Enterobacteriales Flashcards
Enterobacteriales
Gram (positive or negative?) _____
Motile by ___________; some are non motile
Negative rods
peritrichous flagella
Enterobacteriales
Form endospores or microcysts
T/F
F
Do not form endospores or microcysts
Enterobacteriales
Are not acid-fast.
T/F
T
Enterobacteriales
In terms of oxygen, are either ______ or _______
aerobes/facultative anaerobes
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
F. 22–35
F. Some do
T
T
An endospore is a _____,______, and _________ structure produced by certain bacteria
dormant, tough, and non-reproductive
Enterobacteriales
produce _____ and ______ during fermentation of d-glucose, other carbohydrates and polyhydroxyl alcohols.
acid and visible gas bby
Enterobacteriales
Flourishes in a salty environment
T/F
F
Not halophilic
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 _________
positive
Shigella dysenteriae; Xenorhabdus
Negative; Plesiomonas
nitrate to nitrite; Saccharobacter fermentatus
Enterobacteriaceae- family
Small or Large ?
(Homo or Hetero?) geneous group
Habitat:_______
The family includes the following genius:( ___,____,____,____,_____,____,______and others
Large
Hetero
gut of man and animals
Escherichia, Shigella, Salmonella, Enterobacter, Klebsiella, Serratia, Proteus,
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.
Escherichia coli
salmonellae and shigellae
Enterobacteriaceae- family
possess a (simple or complex?) antigenic structure
produce a variety of toxins and other virulence factors
Complex
E.coli
In terms of oxygen is __________.
Aerobic and facultatively anaerobic
E. coli
Motile or non motile?
Motile by peritrichous flagella
Ecoli is motile by ______ flagella
Motile by peritrichous flagella
E.coli
Catalase _______
Oxidase _______.
Positive
negative
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
Both acid and gas
Do not
Lower; intestine
E.coli can ferment glucose
E.coli can ferment lactose
T/F
T
T
Diseases caused by E. coli
Diarrhoea
• ___________
•__________
•______________
•____________
•________
•____________
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).
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 _______
food contamination.
O157:H7
shiga toxin-producing E. coli (STEC): AKA ______________ and _________
enterohemorrhagic E. coli (EHEC) and verocytotoxin-producing E. coli (VTEC).
Shiga-like toxin (STEC ) has been associated with __________, a severe form of diarrhea, and with ___________
hemorrhagic colitis
hemolytic uremic syndrome
Enterotoxigenic E. coli (ETEC): This strain is commonly known as a cause of ____________
Enteroaggregative E. coli (EAEC) causes __________ diarrhea.
travelers’ diarrhea.
acute and chronic
Entero_______ E. coli is an important cause of diarrhea in infants.
pathogenic
Commonest cause of UTI is???
E.coli infection
Ecoli causes sepsis
T/F
T
E. coli is one of the leading causes of meningitis
T/F
T
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
Klebsiella
(Motile or nonmotile?)
Gram-(positive or negative?)
oxidase-(positive or negative?)
____-shaped bacteria with a prominent ___________
Non motile; negative; negative
rod; polysaccharide capsule
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
Klebsiella spp. are ubiquitous in nature
T/F
T
Klebsiella spp.
are a part of the human and animal’s normal flora in the _____,_____, and _____
nose, mouth and intestine
K pneumoniae is present in the _____ and _____ of about ___% of normal individuals
respiratory tract and feces
5
Klebsiella pneumoniae subspecies _______ has been isolated from the nasal mucosa in ozena
K pneumoniae subspecies _________ form rhinoscleroma
ozaenae
rhinoscleromatis
Klebsiella _____ can cause a variety of nosocomial infections.
oxytoca
Klebsiella oxytoca may be resistant to multiple antibiotics.
T/F
T
There is evidence that K. oxytoca can cause ________ associated with antibiotic use
hemorrhagic colitis
Difference between K.oxytoca and K.pneumoniae
K.oxytoca is distinguished from K. pneumoniae based on its ability to produce indole from tryptophan
Klebsiella _________ (formerly ________________) causes a chronic genital ulcerative disease, granuloma _____,
granulomatis
Calymmatobacterium granulomatis
inguinale
Characteristics of klebsiella
Oxygen= _______
Grow well on ______ media
grow best between ____ and ___°C and at pH ____
Facultative anaerobes
Standard
35 and 37
7.2
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
Some klebsiella are motile , some are non-motile
T/F
F
all are nonmotile
Biochemical characteristics of klebsiella
ferment lactose (positive or negative?)
Indole (positive or negative?) except for K.______ and K.________
Positive
Negative ; oxytoca; ornitholytica
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.
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
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
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.
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
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.
In addition, nosocomial( hospital acquired infection) isolates are frequently resistant to numerous other antibiotics as a result of the acquisition of _______________
multidrug resistant plasmids.
Klebsiella is the ___ most common cause of UTIs
3rd
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)
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
Salmonella species
Gram-(positive or negative?)
flagellated or non-flagellated
Oxygen =—————- bacilli
Negative
Flagellated
facultatively anaerobic
The taxonomic classification of the genus Salmonella is complex and problematic.
2 species: Salmonella _____ and Salmonella _______ with many subspecies.
bongori
enterica
Characteristics of salmonella
Spore or Non spore-forming
_________ flagella
They are ____trophs
Non-spore forming
peritrichous
chemo
S. enterica subspecies are found worldwide in ______-blooded animals and in __________
S. bongori is restricted to ___-blooded animals, particularly ______
warm; the environment.
cold
reptiles
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)
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
Salmonella
Ferments _____ and ______ but not _____ and ____
glucose and mannitol
lactose and sucrose
Salmonella
does not produce gas
T/F
F
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
Salmonella is intolerant of acids in phagocytic vesicles
T/F
F
Tolerant
Salmonella Can survive in macrophages and spread from the intestine to other body sites
T/F
T
Salmonella species are _____cellular pathogens
intra
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
non typhoidal Salmonella can be invasive
T/F
T
Non typhhoidal salmonella serotype can cause paratyphoid fever
T/F
T
By being invasive
Typhoidal salmonella serotypes can only be transferred from ___________ , cause ______ infection, ______ and ______
human-to-human
food-borne
typhoid fever, and paratyphoid fever.
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
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
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
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.
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
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
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
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
There are vaccines against salmonella Typhi
T/F
T
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
Shigella is one of the leading bacterial causes of diarrhea (typically dysentery) worldwide
T/F
T
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
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
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.
SHigella ________ is considered the most virulent, and can produce a potent cytotoxin known as _____ toxin.
dysenteriae
Shiga
Shigella _______ can produce shiga toxin
Dysenteriae
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
Shigella infections are almost always limited to the ________
gastrointestinal tract
bloodstream invasion by shigella is (rare or common?)
quite rare.
Shigella
is highly communicable
the infective dose is on the order of 10^2 organisms
T/F
T
F(10^3)
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.
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
Virulence in Shigella species involves only plasmid-coded genes
F
Virulence in Shigella species involves both chromosomal-coded and plasmid-coded genes
VIRULENCE FACTORS of shigella
Endotoxin
Upon _____, all shigellae release their toxic _______. This endotoxin probably contributes to the __________
autolysis
lipopolysaccharide
irritation of the bowel wall
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.
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
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
Shigella
In the extra intestinal phase of infection by Gram-negative bacteria, _____ becomes one of the major factors that limit further growth.
iron
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
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.
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
____________ agar (SS) should be used with caution because it inhibits some strains of Shigella dysenteriae.
Salmonella – Shigella
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.
identification of individual Shigella species is often accomplished through slide ________ using absorbed _______
agglutination; rabbit antisera.
_____ and _____ testing are used to differentiate Shigella from E. coli species
PCR and ELISA
