Enterobacteriaceae Flashcards
1
Q
Which species are non-motile?
A
Klebsiella, shigella, and yersinia
2
Q
Which specie is catalase negative?
A
Shigella dysenteriae type 1
3
Q
Which specie is oxidase positive?
A
Plesiomonas
4
Q
Which species are encapsulated?
A
- klebsiella
- enterobacter
5
Q
Most commensal of GI tract except
A
- plesiomonas
- salmonella
- shigella
- yersinia
6
Q
May grow at 1-5 degrees celsius
A
- serratia
- yersinia
7
Q
Do not produce cytochrome oxidase except
A
Plesiomonas
8
Q
What is the colony morphology of enterobacteria in gram stain?
A
Gram negative coccobacilli
9
Q
This media has no value for initial identification of enterobacteria
A
SBA or CAP
10
Q
Which species grows large and very mucoid in SBA and CAP?
A
Klebsiella (sometimes enterobacter)
11
Q
Enumerate the selective and differential media
A
EMB - Eosin Methylene Blue
MAC - MacConkey agar
HEA - Hektoen Enteric Agar
XLD - Xylose-Lysine Desoxycholate
12
Q
These are highly selective medium
A
Hektoen Enteric Agar
Xylose-Lysine Desoxycholate
13
Q
HEA AND XLD contains _____ which produce blackening of hydrogen sulfide
A
Sodium thiosulfate and ferric ammonium citrate
14
Q
Lack of color change and colonies retain origu al color of medium
A
Non-fermenting
15
Q
Indicated by a color change on the medium — results from a decrease in pH detected by a pH indicator incorporated into the medium
A
Fermentation
16
Q
What is the most important media used to differentiate lactose fermenter and non-lactose fermenter?
A
MacConkey agar
17
Q
What is the color of LF in MAC?
A
Pink colony appearance
18
Q
What is the color of NLF in MAC?
A
Colorless colony appearance
19
Q
What other selective and differential media used to isolate distinguishes between LF and NLF?
A
- Eosin methylene blue
- Salmonella Shigella agar
- Triple Sugar Iron
- MacConkey agar (most important)
20
Q
Enumerate lactose fermenter bacteria
A
- Escherichia coli
- Klebsiella
- Enterobacter
- Serratia
- Citrobacter
21
Q
Enumerate non-lactose fermenter bacteria
A
MESSHPPY
- morganella
- edwardsiella
- salmonella
- shigella
- hafnia
- proteus
- providencia
- yersinia
22
Q
Enumerate members of coliform bacilli AND what is the most common member of it?
A
- e. coli
- klebsiella
- enterobacter
- citrobacter
> E. coli (most common member)
23
Q
Often a part of the usual intestinal microbiota of both humans and animals
A
Opportunistic pathogens
24
Q
Heat labile antigen found on the surface of flagella
A
H antigen
25
Heat stable antigen located on the cell wall
O antigen
26
Heat labile polysaccharide found only in certain encapsulated species
K antigen
27
O antigen also known as
Somatic antigen
28
H antigen also known as
Flagellar antigen
29
K antigen also known as
Capsular antigen
30
Give example of K antigen
- K1 antigen found in E. Coli
- Vi antigen
31
Biochemical testing was originally done in ______ which is more accurate
Test tube
32
Ability to ferment glucose, lactose, and sucrose and to produce hydrogen sulfide
Triple sugar iron
33
What is the composition of TSI
1% lactose, 1% sucrose, 0.1% glucose
34
Similar to TSI but only incorporates the carbohydrate glucose and lactose
KIA - Kligler’s Iron agar
35
What is the incubation period of TSI and KIA?
18-24 hours
36
Red slant / red butt
No fermentation
Alk/alk
K/k
37
Red slant / yellow butt
Glucose fermentation only
K/A
38
Yellow slant / yellow butt
Lactose fermenter
A/A
39
Blackening of the medium
H2s production
40
With gas production
Aerogenic
41
No gas production
Non-aerogenic
42
Bubbles or splitting in the agar
Gas production
43
Enumerate the biochemical test in IMVIC
- indole test
- methyl red test
- voges proskauer test
- citrate utilization test
44
Test the ability of the bacteria to produce the enzyme tryptophanase and deaminate tryptophan to indole, pyruvic acid, and ammonia
Indole test
45
What is the enzyme of indole test?
Tryptophanase
46
What is the component of indole test?
PDAB - para-dimethyl-aminobenzaldehyde
47
What are the two reagents of indole test?
- Ehrlich’s reagent
- kovac’s reagent
48
What is the positive reaction of indole test?
Red ring at the top
49
What is the positive reaction of methyl red
Red color
50
What is the negative reaction of methyl red?
Yellow
51
It measures the productiin of acetoin after the addition of alphanapthol followed by 40% potassium hydroxide or sodium hydroxide
Voges proskauer test
52
What is the positive reaction for voges proskauer test?
Red complex
53
Determines whether an organisms can use sodium citrate as a sole carbon source
Citrate utilization test
54
Nitrogen source in the medium and utilization of these salts results in the release of ammonia causing pH change
Ammonium salts
55
What is the pH indicator of SCA
bromothymol blue
56
Determines whether an organism has the ability to reduct nitrate to nitrite
Nitrate reduction test
57
What is the positive reaction of nitrate reduction test?
Red color
58
Determines the presence of cytochrome oxidase system that oxidizes reduced cytochrome with molecular oxygen
Oxidase test
59
What biochemical test used to differentiates enterobacteriaceae from pseudomonads?
Oxidase test
60
Determines whether a microorganisms can hydrolyze urea releasing a sufficient amount pf ammonia to produce a color change by a pH indicator
Urease test
61
What is the medium used for urease test?
Christensen’s Urea agar
62
What is the positive reaction of urease test?
Bright pink color
63
What biochemical test used to differentiate proteus from other enteric bacteria?
Urease test
64
What is the positive reaction of Gelatin Hydrolysis test?
Liquefaction of the gelatin
65
What is the positive reaction of oxidase test?
Purple
66
Bacteria that produce gelatinases that break down gelatin into amino acids
Gelatin Hydrolysis Test
67
Utilizes the sodium thiosulfate source to form H2s, a colorless gas -H2s combines with the indicator ferrous sulfate
Hydrogen sulfide production
68
What are the media that can be used for h2s test?
SIM - sulfide indole motility
Salmonella Shigella agar
Hektoen Enteric agar
TSI
KIA
LIA
69
What is the agar concentration for motility test?
0.4% agar
70
What is the routine medium used for motility test?
SIM
71
What is the positive reaction of motility test?
Movement away the stab line or hazy appearance
72
Enumerate the amino acid utilization
- Decarboxylase and Dihydrolase test
- PAD test (Phenylalanine deaminase test)
73
Determine whether the bacterial species possess enzymes capable of decarboxylating specific amino acid in the test medium
Decarboxylase and dihydrolase tsst
74
What are the two amino acids commonly used?
Lysine and ornithine
75
What are the products of decarboxylation?
Amine or diamine
76
Lysine decarboxylase
Cadaverine
77
Ornithine decarboxylase
Putrescine
78
What are the media that can be used in decarboxylase and dihydrolase test?
LIA, Motility indole ornithine, moeller decarboxylase base medium
79
What is the positive reaction for decarboxylase and dihydrolase test?
Purple
80
What is the negative result for decarboxylase and dihydrolase test?
Yellow
81
Determines whether an organisms possesses thr enzyme that deaminates phenylalanine to phenylpyruvic acid
Phenylalanine deaminase test
82
What is the reagent used in PAD test?
10% ferric chloride
83
What is the positive reaction of PAD test?
Green color
84
What bacteria are pisi tube in PAD test?
Proteus, providencia, and morganella
85
Used primarily to determine whether the bacteria decarboxylate or deaminate lysine
Lysine iron agar
86
What media are used to differentiate salmonella from citrobacter?
Lysine iron agar
87
What media are used to differentiate proteus, morganella, and providence from other enterobacteriaceae?
LIA
88
What is the ph indicator of LIA?
Bromocresol purple
89
What is the most significant species in the genus Escherichia?
Escherichia coli or colon bacillus
90
What is the morphology of e. coli when inoculated in MAC?
Pink colonies
91
What is the morphology of e. coli when inoculated in EMB?
Greenish metallic sheen
92
E. Coli
IMVIC
Indole positive
Methyl red positive
Voges proskauer negative
Citrate negative
Does not produce h2s, dnase, urease, or PAD test
93
What is the strain of E. Coli that is considered as the most common cause of UTIs in humans?
UPEC - Uropathogenic E. Coli
94
What are the two pathogenic strains of E. Coli?
- Uropathogenic e. coli (UPEC)
- Enterovirulent or Diarrheogenic e. coli
95
Primary virulencr factor associated with the ability of E. Coli to cause UTIs
Pili
96
Based on virulence factors clinical manifestations epidemiology and different O and H serotypes
Enterovirulent or diarrheogenic e. coli
97
Associated with diarrhea of adults and especially children in tropical and subtropical climates
Enterotoxigenic e. coli (ETEC)
98
Causes “infantile diarrhea”
Enteropathogenic e. coli (EPEC)
99
Enterotoxigenic e. coli is the most common cause of diarrheal disease also referred to as
Traveler’s diarrhea
100
Deficiency of hydrochloric acid within the stomach
Achlorydia
101
Pathogenic strain of e. coli produces shiga-like toxins
EHEC - Enterohemorrhagic e. coli
102
characterized by watery diarrhea, abdominal cramps, nausea usually with no vomit or fever
ETEC - Enterotoxigenic e. coli
103
Characterized by low-grade fever, malaise, vomiting and diarrhea
EPEC - Enteropathogenic e. coli
104
Outbreak occurs in hospital nurseries and daycare centers
EPEC
105
Characterized by fever, severe abdominal cramps, malaise and watery diarrhea
EIEC - EnteroInvasive E. Coli
106
Produce dysentery with direct penetration, invasion, and destruction of the intestinal mucosa
EIEC
107
It was first recognized during the outbreak of hemorrhagic diarrhea and colitis
EHEC
108
What is the carbohydrate used in MAC for primary screening test in enterohemorrhagic e. coli?
Sorbitol
109
Most common cause of septicemia and meningitis in neonates
Extraintestinal infections
110
Most documented virulencr factor associated with neonatal meningeal infections
K1 capsular antigen
111
E coli strain isolated from humans with infected wounds
E. vulneris
112
E. coli strain isolated from CSF, Wounds and blood
E. hermannii
113
E. coli strain associated with diarrheal disease in children
E. albertii
114
Found in the intestinal tract of humans and animals of free living in soil, water, and on plants
Klebsiella
115
What media does klebsiella most grow?
SCA - Simmons citrate agar
KCN - Potassium Cyanide Broth
116
Plasmid transfer of antimicrobial resistance
K. pneumoniae
117
What is other name for klebsiella pneumoniae?
Friedlandler’s bacillus
118
Causes community acquired pneumonia- cough up currant jelly like sputum
Klebsiella pneumoniae
119
What is the virulence factor of klebsiella pneumoniae?
Polysaccharide capsule
120
What is the differential test for k. pneumoniae?
String test
121
What is the IMVIC reaction for k. pneumoniae?
- - ++
122
What is the TSI reaction for k. pneumoniae?
A/A, gas+, h2s -
123
Linked to Antimicrobial associated hemorrhagic colitis
K. Oxytoca
124
Causes astrophic rhinitis - a tissue destructive disease restricted to the nose (foul smelling astrophic rhinitis)
K. pneumoniae subsp ozaenae
125
Causes rhinoscleroma - an infection of the nasal cavity that manifests as an intense swelling and malformation of the entire face and neck
K. pneumoniae subsp rhicosleromatis
126
Isolated from wounds, urine, blood, and CSF
Enterobacter cloacae and E. aerogenes
127
Nationwide outbreak of septicemia resulting from contaminated IV fluids
Pantoea agglomerans
128
This specie of enterbacter Found in respiratory samples and is rarely isolated from blood cultures
Enterobacter gergoviae
129
Produces a yellow pigment and has been documented as a pathogen in neonates causing meningitis and bacteremia often coming from powdered infant formula
Cronobacter sakazakii
130
Isolated from human resources such as blood, wounds, sputum
Enterobacter hormaechei
131
Similar biochemically to e. cloacae and has been isolated from blood, urine, feces, sputum, and wounds
Enterobacter asburiae
132
What is the IMVIC reaction of enterobacter?
Neg
Neg
Pos
Pos
133
What is the TSI reaction of enterobacter?
A/A, gas+, h2s -
134
What is the color of the colony produced by serratia marcescens, s. rubidea, and s. plymuthica?
Prodigiosin or pink-red pigment
135
This specie of serratia has Musty and pungent odor or “rotten potato-like” odor
Serratia odorifera
136
This specie of serratia Ferments arabinose growth in KCN media
Serratia liquifaciens
137
Causes outbreak in nurseries, burn units and cardiac surgery units
Serratia marcescens
138
What is the IMVIC reaction for serratia?
- - ++
139
What is the tsi reaction for serratia?
K/A, gas + , h2s -
140
It is gastroenteritis and is occasionally isolated from stool culture.
Major characteristic is delayed positive citrate reaction
Hafnia alvei
141
These proteus species are widely recognized human pathogens
Proteus vulgaris and proteus mirabilis
142
Most common clinical isolate of proteus
Proteus mirabilis
143
These genus can produce swarming colonies on nonselective media
Proteus spp
144
What is the tsi reaction of proteus?
A/A
145
This specie has burnt chocolate odor
Proteus spp
146
It causes UTI and neonatal sepsis
Morganella spp
147
What is the IMVIC reaction of morganella?
++ - -
148
What is the LIA and TSI reaction for morganella?
Lia - R/A
TSI - K/A, gas+ , h2s -
149
This specie of providencia is the most commonly found in the feces of children with diarrhea
Providencia alcalifaciens
150
outbreaks in burn units; isolated from urine culture
Providencia stuartii
151
This specie of providencia documented pathogens of urinary tract ; also diarrheal disease among travelers
Providencia rettgeri
152
This specie of providencia formerly identified as a strain of P. alcalifaciens
Providencia rustigianii
153
What is the specie of edwardsiella that is only recognized human pathogen; causes bacteremia and wound infections
Edwardsiella tarda
154
What is the IMVIC reaction for edwardsiella?
++ - -
155
What is the TSI reaction of edwardsiella?
K/A , gas+ , h2s +
156
What is the IMVIC reaction of plesiomonas?
+ + - -
157
What is the tsi reaction of plesiomonas?
K/A , gas - , h2s -
158
Organisms produce GI illness in humans - not considered normal biota of the human intestinal tract
Salmonella and shigella
159
Usually indicates improper sanitary conditions and poor personal hygiene
Shigella dysentery
160
Groups within a single species of microorganisms which share distinctive surface structures
Serotype or serovar
161
Found in cold blooded animals as well as in rodents and birds
Salmonella
162
Salmonella on MAC is
Clear or colorless non-lactose fermenter
163
Role in adherence in initiating intestinal infection
Fimbriae
164
Most severe form of enteric fever
Typhoid fever
165
One of the most common forms of food poisoning
Salmonella gastroenteritis
166
What are the virulence factor of salmonella?
- fimbriae
- Enterotoxin
167
What is the Antimicrobial of choice of gastroenteritis?
- ampicillin
- chloramphenicol
168
What week does rose spots appear in typhoid fever?
2nd week
169
Who recover from infection may harbor the organisms in the gallbladder
Carrier state
170
Shigella is named after japanese microbiologist
Kiyoshi shiga
171
What is the most virulent species of shigella
Shigella dysenteriae
172
One of the causes of gay bowel syndrome
Shigella flexneri
173
Shigella serotype A
Shigella dysenteriae
174
Shigella serotype B
Shigella flexneri
175
Shigella serotype C
Shigella boydi
176
Shigella serotype D
Shigella sonnei
177
Unique in its ability to’ decarboxylate ornithine.
Produces a “delayed” positive fermentation of lactose with the formation of pink colonies on MAC
Shigella sonnei
178
What is the mode of transmission for shigella?
Direct Person to person
179
What are the three species of yersinia?
- yersinia pestis
- yersinia pseudotuberculosis
- tersinia enterolitica
180
Produced an infection that mimics appendicitis
Yersinia enterolituca
181
Causative agent of plague, a disease primarily of rodents transmitted to humans by fleas
Yersinia pestis
182
Caused sporadic cases of mesenteric lymphadenitis in humans
Yersinia pseudotuberculosis
183
What are the three forms of plague in humans?
- bubonic or glandular form
- septicemic form
- pneumonic form
184
Most common ; resukts from the bite of an infected flea
Bubonic or glandular form
185
Bacteria spread to the bloodstream
Septicemic form
186
it is referred to as the bipolar staining “safety pin” appearance
Yersinia pestis
187
What is the pattern of yersinia pestis in broth if not shaken?
Stalactite shaped
