Gram Negative Rods (Exam 1) Flashcards
(151 cards)
1
Q
Where are enterobacteriaceae found
A
ubiquitous: soil, water, vegetation, intestinal tract of humans and animals
2
Q
What are the air requirements of enterics
A
facultative anaerobes: can survive with or without O2
3
Q
List the gram stain results for enterobacteria
A
Gram negative
rods
4
Q
What is the oxidase result of enerobacteriaea
A
Negative
5
Q
What is the catalase of enterics
A
positive
6
Q
Do enterobacteriae ferment glucose
A
yes
7
Q
What type of agar is used to grow enterics
A
MacConkey agar
8
Q
What type of transmission is shown by enterics
A
human to human
animal to human
9
Q
What are the common virulence factors of enterics
A
capsule
Flagella
Endotoxin
10
Q
What are the antigens of the capsule for enterics
A
K antigen
Vi antigen in salmonella
11
Q
What are the antigens of the flagella
A
H antigen
12
Q
What type of secretion system do enterobacteria use
A
Type III
13
Q
How are bacteria typed
A
H antigen
14
Q
How are endotoxins typed
A
O antigen
15
Q
Where is LPS contained gram negatives
A
outer membrane
16
Q
What is MacConkey agar selective for
A
gram-negative rods
17
Q
What is MacConkey agar differential for
A
lactose fermenters
18
Q
How does MacConkey show when it differentiates
A
purple growing colonies: lactose +
beige colonies: lactose -
19
Q
What is EMB agar selective for
A
gram-negative rods; lactose fermenters
20
Q
How will EMB colony growth appear
A
dark colonies
21
Q
How will E. coli appear on EMB
A
metallic green
22
Q
What specific organisms grow on MacConkey
A
E. coli Salmonella Shigella Yersinia Klebsiella Proteus
23
Q
What specific organisms are lactose +
A
E. coli and Klebsiella
24
Q
What specific organisms are lactose -
A
Salmonella, shigella, Yersinia, Proteus
25
What organism can be used as an indicator of fecal contamination of water supplies
E. coli
26
What enteric is associated with traveler's diarrhea
ETEC
27
What does ETEC stand for
Enterotoxin E. coli
28
What are the two toxins produced by ETEC
LT1
| STa
29
What is LT1
heat labile enterotoxin
30
What is STa
heat stabile enterotoxin
31
What is the mechanism of LT1
increases cAMP
32
What is the mechanism of STa
increases cGMP
33
How ETEC transmitted
consumption of fecal contaminated food/water
34
What is the incubation period for ETEC
24-72 hours
35
What is the duration of ETEC
3-5 days
36
What are the symptoms of ETEC
explosive watery diarrhea
abdominal cramps
Fever +/-
nausea/vomiting
37
How does EIEC cause illness
invaded GI epithelium
38
Does EIEC use an enterotoxin
no
39
What is the incubation period for EIEC
10-18 hours
40
What is the durration of EIEC
3-5 days
41
What are the symptoms of EIEC
watery diarrhea
fever
abdominal cramps
bloody diarrhea
42
What is unique to the diarrhea of EIEC
starts watery diarrhea then turns to bloody diarrhea
43
What population is most effected by EPEC
Infants
| those in developing countries
44
How are infants most susceptible during EPEC
dehydration; can be fatal
45
What does EPEC stand for
enteropathogenic e. coli
46
How does EPEC cause disease
attachment using pili, destruction of microvilli, cell death
47
What feature does EPEC cause with disease
lesions in the GI tract
48
What are the symptoms of EPEC
watery diarrhea, fever, vomiting
49
What population will be affected by enteroaggregative E. coli
infants and travelers
50
What are the symptoms of EAggEC
persisten watery diarrhea for >14 days
51
What is unique about the diarrhea of EAggEC
persisten for > 14 days
52
How does EAggEC cause disease
cells for aggregates that secrete mucus and form a biofilm
enterotoxins can increase in fluids leading to watery diarrhea
53
What toxins are released by EAggEC
EAST and PET toxins
54
What do EAST and PET toxins lead to
increased fluid secretion and watery diarrhea
55
What type of E. coli will produce a Shiga-like toxin
STEC
| EHEC
56
What does EHEC stand for
enterohemorrhagic
57
What is the serotype of EHEC
O157:H7
58
The O part of a serotype is what
O antigen
59
The H part of a serotype is what
flagellar antigen
60
Where is EHEC normally found
normally in GI tract of cattle, goats, sheep
61
How is EHEC spread
fecal-oral (children at petting zoos)
62
What is the infective dose of EHEC
10-100 organisms
63
What type of toxin is produced by EHEC
shiga-like toxins
64
Where are the genes for shiga-like toxins found
phage
65
What is the mode of action of the toxin produced by EHEC
binds to 28SrRNA and disrupts protein synthesis
66
Where are the receptors for shiga toxin found
intestinal cells and kidney cells
67
How might EHEC affect the kidneys
toxin spread throughout the blood stream and binds to the kidney, the bacteria stay in the gut
68
What are the incubation period of EHEC
3-4 days
69
How long does EHEC last
3-7 days
70
What are the symptoms of EHEC
watery diarrhea progresses to gross bloody diarrhea
severe stomach cramps
low grade fever
vomiting
71
What is unique about the diarrhea of EHEC
starts as watery diarrhea but becomes grossly bloody
72
What are the two syndromes associated with EHEC
Hemorrhagic colitis
| hemolytic uremic syndrome
73
What is hemorrhagic colitis
bloody diarrhea
74
How will hemolytic uremic syndrome associated with EHEC present
hemolytic anemia
renal failure
thrombocytopenia
75
Who is most at risk for developing HUS
children and elderly
76
What percent of O157:H7 cases progress to HUS
5-10%
77
What is the treatment for hemolytic uremic syndrome associated with EHEC
fluids, supportive care, dialysis
78
What antibiotics should be used in HUS
none, it will exacerbate the disease
79
What agar can be used to diagnoses EHEC
SMAC
80
What is SMAC
sorbitol MacConkey agar
81
95% of E. coli cultured on SMAC are what
lactose +
| sorbitol +
82
O157:H7 cultured on SMAC are what
lactose +
| sorbitol -
83
What are the laboratory diagnostic methods for EHEC
serotyping using O157 and H7 antiserums
direct detection of shiga-like toxin (verotoxin)
direct PCR to detect presence of SLT genes
84
What is the leading cause of UTI
E. coli, endogenous infection
85
How does E. coli cause UTIs
uses pili to ascend into bladder
86
What is one of the major causes of neonatal meningitis
E. coli
87
How does E. coli lead to septicemia
starts in GI tract or urinary tract and spreads
88
What are the two species of Salmonella
S. enterica
| S bongori
89
What will be the lactose fermentation results of salmonella
Lactose neg
90
What is the H2S results of salmonella
H2S positive
91
What are the 2 common diseases caused by Salmonella enterica
Typhoid fever
| Enteric infections
92
What strain of Salmonella enterica causes typhoid fever
S. typhi
93
What strain of Salmonella enterica causes tyenteric infections with diarrhea
S enteritidis
94
What animals/reservoir are salmonella enterica associated with
humans and warm blood animals
95
What animals/reservoir is salmonella bongori associated with
cold-blooded animals
96
How is salmonella typhi transmitted
fecal oral route
97
Where does ingested salmonella typhi spread inside the body
small intestine to macrophages, lymphoid tissue, liver, and gall bladder
98
How can the gall bladder play a role in salmonella typhi carriers
bacteria grow in gall bladder and reach instestine thorugh bile duct
99
How long can someone shed salmonella in their feces
1 year
100
What are the symptoms of typhoid fever
```
fever
headache
abdominal pain
constipation
anorexia
malais
```
101
What is found in 25% of the typhoid fever cases
rose spots (rash) on abdomen
102
What symptoms are unique to typhoid fever
constipation
| rose spots on abdomen
103
What population is predisposed to salmonella infections
Sickle cell anemia
104
What can salmonella cause in sickle cell patients
osteomyelitis
105
What is salmonellosis causes by
S. enteridis
106
What is S. enteridis
non-typhi serotype of salmonella
107
What is the transmission of salmonellosis
fecal oral
108
What is the incubation for salmonellosis
6-48 hours
109
What are the symptoms of salmonellosis
diarrhea, nausea, vomiting, fever, abdominal cramps
110
What does a salmonella infection rely on
ability to attach and invade columnar epithelial cells and M cells
111
Where does salmonella infection divide in epithelial or M cells
phagocytic vesicles
112
What occurs after duplicating in macrophages
it kills macrophages and spreads to nearby cells
113
What are the four shigella species that are human pathogens
Shigella dysenteriae
Shigella boydii
Shigella flexneri
Shigella sonnei
114
Which shigella spp is common in the US
shigella sonnei
115
Which shigella spp is most severe disease
Shigella dysenteriae
116
What is the reservoir for shigella
humans only, no animals
117
What are the lactose of Shigella
nonfermenters
118
What is the H2S of Shigella
negative
119
What is another name for shigellosis
bacillary dysentery
120
How is shigella transmitted
fecal oral route
121
What is the infection dose for shigella
low; 10 organisms
122
What population is most at risk for contracting shigella
children, daycare centers, schools
123
What is the incubation for shigella
1-4 days
124
What is the duration of shigella
2-3 days
125
What are the symptoms of shigella
watery diarrhea
abdominal cramps
fever
bloody diarrhea with mucus
126
What is the treatment for shigella
supportive therapy; prevent dehydration
127
When will antibiotics be used in shigella infections
immunocompromised individuals
128
what does shigella use to propel from cell to cell
actin
129
What are the virulence factors of shigella
invasion proteins
130
What are the invasion proteins of shigella
IpaA, IpaB, IpaC, IpaD
131
Where are invasion proteins of shigella located
large plasmid
132
How are shigella invasion proteins passed on
secreted by type III secretion system
133
What is the toxin secreted by shigella
Shiga toxin
134
What is the mode of action for the Shiga toxin
cleaves 28SrRNA to inhibit protein synthesis
135
What is the lactose result of Klebsiella
fermenter
136
What is the Indole of Klebsiella result
negative
137
Which bacterium is indole positive
e. coli
138
What organisms is associated with a currant jelly sputum
Klebsiella pneumoniae
139
How will klebsiella pneumoniae present
thick bloody sputum
140
What are the risk factors for getting klebsiella pneumoniae
elderly males
| immunocompromised
141
What disease is caused by klebsiella granumoatous
granuloma inguinale
142
How will granuloma inguinale present
painless ulcer on genitalia
143
How is granuloma inguinal transmitted
sexual contact
144
What disease is associated with proteius
UTI
145
What are the two proteus strains
proteus mirabilis
| proteus vulgaris
146
What type of organism will display swarming motility
proteus
147
What is the main virulence factor of proteus
urease
148
What does urease do
convert urea into ammonia and CO2
149
What does urease end up causes
increase in urine pH
150
What does an increase in urine pH cause
formation of kidney stone
151
What type of calculus is formed by proteus
staghorn calculi
