6. Enterobacteroides Flashcards
1
Q
Lactose fermenters (6)
A
Citrobacter
Cronobacter sakazakii
Enterobacter
E. coli
Klebsiella
Pantoea
Serratia
2
Q
The only ox = GNR
A
Plesiomonas shigelloides
3
Q
LLFs
A
Citrobacter koseri
Pantoea agglomerans
Serratia marcescens
4
Q
Cfre on HE
A
yellow
black centers
5
Q
E. coli on HE
A
bright yellow
salmon orange
6
Q
Proteus on HE
A
clear
blue-green
black centers
7
Q
Salmonella on HE
A
blue-green
black centers
8
Q
Shigella on HE
A
clear, blue-green
9
Q
Yersinia on HE
A
yellow
salmon orange
10
Q
Cfre on XLD
A
yellow
colorless
black centers
11
Q
most LFs on XLD
A
yellow
12
Q
Mmor on XLD
A
clear
13
Q
Proteus on XLD
A
yellow
colorless
black centers
14
Q
Providencia on XLD
A
clear
15
Q
Salmonella on XLD
A
black
red rimmed
16
Q
Serratia on XLD
A
yellow
17
Q
Shigella on XLD
A
colorless/red
18
Q
Yersinia on XLD
A
yellow
19
Q
NLFs that give an A/A TSI reaction
A
Pvul
Yersinia
20
Q
The only H2S + LF
A
Cfre
21
Q
Triple = SIM LF
A
Kpne
22
Q
Triple + SIM
A
Pvul
23
Q
Triple = SIM NLFs
A
Shigella
Yersinia
24
Q
Nonmotiles (35°)
A
Klebsiella
Yersinia
Shigella
25
The only = citrate LF
E. coli
26
Citrate, urease and PAD ===
E. coli
Shigella
Y. pestis
27
Arginine +
Citrobacter
Cronobacter
E. cloacae
28
The only A/L/O triple = LF
Pantoea agglomerans
29
ONPG + NLFs
Shigella sonnei
Yersinia
30
The only ases +
Smar
31
Koxy vs Kpne
Koxy indole +
Kpne indole =
32
Cfre vs Ckos
Cfre H2S +
Ckos H2s =
33
Pvul vs Pmir
Pvul indole +
Pmir indole =
34
Pret vs Pstu
Pret urea +
Pstu urea =
35
Y. pestis vs other Yersinia
Y. pestis urea =
other Yersinia urea +
36
Yent vs other Yersinia
Yent ornithine +
37
misleading nonpathogenic appearance on XLD and HE
Yersinia
38
Definition of Enterobacteriaceae (5)
GNR
Ox =
Glucose-fermenting
Grow on MAC
Nitrate +
39
3 enterics that are always pathogenic
Salmonella, Shigella and Yersinia
40
cytotoxin-producing E. coli
E. coli O157:H7
41
Infections caused by Enterobacteriaceae
UTI
Pyelonephritis
Diarrhea
Respiratory infection
Wound infections
Sepsis
42
BAP enteric colonies
Large wet, gray colonies
43
LPS causes...
shock, fever, hypotension, circulatory collapse, capillary hemorrhage, DIC
44
toxic part of LPS
lipid A
45
3 antigens used to differentiate Salmonella strains
K (capsule)
O (outer membrane)
H (flagellar)
46
---- is heat-labile and has to be boiled away to reach other antigens
K
47
K antigen present on Sent Typhi
Vi antigen
48
HE and XLD used to isolate ------ in stool
Salmonella
Shigella
49
CHO in HE agar
lactose, sucrose and salicin
50
2 pH indicators in HE
Brom-thymol blue
Acid fuchsin
51
Potential pathogens on HE
Colorless and take on green color of medium due to the lack of CHO fermentation
Black due production of hydrogen sulfide
52
Sugar fermented by Yersinia that gives a misleading HE result
sucrose
53
indicator in XLD
phenol red
54
CHO in XLD agar
lactose, xylose and sucrose
55
added to XLD to help detect salmonella
lysine
56
potential pathogens on XLD
Colorless and take on the red color of the medium (Shigella)
Black due to hydrogen sulfide production (Salmonella)
Red rimmed if lysine is decarboxylated (Salmonella)
57
present in TSI for H2S production
Sodium thiosulfate
58
pH indicator in TSI
phenol red
59
------- react with hydrogen sulfide gas to form a black precipitate
Iron salts
60
----- environment required to make H2S
acid
61
Mustache
S. enterica typhi
62
Explain indole reaction
Metabolism of the amino acid, tryptophan, creates indole, pyruvic acid and ammonia
63
para-dimethylaminobenzaldehyde
Ehrlich's or Kovac's reagent
used to detect indole
64
Indole spot can be performed on which agars?
SBA, CHOC
not MAC (no tryptophan present)
65
What does citrate determine?
Determines if organism is capable of using sodium citrate as the sole source of carbon for metabolism and growth (versus fermentation of carbohydrates)
66
Citrate pH indicator
Bromothymol blue
67
heavy inoculum for citrate can give false ------ results
positive
(bring over CHOs or dying organisms release C and N)
68
Urease indicator
phenol red
69
Explain urease reaction
Organisms that possess urease are able to hydrolyze urea to produce ammonia, creating alkaline pH
70
Explain PAD reaction
Determines the organism’s ability to deaminate phenylalanine to produce phenylpyruvic acid
71
VP + metabolic pathway
glycolysis -> pyruvate -> acetyl-methyl carbinol
72
MR + metabolic pathway
glycolysis -> pyruvate -> mixed acids at pH <4.4
73
------- can use both pathways, but the VP reaction can be delayed so it appears as MR+/VP= at 48 hours
Proteus
74
Why does VP give a false positive if read after 1 hour?
After 1 hour, KOH reacts with alpha-naphthol to produce a copper color
75
At 24 hours, all Enterics will give a ---- MR
+
76
2 types of positives for nitrate test
either the presence of one of the detectable end products, or the absence of nitrate
77
drop in pH required to turn on enzymes for Decarb reactions is accomplished by....
adding a small amount of glucose to the medium for fermentation
78
Decarb pH indicator
bromocresol purple
79
Forgetting to oil Decarb tubes gives a false ------
positive
80
ONPG long
Ortho-nitrophenyl-beta-D-galactopyranoside
81
ONPG detects...
Beta-D-galactosidase
82
If you can’t determine if LLF or NLF on MAC and do not have the ONPG result....
use TSI tubes
83
IMViC
Indole/MR/VP/Citrate
84
E. coli IMViC
+/+/=/=
85
Klebsiella IMViC
=/=/+/+
86
PAD +
Proteus
M. morganii
Providencia
87
Rapid E. coli ID (5)
Nonswarming GNR
Dark, dry LF
Spot indole +
Oxidase =
Beta-hemolytic
88
E. coli PYR
=
89
best test for lazy E. coli
serotyping
90
Most common cause of infections of the urinary bladder, renal pelvis and kidneys
E. coli
91
5 types of E. coli gastroenteritis
Enterotoxigenic (ETEC)
Enteroinvasive (EIEC)
Enteropathogenic (EPEC)
Enteroaggregative (EAEC)
Enterohemorrhagic (EHEC)
92
Profuse, watery diarrhea that is not bloody
Similar to Cholera
enterotoxigenic E. coli
93
Causes dysentery
Invades intestine like Shigella but organism does not leave the intestine to travel systemic in the body
enteroinvasive E. coli
94
Bind to cell and cause changes in the cell surface to produce lesions
Watery diarrhea with no blood and possibly a few WBCs
enteropathogenic E. coli
95
Several organisms bind together like a stack of bricks
Watery diarrhea but no blood or WBCs
enteroaggregative E. coli
96
Toxin destroys intestinal microvilli and damages vascular endothelium to produce bloody diarrhea without WBC
enterohemorrhagic E. coli
97
E. coli strain causing EHEC
Shiga-toxin producing E. coli (STEC)
98
About 4% of EHEC cases progress to...
hemolytic uremic syndrome (HUS)
99
Tx for HUS
do NOT use Ab (more LPS released)
100
Best method to dx EHEC
Shiga-toxin detection in stool via molecular methods
101
Unique about O157:H7
does not ferment sorbitol
102
SMAC used to...
differentiate O157:H7, which does not ferment sorbitol
103
enzymes for Ab resistance in Klebsiella
Extended spectrum beta-lactamase (EXBL)
Klebsiella pneumoniae carbapenemase (KPC)
104
Klebsiella colonizes...
URT of hospitalized patients
105
Bloody jelly sputum
Necrotizing pneumonia
Klebsiella
106
unusual sites of infection, potential for metastatis
hypervirulent Klebsiella
107
Hypermucoviscous colonies
hypervirulent Klebsiella
108
Common nosocomial organism in ICU
enterobacter
109
AmpC
enzyme
organism
induced by...
cephalosporinases
Enterobacter
cefoxitin, imipenem and ampicillin
110
pigment of Cronobacter sakazakii
yellow
111
Can survive under very dry conditions, like powdered infant formula, and cause neonatal meningitis/sepsis
Cronobacter sakazakii
112
red pigment of Smar indicates (high/low) virulence
low
113
Smar colonizes...
hospital patients’ respiratory and urinary tracts
especially after respiratory instrumentation and catheters
114
LLF with high MDR
Smar
115
1970’s nationwide outbreak of septicemia due to IV fluid contaminated with...
Pagg endotoxin
115
Pagg pigment
light yellow
116
causes most Proteus infections
Pmir
117
Kidney stone formation
Proteus
118
Seen primarily in those with long-term indwelling urinary catheters
Pstu
119
Poultry and reptile pathogen
Prett
120
Citrobacter is serologically similar to....
Salmonella
121
2400 serotypes based on the Kaufmann-White scheme
Salmonella
122
S. enterica Typhi is serotype ---
D
123
Salmonella
124
Differentiates Typhi serotype from other Salmonella
TSI mustache
125
5 F's for spreading Salmonella
Friends, flies, fingers, food, feces
126
Typhoid fever has a (high/low) infectious dose
low
(other Salmonella infections are high)
127
High fever and constipation with positive Salmonella blood cultures but negative stool cultures
week 1-2 of typhoid fever
128
Invades peyer’s patches (lymph nodes) of ileum then invades liver, spleen, lymph nodes , bone marrow and gallbladder
week 2-3 of typhoid fever
129
Diarrhea phase (similar to pea soup) with negative blood cultures and positive stool cultures
week 3 of typhoid fever
130
carries of Sent Typhi have organisms hiding in the....
gallbladder
131
Nontyphoidal Salmonella tx
Often resolves in 5-7 days without treatment
Fluid and electrolyte replacement
Antibiotics do not shorten the course of the disease
132
Groups of Shigella O antigen serotypes
S. dysenteriae – group A
S. flexneri – group B
S. boydii – group C
S. sonnei – group D
(dead flies on boy scouts)
133
Shigella has a (high/low) infectious dose
low
134
disease of armies
Shigella
135
Bloody diarrhea with WBC (dysentery)
Shiga toxin
Shigella and E. coli
136
Most dysentery is due to -------, but the most severe is due to ------
S. sonnei
S. flexneri
S. dysenteriae
137
Retains methylene blue or Wayson stain at ends of rods
Safety pin
Yersinia pestis
138
Yersinia pestis
139
how to select/differentiate for Yersinia
CIN (Cefsulodin, Irgasan, Novobiocin) agar at room temperature
140
Yersinia appearance on CIN
bull's eye
141
3 forms of plague
bubonic
pneumonic
septicemic (black death)
142
Contaminates swine food products
Infects Peyer's patches
Y. enterocolicita
143
Mimics appendicitis
Y. enterocolitica
144
High risk individuals for septicemia from Yent
Iron overload
145
Yersinia on CIN
146
uses a mixture of colored beads to serotype Salmonella and Shigella
Wellcolex Colour kit
147
mini biochemicals for enterics
API20E
148
test that follows a suspicious SMAC
latex agglutination for O157:H7
149
transmission of the 3 types of plague
bubonic—Organism from flea bite travels to the lymph nodes inside macrophages
pneumonic—Direct exposure to respiratory droplets
septicemic—Organism is inoculated directly into bloodstream via flea bite or spread from lymph nodes
