines, destroy cytoskeleton, trigger apoptosis
79
What is bordetella
a small aerobic nonmotile coccobacillus
80
What is the most significant bordetella
bordetella pertussis
81
what does bordetella pertussis cause
pertussis ((whooping cough))
82
Who is most commonly infected with bordetella
children
83
what are the virulence factors of B. pertussis
Adhesons
| Toxins
84
How is B. pertussis transmitted
inhaled in aerosols
85
What are the two pertussis adhesons
filamentous hemagluttinin and perussis toxin
86
What are the four B. Pertussis toxins
pertussis toxin
Adenylate cyclase toxin
dermonecrotic toxin
Tracheal cytotoxin
87
what does pertussis toxin cause
increased mucus production
88
what does adenylate cyclase toxin cause
increased mucus production and inhibition of leukocyte functions
89
what does dermonecrotic toxin cause
constriction and hemorrhage of blood vessels
90
what does tracheal cytotoxin cause
inhibits cilia movement and kills ciliated cells
91
Where can pseudonomads be found
water and plants
92
why are pseudonomads problematic in hospitals
because they can be found in numerous locations
93
what is the most common human pseudonomad pathogen
psuedomonas aeruginosa
94
Who is typically infected with pseudomonas aeruginosa
immunocompromised patients
95
What condition is often worsened by pseunomonas aeruginosa
cystic fibrosis, it increases the likelyhood of death in these patients
96
what does pseudomonas aeruginosa do to protect itself from phagocytes
forms a biofilm
97
What else is pseudomonas aeruginosa involved in
infections of severe burns
| hot tubitis
98
What are some diagnostic characteristics of pseudomonas aeruginosa
pyocyanin - a blue-green pigment with a fruity odor
| fluorescent pigment
99
how easily is pseudomonas aeruginosa treated
not easily, it is resistant to many antibacterial drugs
100
What is francisella tularensis
nonmotile strict aerobe found in animals, that causes tularemia
101
how is francisella tularensis trasmitted to humans
bite of an infected tick or deerfly, or contact with an infected animal
102
how infectious is francisella tularensis
very, less than 10 cells needed, and it can spread through unbroken skin and mucus membranes
103
Why is tularemia often misdiagnosed
its symptoms are common to other bacterial and viral diseases
104
What is different about the necessary conditions of legionella pneumophilia
it needs cysteine, iron and a lower pH (6.9) to grow
105
how do humans become infected with legionella pneumophilia
inhaling the bacteria in aerosols from various water sources
106
legionella are intracellular parasites
that is true
107
What causes legionaires disease (causes pneumonia)
legionella pneumophilia
108
how do you eliminate the legionella pneumophilia
you can't, but you can reduce their numbers to successfully control it
109
what kind of agar is legionella pneumophilia grown on
charcoal agar
110
how and where does legionalla pneumophilia multiply in humans
it multiplies in macrophages
1. it gets phagocytosed (OMP and Mip assist)
2. the phagosome is coated in ribosomes and mitochondria (don't let the phagosome fuse)
3. legionella multiplies inside the macrophage to very high numbers, then the release a pore forming toxin and lyse the cell, then spread.
