ENTEROBACTERIACEAE Flashcards
(199 cards)
1
Q
Enterobacterias are commensal floras of the…
A
Intestinal tract
2
Q
Enterobacterias that are not part of a normal flora
A
Salmonella
Shigella
Yersinia
3
Q
Microscopic appearance of Enterobacterias
A
Gram-negative straight rods or coccobacilli with rounded ends
4
Q
Culture morphology of Enterobacterias
A
Large, smooth, gray colonies (except Klebsiella and Enterobacter)
Non hemolytic (except E. Coli - beta hemolytic)
5
Q
Characteristics of Enterobacteriaceae
A
Gram negative straight rods or coccobacilli
Non hemolytic (except E. Coli - beta hemolytic)
Motile (except Klebsiella, Shigella, and Yersinia)
Non encapsulated (except Klebsiella, and Enterobacter)
Glucose fermenter
Reduce nitrate to nitrite
Some may grow at low temperature: 1-5ºC (Serratia and Yersinia)
6
Q
Non motile Enterobacteriaceae
A
“SKY”
Shigella
Klebsiella
Yersinia
7
Q
Motility organelle used by Enterobacterias
A
Peritrichous flagella
8
Q
Encapsulated Enterobacterias
A
Klebsiella
Enterobacter
9
Q
Enterobacterias that grow at low temperatures (1-4ºC)
A
Yersinia
Serratia
10
Q
Gram negative cocci
Catalase (+)
Cytochrome oxidase (+) (except Plesiomonas shigelloides)
Alginate liquefaction (+)
A
Enterobacteriaceae
11
Q
Opportunistic Enterobacteriaceae pathogen
A
“PECKS”
Proteus
Enterobacter
Citrobacter
Klebsiella
Serratia
12
Q
Overt/true Enterobacteriaceae pathogen
A
Salmonella typhi
Shigella
Yersinia pestis
13
Q
They are part of the intestinal microbiota of both humans and animals but may produce serious extraintestinal diseases when outside their normal body sites
A
Opportunistic pathogens
14
Q
They are not present as commensal flora of the GIT of humans and only inhabit the bowel at the time of infection. They are generally acquired through ingestion of contaminated food or water.
A
Overt/True pathogens
15
Q
Extended-spectrum-B-lactamase-producing Enterobacterias
A
“EKKstended-…”
Escherechia coli
Klebsiella pneumonia
Klebsiella oxytoca
16
Q
Isolated from urinary tract and cause bacteremia
A
“PEK”
Proteus mirabilis
Escherichia coli
Klebsiella pneumoniae
17
Q
Antibiotic-resistant genera of Enterobacteriaceae
A
“SEC”
Serratia
Enterobacter
Citrobacter
18
Q
Enterobacteria associated with diarrhea
A
“YESS”
Yersinia
Escherichia coli
Salmonella
Shigella
19
Q
Antigen determinants used for serological identification of Enterobacterias
A
“O” antigen
“H” antigen
“K” antigen
20
Q
“O” antigen or…
A
Somatic antigen
21
Q
“H” antigen or…
A
Flagellar antigen
22
Q
“K” antigen or…
A
Capsular antigen
23
Q
Heat stable antigen; located in the cell wall
A
“O” antigen
24
Q
Heat labile antigen; found in the flagellum
A
“H” antigen
25
Heat labile polysaccharide; covers the O antigen
“K” antigen
26
Which bacterias are serotyped with “O” antigens
Escherichia coli
Shigella
27
Which bacterias are serotyped with “H” antigen
Salmonella
28
Which bacterias are serotyped with “K” antigen
Escherichia coli
S. enterica subsp. enterica serotype Typhi
29
Possesses “K1” capsular antigen
E. coli
30
Possesses “Vi” capsular antigen
S. enterica subsp. enterica serotype Typhi
31
Aka colon bacillus
Escherichia coli
32
Where is Escherichia coli found in humans?
Normal bowel flora
Female genital tract
33
It invades enterocytes lining the large intestine
Escherichia coli
34
It is a primary marker of fecal contamination in water purification
Escherichia coli
35
It is the leading cause of nosocomial infection — UTI
Escherichia coli
36
Flat, dry, with pink colonies (MAC)
Beta hemolytic (BAP)
Some strains may be NLF or LF
Greenish metallic sheen (EMB)
Escherichia coli
37
E. coli “O” groups have shown cross reactivity with ___________
“O” antigens of Shigella
38
Antigenic determinants on Escherichia coli
O, H, K antigens
39
Escherichia coli virulence factors
“ECoKI” ~sounds like E. coli~
Endotoxin
Common pili
K1 antigen
Intimin
40
Escherichia coli virulence factor responsible for neonatal meningitis
K1 antigen
41
Identical to the capsular antigen on Neisseria meningitidis group B
K1 antigen
42
Escherichia coli IMVIC and TSI reaction
IMVIC: + + - -
TSI: A/A, (+) gas, (-) H2S
43
Formerly called E. coli atypical or enteric group II
Escherichia hermanii
44
Escherchia with yellow pigmented colonies
Escherichia hermanii
45
E. coli strain that does not produce toxin and only attaches to the brush border of the intestinal epithelial cells causing cell damage
Enteropathogenic E. coli
46
E coli strain causing infantile diarrhea (stool without blood)
Enteropathogenic E. coli
47
E coli strain with H antigen and intimin
Enteropathogenic E. coli
48
Colonizes the proximal small intestine, causing Traveler’s diarrhea or montezuma’s revenge
Enterotoxicogenic E coli
49
Persons with achlorhydia are at risk of getting this E coli strain
Enterotoxicogenic E coli
50
Enterotoxicogenic E coli virulence factor
Heat stable (ST) and heat-labile (LT) enterotoxin
51
Infective dose of Enterotoxicogenic E coli
10^6 to 10^10
52
E coli strain that penetrates and multiplies within the intestinal epithelial cells, causing dysentery-like or shigella-like infections
Enteroinvasive E coli
53
Infection with this E coli strain produces watery diarrhea with WBC
Enteroinvasive E coli — dysentery-like or shigella-like infection
54
Enteroinvasive E coli virulence factor
Invasin
55
E. coli strain positive for Sereny test
Enteroinvasive E coli
56
Infective dose of Enteroinvasive E coli
10^6
57
Associated with hemolytic uremic syndrome an thrombotic thrombocytopenia purpura
Enterohemorrhagic E coli serotype 0157:H7
58
What strain and its toxin is responsible for the destruction of vascular endothelial cells which cause hemorrhagic colitis, and hemolytic uremic syndrome (HUS)?
Verotoxin present in Enterohemorrhagic E coli
59
Shiga-like toxin
Verotoxin
60
Causes infection with bloody diarrhea (without WBC)
Enterohemorrhagic E coli
61
Shigella-like toxin E coli
Enteroinvasive E coli
Enterohemorrhagic E coli
62
E coli strain with (+) intimin; (-) MUG
Enterohemorrhagic E coli
63
2 types of Enteroadherent E coli
Enteroadherent E coli (EAEC)
Diffusely adherent E coli (DAEC)
64
E coli strain that adheres to the surface of the intestinal mucosa and causes watery diarrhea, or UTI
Enteroadherent E coli
65
E coli strain that adheres to Hep2 cells forming clumps of bacteria and causes UTIs
Diffusely adherent E coli
66
Enteroadherent E coli virulence factor
Fimbriae
67
Causes “stacked-brick” appearance of clumped bacterias
Diffusely adherent E coli
68
Most common cause of UTIs in humans
Uropathogenic E coli
69
Uropathogenic E coli virulence factor
“PAC”
Pili
Aerobactin
Cytolysin
70
A test used to test the invasiveness of enteroinvasive Escherichia coli, Shigella species, and Listeria monocytogenes. It is done by inoculating suspension of bacteria into guinea pig's eye. Severe mucopurulent conjunctivitis and severe keratitis indicates a positive test.
Sereny test
71
Bacterial adhesion molecule involved in attachment of enteropathogenic and enterohaemorrhagic Escherichia coli to mammalian host cells
Intimin
72
Vibrio-like E coli
Enterotoxigenic E coli
73
___________ activates guanylate cyclase which stimulates the production of __________
Heat-stable enterotoxin (ST)
Cyclic guanosine monophosphate (cGMP)
74
Induces the secretion of electrolytes and water into the lumen of the intestine resulting to watery diarrhea
Cyclic guanosine monophosphate (cGMP)
Cyclic adenosine monophophate (cAMP)
75
_________ binds to specific gangliosides on the epithelial cells and activates membrane bound adenylate cyclase, which leads to increased production of ________
Heat-labile enterotoxin (LT)
Cyclic adenosine monophosphate (cAMP)
76
AKA Shiga toxicogenic E. coli
Enterohemorrhagic E. coli
77
Biochemical characteristics of Klebsiella
KCN (+)
H2S (-)
MR (-)
VP (+)
78
Friedlander’s bacillus
Klebsiella pneumoniae subsp. pneumoniae
79
Formerly known as the bacillus capsulatus
Klebsiella pneumoniae subsp. pneumoniae
80
The most common isolated spp of Klebsiella
Klebsiella pneumoniae subsp. pneumoniae
81
Causative agent of community acquired pneumonia
Klebsiella pneumoniae subsp. pneumoniae
82
Causes currant jelly-like sputum
Klebsiella pneumoniae subsp. pneumoniae
83
It is a frequent cause of lower respiratory tract infections among hospitalized patients and in immunocompromised hosts
Klebsiella pneumoniae subsp. pneumoniae
84
Pink, mucoid colonies (MAC)
Neufeld Quellung test (+)
TSI: A/A, (+) gas, (-) H2S
IMVIC (- - + +)
KCN (+)
Urease (+)
Lysine decarboxylase (+)
Gelatin @ 22ºC (-)
Na alginate utilization (+)
Klebsiella pneumoniae subsp. pneumoniae
85
Virulence factor of Klebsiella pneumoniae subsp. pneumoniae
Polysaccharide capsule
86
Differential test for Klebsiella pneumoniae subsp. pneumoniae
String test (+)
87
Causes chronic atrophic rhinitis (“foul smelling” atrophic rhinitis)
Klebsiella pneumoniae subsp. ozanae
88
Causes a granuloma of the nose and oropharynx
Klebsiella pneumoniae subsp. rhinoscleromatis
89
Klebsiella species that are indole positive
K. oxytoca
K. ornithinolytica
90
Biochemical test:
IMVIC (+ + + +)
Urease (+)
Lysine decarboxylase (+)
Gelatin @ 22ºC (-)
Klebsiella oxytoca
91
Resembles Klebsiella on MAC: pink colonies and maybe mucoid colonies
Enterobacter
92
Has been isolated with osteomyelitis following traumatic wounds
Enterobacter cancerogenous
93
A pathogen in neonates causing meningitis and bacteremia, often coming from powdered infant formula
Culture: yellow-pigmented colonies
Cronobacter sakazaki
94
Causes nosocomial outbreak of septicemia due to contaminated IV fluids. It shows “triple decarboxylase negative” reaction
Pantoea agglomerans
95
Musty-pungent odor or “potato-like” odor
Serratia odoriferae
96
Most clinically significant Serratia spp.
Serratia marcescens
97
Causes bacteremic outbreaks in nurseries and cardiac surgery and burn units. It is a contaminant in antiseptic solutions used for joint injections causing an epidemic of septic arthritis
Serratia marcescens
98
Causes osteomyelitis following a motorcycle accident
Serratia plymuthica
99
It is not known to cause gastroenteritis but is occasionally isolated from stool cultures. It has a distinctive feature: delayed citrate reaction.
Hafnia alvei
100
It can infect the proximal kidney tubules and can cause AGN particularly in patients with urinary tract defects or catheterization.
Proteus
101
Culture:
“swarming phenomenon” and “burn chocolate” or “burnt-gun powder” odor
Proteus
102
Common isolates of Proteus
Proteus mirabilis
103
Proteus that is a human pathogen
Proteus mirabilis
Proteus vulgaris
104
TRUE OR FALSE
The swarming phenomenon is a result of a tightly regulated cycle of differentiation from standard vegetative cells (swimmers) to hyperflagellated, elongated, polyploidy cells (swarmers) capable of coordinated surface movement
TRUE :’)
105
Is a rapid urease producer which encourages renal stone formation (urea splits in urine = increased urine pH). It is isolated from urine, wound, and ear infections.
Proteus
106
Biochemical characteristics of Proteus
PAD test (+)
LIA (R/A)
IMVIC: (- + v v) P mirabilis; (+ + - v) P vulgaris
TSI: K/A, (+) gas, (+) H2S - P mirabilis
K/A, (+/-) gas, (+) H2S - P vulgaris
107
One of the causes of nosocomial outbreaks involving burn units.
PAD test (+)
IMVIC (+ + - +)
TSI: K/A, (-) gas, (-) H2S
Providencia
108
A pathogen of the urinary tracts that also causes diarrheal disease among travelers
Providencia rettgeri
109
It has been isolated from noscomial outbreaks in burn units and in urine cultures. It is mostly resistant to antimicrobial agents (together with P rettgeri)
Providencia stuartii
110
Providencia spp most commonly found in the feces of children with diarrhea
Providencia alcalifaciens
111
Differentiates P rettgeri from P stuartii
Christensen’s urea: (+) P rettgeri ; (-) P stuartii
112
Biochemical characteristics of Morganella
Same biochemical reaction with P vulgaris except citrate (-)
PAD test (+)
LIA (R/A)
IMVIC (+ + - -)
TSI: K/A, (+/-) gas, (+) H2S
113
Edwardsiella spp pathogenic to humans
Edwardsiella tarda
114
It has been isolated from cold-blooded and warm blooded animals
Biochemical test:
Urease (-)
LDC (+)
IMVIC ++—
TSI K/A, (+) gas, (+) H2S
Edwardsiella
115
A plant pathogen enterobacteriaceae not significant in human infections
Erwinia
116
Colonies on MAC resemble E coli and biochemically resembling Salmonella. It can cause false (+) agglutination test with salmonella
Citrobacter
117
Has been associated with endocarditis in IV drug users. The colony morphology resembles Salmonella when isolated from stool cultures.
Citrobacter freundii
118
It produces type 1 cephalosporinase
Citrobacter freundii
119
It causes nursery outbreaks of neonatal meningitis and brain abscesses
Citrobacter koseri
120
The most serous pathogenic Enterobacteria for humans
Salmonella
121
An inhabitant of the GI tract of animals. Humans acquire this organism by ingestion of contaminated animal products or improperly cooked poultry, milk, eggs, and dairy products. It may also be transmitted by “human carriers”
Salmonella
122
Salmonella biochemical characteristics
Motile (except S pullorum and S gallinarum)
Gas (+) (except S gallinarum and S typhi)
H2S (+) (except S paratyphi A)
LDC (+)
KCN (-)
IMVIC (-+-+ / -+—) S typhi
TSI: K/A, (+/-) gas, (+) H2S
123
Salmonella virulence factor
Fimbriae
Enterotoxin
124
Main etiologic agent of enteric fever
Salmonella typhi
125
Etiologic agents of paratyphoid fever
Salmonella paratyphi A, B, C
Salmonella choleraesuis
126
Salmonella isolated from lizards and other cold-blooded animals
Salmonella bongori
127
Most common Salmonella strain associated with gastroenteritis delete
Salmonella enterica subsp. enterica
128
Causes peanut-butter outbreak
Salmonella typhimurium
129
Diseases caused by Salmonella
Gastroenteritis
Typhoidfecer
Bacteremia
130
Gastroenteritis is one of the most common forms of “food poisoning.” This is spread by using contaminated cooking utensils. Inadequate refrigeration also allows the growth and multiplication of the organism. Poultry, eggs, milk, and handling of pets are the main source of infection. Symptoms include nausea, vomiting, fever and chills, watery diarrhea and abdominal pain.
What is the causative agent?
Salmonella enterica subsp enterica
131
Infective dose of Salmonella enterica
10^6
132
A febrile disease that results from the ingestion of contaminated food originating from infected individual or carriers, contaminated food and water, and fomites. Outbreaks can also be caused by improper disposal of sewage, poor sanitation and lack of modern water system. Symptoms include malaise, anorexia, lethargy, myalgia, and continuous frontal dull headache.
Enteric fever/typhoid fever
133
Causative agent of typhoid fever
Salmonella typhi
134
Characteristic papules that appear during the second week of typhoid fever
“Rose spot” blanching rose-colored papules that appear around the periumbilical region
135
The site of long-term carriage of Salmonella typhi for individuals who have recovered from the infection
Gall bladder
136
Causes necrotizing cholecystitis and Peyer’s patches
Salmonella typhi
These are the complications of typhoid fever
137
Salmonella resistant to gastric acids and, on reaching the proximal end of the small intestine, invades and penetrates the intestinal mucosa
Salmonella typhi
138
Characterized by prolonged fever and intermittent bacteremia. This occurs with and without extraintestinal foci of infection caused by nontyphoidal Salmonella.
Bacteremia
139
Salmonella responsible for bacteremia
Non typhoidal salmonella: S typhimurium, S paratyphi, and S cholerasuis
140
Treatment for chronic state of enteric carriers
Cholecystectomy is the only remedy
141
What specimen for salmonella id is collected for the 1st week of infection?
Blood
142
What specimen for salmonella id is collected for the 2nd week of infection?
Stool
143
What specimen for salmonella id is collected for the 3rd week of infection?
Urine
144
Closely related to genus Escherichia. It is an intracellular organism that multiplies in the cells of the colon epithelium.
Shigella
145
Mode of acquisition of Shigella
Flies, fingers, food and feces (the four F’s) and water by infected persons (fecal-oral route)
146
Culture:
Clear, fragile, NLF colonies
colorless colonies without black centers (SSA)
Shigella
147
Shigella reservoirs
Humans only
148
Most virulent Shigella species
Shigella dysenteriae
149
Gay bowel syndrome
Shigella flexneri
150
Shigella virulence factor
Shiga toxin
151
Shigella antigenic structures
Somatic O
152
Shigella specimen
Rectal swab
153
Shigella biochemical characteristics
Non motile
Mannitol fermenter (except Shigella dysenteriae)
Does not utilize acetate or mucate as source of carbon
(-) gas from glucose (except Shigella flexneri)
Urease (-)
LDC (-)
IMVIC (v+—)
TSI: K/A, (-) gas, (-) H2S
154
Susceptible to disinfectants and high concentrations of acids and bile
Shigella
155
Why are Shigella specimens plated immediately after collection
Shigella is sensitive to pH changes (susceptible to acidic stool)
156
Is unique in its ability to decarboxylate ornithine; late lactose fermenter; ONPG (+)
Infection from this organism is self-limiting and usually characterized by fever and watery diarrhea
Shigella sonnei
157
Most common causative agent of bacillary dysentery
Shigella dysenteriae type 1
158
Characterized by acute inflammatory colitis and bloody diarrhea (blood mucus, and WBCs) caused by the penetration of the intestinal epithelial cells by the organism, following attachment of the organisms to mucosal cell. Symptoms include fever, chills, abdominal cramps, painful bowel movement, and tenesmus.
Bacillary dysentery
159
Its presence usually indicates improper sanitary conditions and poor personal hygiene
Shigella dysenteriae type 1
160
Infective dose of Shigella dysenteriae
<200 bacilli
It is highly communicable because of its low infective dose required to produce the disease
161
AKA plague bacillus
Yersinia pestis
162
Yersinia pestis is considered as a ________ bioterrorism agent
Class A bioterrorism agent
163
The only Enterobacteriaceae transmitted to humans by the bite of an infected flea
Yersinia pestis
164
Vector of transmission for Yersinia pestis
Xenopsylla cheopis
165
Where do Yersinia pestis multiply?
Inside phagocytes
166
Protein responsible for the down-regulation of anti-bacterial responses of the host which allows Yersinia pestis to survive and multiply inside phagocytes
Yersinal plasmid-encoded outer membrane proteins (YOPS)
167
Microscopic appearance of Yersinia pestis
Short, plump rod with “bipolar staining or closed safety pin appearance”
168
Stain used for Yersinia pestis
Wayson or methylene blue stain
169
Culture morphology of Yersinia pestis
Pinpoint colonies; grows best at 25º-30º C
Stalactite pattern (broth culture)
170
Yersinia pestis virulence factor
Endotoxin
Coagulase
Fibrinolysin
171
Mode of transmission of plague
Is a disease of the rodents transmitted to humans by fleas
Ingestion of contaminated animal tissues
Inhalation of contaminated airborne droplets
Once inside the human body, the bacteria multiplies in the blood and lymph
172
2 forms of plague
Bubonic plague
Pulmonary plague
173
Associated with high fever and painful inflammatory swelling of axilla and groin. It results from the bite of an infected flea
Bubonic plague
174
Occurs secondary to the bubonic plague. It is acquired by close contact with other victims.
Pulmonary plague
175
The most commonly isolated Yersinia
Yersinia enterocolitica
176
Causative agent of waterborne gastroenteritis
Yersinia enterocolitica
177
How is Yersinia enterocolitica isolated from a stool specimen?
Requires cold enrichment technique (4ºC) using phosphate buffered saline for several weeks
178
Biochemical characteristics of Yersinia enterocolitica
Motile at 22ºC but not at 35ºC
Ferments sucrose and mannitol
IMVIC (v+—)
TSI: K/A, (-) gas, (-) H2S
179
Microscopic appearance of Yersinia enterocolitica
Coccobacilli with bipolar staining
180
Culture morphology of Yersinia enterocolitica
“Bull’s eye colonies” (dark red or burgundy centers with transparentborders) in CIN medium
181
Optimum temperature for Yersinia enterocolitica
25º-30ºC
182
Selective medium for Yersinia enterocolitica
Cefsulodi-irgasan-novobiocin (CIN) agar
183
Yersinia enterocolitica reservoir
Swine
Dogs
Cats
Rabbits
Cattle
184
Infections caused by Yersinia enterocolitica
Enterocolitis — waterborne gastroenteritis
Appendicitis-like syndrome
Arthritis
Erythema nodosum
185
Yersinia enterocolitica mode of acquisition
Consumption of incompletely cooked food and dairy products, and handling pets
186
A pathogen of rodents, particularly guinea pigs
Yersinia pseudotuberculosis
187
Yersinia pseudotuberculosis reservoir
Farm and domestic animals (birds)
188
Yersinia pseudotuberculosis mode of acquisition
Close contact with infected animals on their fecal material and ingestion of contaminated drink and food
189
Biochemical characteristic of Yersinia pseudotuberculosis
Motile at 18º-25ºC
Urease (+)
Ferments rhamnose
190
At what temperature is Yersinia pseudotuberculosis motile?
18º-25ºC
191
At what temperature is Yersinia enterocolitica motile?
22ºC but not at 35ºC
192
Antigens present in Yersinia enterocolitica
V and W antigens
193
At what temperature is Yersinia pestis motile?
They are nonmotile
194
The only oxidase (+) member of Enterobacteriaceae
Plesiomonas shigelloides
195
Microscopic appearance of Plesiomonas shigelloides
Gram negative straight bacilli; occurs singly, in pairs, short chains or filamentous forms
196
Culture morphology of Plesiomonas shigelloides
Shiny, opaque, smooth, and nonhemolytic (BAP)
white to pink colonies (Inositol brilliant green bile salt agar)
Opaque "apron-like colonies" (CIN)
(-) growth on TCBS
(+) growth on HEA
197
Plesiomonas shigelloides morphology on CIN
Opaque "apron-like" colonies
198
Often cross-agglutinates with Shigella
Plesiomonas shigelloides
199
Plesiomonas shigelloides antigenic structures
Somatic O
Flagellar H (polar flagella)
