Enterobacteriales Flashcards

1
Q

Enterobacteriales

Gram (positive or negative?) _____

Motile by ___________; some are non motile

A

Negative rods

peritrichous flagella

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2
Q

Enterobacteriales

Form endospores or microcysts

T/F

A

F

Do not form endospores or microcysts

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3
Q

Enterobacteriales

Are not acid-fast.

T/F

A

T

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4
Q

Enterobacteriales

In terms of oxygen, are either ______ or _______

A

aerobes/facultative anaerobes

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5
Q

Enterobacteriales

grow well on standard lab media at 19-22
None grow on D glucose as the sole source of carbon
some require vitamins and/ or amino acids.
Have both oxidative and fermentative metabolism

T/F

A

F. 22–35
F. Some do
T
T

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6
Q

An endospore is a _____,______, and _________ structure produced by certain bacteria

A

dormant, tough, and non-reproductive

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7
Q

Enterobacteriales

produce _____ and ______ during fermentation of d-glucose, other carbohydrates and polyhydroxyl alcohols.

A

acid and visible gas bby

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8
Q

Enterobacteriales

Flourishes in a salty environment

T/F

A

F

Not halophilic

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9
Q

Enterobacteriales

Most are catalase-(positive or negative?) , except for __________ O group 1 and _______.

Most are oxidase (positive or negative?) , except for ________.

Most reduce _____ to _____, except _________

A

positive

Shigella dysenteriae; Xenorhabdus

Negative; Plesiomonas

nitrate to nitrite; Saccharobacter fermentatus

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10
Q

Enterobacteriaceae- family

Small or Large ?
(Homo or Hetero?) geneous group
Habitat:_______

The family includes the following genius:( ___,____,____,____,_____,____,______and others

A

Large
Hetero

gut of man and animals

Escherichia, Shigella, Salmonella, Enterobacter, Klebsiella, Serratia, Proteus,

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11
Q

Enterobacteriaceae- family

Some such as _________, are part of the normal microbiota and incidentally cause disease

others e.g. the ___ and ______ , are regularly pathogenic for humans.

A

Escherichia coli

salmonellae and shigellae

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12
Q

Enterobacteriaceae- family

possess a (simple or complex?) antigenic structure
produce a variety of toxins and other virulence factors

A

Complex

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13
Q

E.coli

In terms of oxygen is __________.

A

Aerobic and facultatively anaerobic

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14
Q

E. coli

Motile or non motile?

A

Motile by peritrichous flagella

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15
Q

Ecoli is motile by ______ flagella

A

Motile by peritrichous flagella

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16
Q

E.coli

Catalase _______
Oxidase _______.

A

Positive

negative

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17
Q

Ecoli
______________ are formed from most fermentable carbohydrates

When Lactose is fermented, it Usually (do or do not ?) produce H2S.

Occur naturally in the (upper or lower?) part of the ______ of warm-blooded animals

A

Both acid and gas

Do not

Lower; intestine

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18
Q

E.coli can ferment glucose
E.coli can ferment lactose

T/F

A

T
T

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19
Q

Diseases caused by E. coli

Diarrhoea

• ___________
•__________

•______________
•____________
•________
•____________

A

shiga toxin-producing E. coli (STEC)

Enterotoxigenic E. coli (ETEC)

Enteroaggregative E. coli (EAEC)

Enteroinvasive E. coli (EIEC).

Enteropathogenic E. coli (EPEC)

Diffusely adherent E. coli (DAEC).

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20
Q

Diseases caused by E. coli
Diarrhoea
• Shiga toxin-producing E. coli (STEC): This is the bacteria most commonly known for E. coli _______________

E.g E. coli _______

A

food contamination.

O157:H7

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21
Q

shiga toxin-producing E. coli (STEC): AKA ______________ and _________

A

enterohemorrhagic E. coli (EHEC) and verocytotoxin-producing E. coli (VTEC).

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22
Q

Shiga-like toxin (STEC ) has been associated with __________, a severe form of diarrhea, and with ___________

A

hemorrhagic colitis

hemolytic uremic syndrome

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23
Q

Enterotoxigenic E. coli (ETEC): This strain is commonly known as a cause of ____________

Enteroaggregative E. coli (EAEC) causes __________ diarrhea.

A

travelers’ diarrhea.

acute and chronic

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24
Q

Entero_______ E. coli is an important cause of diarrhea in infants.

A

pathogenic

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25
Commonest cause of UTI is???
E.coli infection
26
Ecoli causes sepsis T/F
T
27
E. coli is one of the leading causes of meningitis T/F
T
28
Diagnosis of E.coli Media: grows well on standard laboratory medium but _____ agar or ____ is usually used to demonstrate lactose fermentation ________ may be used for identification and resistance testing
MacConkey; EMB Chromagar
29
Klebsiella (Motile or nonmotile?) Gram-(positive or negative?) oxidase-(positive or negative?) ____-shaped bacteria with a prominent ___________
Non motile; negative; negative rod; polysaccharide capsule
30
Named after German-Swiss microbiologist _____— (1834–1913). ___________ described Klebsiella bacillus which is why it was termed __________ for many years
Edwin Klebs Carl Friedlander Friedlander bacillus
31
Klebsiella spp. are ubiquitous in nature T/F
T
32
Klebsiella spp. are a part of the human and animal's normal flora in the _____,_____, and _____
nose, mouth and intestine
33
K pneumoniae is present in the _____ and _____ of about ___% of normal individuals
respiratory tract and feces 5
34
Klebsiella pneumoniae subspecies _______ has been isolated from the nasal mucosa in ozena K pneumoniae subspecies _________ form rhinoscleroma
ozaenae rhinoscleromatis
35
Klebsiella _____ can cause a variety of nosocomial infections.
oxytoca
36
Klebsiella oxytoca may be resistant to multiple antibiotics. T/F
T
37
There is evidence that K. oxytoca can cause ________ associated with antibiotic use
hemorrhagic colitis
38
Difference between K.oxytoca and K.pneumoniae
K.oxytoca is distinguished from K. pneumoniae based on its ability to produce indole from tryptophan
39
Klebsiella _________ (formerly ________________) causes a chronic genital ulcerative disease, granuloma _____,
granulomatis Calymmatobacterium granulomatis inguinale
40
Characteristics of klebsiella Oxygen= _______ Grow well on ______ media grow best between ____ and ___°C and at pH ____
Facultative anaerobes Standard 35 and 37 7.2
41
Characteristics of Klebsiella most produce _______ colonies on plates because of the production of a luxuriant __________ or ________ , which can be used for serologic identification
highly mucoid polysaccharide capsule or slime layer
42
Some klebsiella are motile , some are non-motile T/F
F all are nonmotile
43
Biochemical characteristics of klebsiella ferment lactose (positive or negative?) Indole (positive or negative?) except for K.______ and K.________
Positive Negative ; oxytoca; ornitholytica
44
Virulence factors of klebsiella Polysaccharide capsule: The principal virulence factor that has been described for K. pneumoniae is its polysaccharide capsule, which consisits of repeating subunits of ____________ and, very often, _________ (as negatively charged components) more than _____ antigenic varieties and is responsible for its mucoid colony phenotype. Some capsule types, such as ____ and ____, may be more important than others. The mechanism by which capsule promotes virulence is believed to be due to ____________ Animal models have revealed a role for the capsule in infection of the ______ and ______
four to six sugars uronic acids 70 K1 and K2 inhibition of phagocytosis urinary tract and pneumonia.
45
Virulence factors of klebsiella •Adhesins -K. pneumoniae can produce a variety of ______ types, including ______ that are involved in adherence to host cells. •______ resistance Pathogenic strains are able to resist ______ •LPS -an endotoxin -important in the pathology of _______
fimbrial; type 1 pili Serum ; complement proteins septicemia
46
Virulence factors of klebsiella Siderophores •are (low or high?) -molecular-weight ________ that are capable of ___________________
Low; iron chelators competitively taking up iron bound to host proteins
47
Iron is an essential factor in bacterial growth T/F
T functioning mainly as a redox catalyst in proteins participating in oxygen and electron transport processes.
48
enterobacteria synthesize a variety of siderophores, which belong to two different chemical groups, one consisting of the ______-type siderophores and one consisting of the ____-type siderophores.
phenolate hydroxamate
49
All strains of K. pneumoniae are resistant to ______ as a result of the presence of a chromosomal gene encoding a ______________
ampicillin penicillin-specific β- lactamase.
50
In addition, nosocomial( hospital acquired infection) isolates are frequently resistant to numerous other antibiotics as a result of the acquisition of _______________
multidrug resistant plasmids.
51
Klebsiella is the ___ most common cause of UTIs
3rd
52
Klebsiella pneumoniae is a primary pathogen capable of causing ______,____,______ in otherwise healthy people. Causes ______________ and occurs in those who are debilitated by various underlying conditions.
UTIs, liver abscess, and pneumonia healthcare associated infections(HCAIs)
53
HCAIs caused by K. pneumoniae include ___ infections, ______ infections and other invasive devices, _____ infections, peritonitis, and _____; in addition to UTIs, liver abscess, and pneumonia
wound blood stream biliary tract meningitis
54
Salmonella species Gram-(positive or negative?) flagellated or non-flagellated Oxygen =—————- bacilli
Negative Flagellated facultatively anaerobic
55
The taxonomic classification of the genus Salmonella is complex and problematic. 2 species: Salmonella _____ and Salmonella _______ with many subspecies.
bongori enterica
56
Characteristics of salmonella Spore or Non spore-forming _________ flagella They are ____trophs
Non-spore forming peritrichous chemo
57
S. enterica subspecies are found worldwide in ______-blooded animals and in __________ S. bongori is restricted to ___-blooded animals, particularly ______
warm; the environment. cold reptiles
58
Biology, Virulence, and Disease of salmonella Is a fermenter? oxidase (positive or negative?) Lipopolysaccharide consists of __________, core _____ (______), and ____(_____)
Yes Negative outer somatic O polysaccharide polysaccharide; common antigen lipid A (endotoxin)
59
Biochemical of salmonella Indole( positive or negative?) Methyl red (positive or negative?) VP (positive or negative?) Citrate (positive or negative?) S typhi (positive or negative?) Hydrogen sulphide usually(positive or negative?)
Negative Positive Negative ; negative Positive positive
60
Salmonella Ferments _____ and ______ but not _____ and ____
glucose and mannitol lactose and sucrose
61
Salmonella does not produce gas T/F
F
62
Subspecies of salmonella Salmonella enterica serova ___ Salmonella serova _______ Salmonella enterica serova _____ in humans Salmonella enterica serova choleraesuis in ____ Salmonella enterica serova ______ in humans
typhi paratyphi typhimurium pigs enteritidis
63
Salmonella is intolerant of acids in phagocytic vesicles T/F
F Tolerant
64
Salmonella Can survive in macrophages and spread from the intestine to other body sites T/F
T
65
Salmonella species are _____cellular pathogens
intra
66
Non typhoidal salmonella serotypes -can be transferred from _________ and from _________ - they usually invade only the ______ and cause ________
animal-to-human human-to-human gastrointestinal tract; salmonellosis
67
non typhoidal Salmonella can be invasive T/F
T
68
Non typhhoidal salmonella serotype can cause paratyphoid fever T/F
T By being invasive
69
Typhoidal salmonella serotypes can only be transferred from ___________ , cause ______ infection, ______ and ______
human-to-human food-borne typhoid fever, and paratyphoid fever.
70
Typhoid fever is caused by _________________- (the typhoidal form), or in addition spreads throughout the body, invades organs, and secretes ______ (the ____ form). can lead to life-threatening ______ shock and ____ shock
Salmonella invading the bloodstream endotoxins; septic hypovolemic; septic
71
Mechanism of infection of salmonella Non typhoidal serotypes preferentially enter _____ on the intestinal wall by _______________, a process associated with intestinal ________ and ______. They disrupt _____between the cells of the intestinal wall, impairing the cells' ability to _________________________ into and out of the intestine
M cells bacterial-mediated endocytosis inflammation and diarrhoea. tight junctions ; stop the flow of ions, water, and immune cells
72
In non typhoidal salmonella serotypes, The combination of the inflammation caused by bacterial-mediated endocytosis and the disruption of tight junctions is thought to contribute significantly to the induction of ________.
diarrhoea
73
Mechanism of infection of salmonella Pathogenic salmonellae ingested in food survive passage through the _____ barrier invade the mucosa of the small and large intestine and ________. Invasion of epithelial cells stimulates the release of _______ which induce an ______. The acute inflammatory response causes _____ and may lead to _____ and destruction of the mucosa. The bacteria can disseminate from the intestines to cause _________
gastric acid produce toxins proinflammatory cytokines ; inflammatory reaction diarrhea; ulceration; systemic disease.
74
Epidemiology of salmonella Most infections are acquired by ___________________________ are the most common sources of infection) ________________ spread in children
eating contaminated food products (poultry, eggs, and dairy products Direct fecal-oral
75
Salmonella ____ and Salmonella ______ are strict human pathogens (no other reservoirs); these infections are passed person to person (Symptomatic or Asymptomatic?) (short or long?) -term colonization occurs commonly
Typhi; Paratyphi asymptomatic; long
76
Individuals at risk for infection of salmonella include those who eat _____________ poultry or eggs patients with ___________ levels, and immunocompromised patients Infections occur worldwide, particularly in the ____ months of the year
improperly cooked reduced gastric acid warm
77
Treatment, Prevention, and Control of salmonella Antibiotic treatment not recommended for _______ T/F With reason
enteritis T because this may prolong the duration of disease
78
There are vaccines against salmonella Typhi T/F
T
79
Shigella app Named after ______, who first discovered it in 1897 ______pathogenic microorganism The causative agent of _____ causes disease in _____, but not in other mammals. only naturally found in _____ and _____
Kiyoshi Shiga food borne shigellosis primates humans and gorillas
80
Shigella is one of the leading bacterial causes of diarrhea (typically dysentery) worldwide T/F
T
81
Shigella species are classified into 4 serogroups Serogroup A: S.______ (15 serotypes) Serogroup B: S. _____ (six serotypes) Serogroup C: S._______ (19 serotypes) Serogroup D: S.______ (one serotype)
dysenteriae flexneri boydii sonnei
82
MORPHOLOGY AND CHARACTERISTICS of shigella _______ forms occur in young cultures (Motile or non-motile ?) Encapsulated or Non-Encapsulated Spore forming or Non spore-forming
Coccobacillary Non-motile Non-encapsulated Non-spore forming
83
Characteristics of shigella Does or does not ferment lactose? form acid or does not form acid from carbohydrates
do not ferment lactose, or do so slowly. form acid from carbohydrates but rarely produce gas.
84
SHigella ________ is considered the most virulent, and can produce a potent cytotoxin known as _____ toxin.
dysenteriae Shiga
85
Shigella _______ can produce shiga toxin
Dysenteriae
86
MODE OF TRANSMISSION of shigella spl _______ route transmission is typically through one of three mechanisms: 1)_____ of ______ 2)_______ of _____ 3)by ________ by ______ Spread of infection linked to ___ has also been recorded.
Fecal-oral ingestion of contaminated foods drinking of contaminated water person-to-person contact by anal sexual contact. flies
87
Shigella infections are almost always limited to the ________
gastrointestinal tract
88
bloodstream invasion by shigella is (rare or common?)
quite rare.
89
Shigella is highly communicable the infective dose is on the order of 10^2 organisms T/F
T F(10^3)
90
Pathogenesis of shigella Invasion of _______ cells (eg, M cells) by induced ______, then ____ from the _____, multiplication and spread within the _________, and ________
mucosal epithelial phagocytosis escape; phagocytic vacuole; epithelial cell cytoplasm; passage to adjacent cells.
91
Pathogenesis of shigella ______ in the wall of the large intestine and terminal ileum lead to ______ of the mucous membrane, superficial ______, bleeding, and formation of a“ _______ ” on the ulcerated area , which consists of fibrin, leukocytes, cell debris, a necrotic mucous membrane, and bacteria. As the process subsides, _______ fills the ulcers, and _______ forms
Microabscesses; necrosis ulceration; pseudomembrane granulation tissue scar tissue
92
Virulence in Shigella species involves only plasmid-coded genes
F Virulence in Shigella species involves both chromosomal-coded and plasmid-coded genes
93
VIRULENCE FACTORS of shigella Endotoxin Upon _____, all shigellae release their toxic _______. This endotoxin probably contributes to the __________
autolysis lipopolysaccharide irritation of the bowel wall
94
VIRULENCE FACTORS of shigella •Shigella Dysenteriae Exotoxin S dysenteriae type __ (Shiga bacillus) produces a heat- _____ exotoxin that affects both the ______ and ______
1; labile gut and the central nervous system.
95
Shigella Dysenteriae Exotoxin The exotoxin is a protein that is antigenic as an enterotoxin, it produces _____, inhibits ______ and ——— absorption in the small intestine. as a “neurotoxin,” may contribute to the ______ and _______ of S dysenteriae infections and to the central nervous system reactions observed in them ( ______,______ ).
diarrhea; sugar and amino acid extreme severity and fatal nature meningismus, coma
96
VIRULENCE FACTORS of shigella Plasmids: Gene for synthesis of polypeptides that cause _____ is encoded on a large (220kb) plasmid. Siderophores, a group of ____-coded genes, control the _________________________. Enterotoxin : _______ (___)
cytotoxicity plasmid acquisition of iron from host cells from its protein-bound state Shigatoxin; Stx
97
Shigella In the extra intestinal phase of infection by Gram-negative bacteria, _____ becomes one of the major factors that limit further growth.
iron
98
LABORATORY IDENTIFICATION of shigella Specimens Faeces/rectal swab •Faeces should be collected in an appropriate sterile container, transported to the laboratory as soon as possible (if longer than __h keep at __oC), may be stored at __oC for 24 hours before culture. •Rectal swabs put into a ___ transport medium containing modified ____ medium, transported to the laboratory as soon as possible. May be stored at ____ temperature for 24 hours before culture.
2; 4 4 tube; Stuart’s room
99
Culture for Shigella species Shigella is a (fastidious or non-fastidious?) organism Because of the nature of the specimens for culture, Shigella detection is still highly dependent on employing appropriate _______
non-fastidious culture media.
100
For optimal isolation of Shigella, two different selective media should be used. A ____ – purpose plating medium of (low or high?) selectivity (e.g., __________ ) and A more selective agar medium (e.g. ____________).
general Low MacConkey-MAC xylose lysine desoxycholate agar-XLD
101
____________ agar (SS) should be used with caution because it inhibits some strains of Shigella dysenteriae.
Salmonella – Shigella
102
There is a reliable effective enrichment medium for all types of Shigella T/F If T, mention it If F, what is now used
F There is no reliable effective enrichment medium for all types of Shigella, but Gram-negative (GN) broth and Selenite broth are frequently used.
103
identification of individual Shigella species is often accomplished through slide ________ using absorbed _______
agglutination; rabbit antisera.
104
_____ and _____ testing are used to differentiate Shigella from E. coli species
PCR and ELISA