Gram Negative Rods I Flashcards
1
Q
Has the characteristic features of short thick rods and peritrichous flagella
A
Enterobacteriaceae
2
Q
What is the oxidase classification of enterobacteriaceae?
A
Oxidase negative
3
Q
Closely-related to enterobacteriaceae and has curved rods and polar flagella
A
Vibrio
4
Q
What is the oxidase classification of Vibrio?
A
Oxidase positive
5
Q
Curved or spiral shaped, and not closely-related to other enteric bacteria
A
Campylobacter
6
Q
The Gram negative rods are transferred by the 4 F’s, which are
A
Feces, Fingers, Flies, and Food
-Oral-fecal transmission
7
Q
What is the habitat for the gram negative rods?
A
Intestine
8
Q
Intestinal defense that kills many bacteria
A
Gastric acid
9
Q
Removes bacteria;
anti-motility drugs may prolong illness
A
Intestinal motility
10
Q
Blocks colonization
by pathogens; Antibiotics may predispose to infection
A
Normal flora
11
Q
What are the 4 cell types of the intestine?
A
Enterocytes, M cells, Macrophages, and Neutrophils
12
Q
Specializedfortranscytosisofantigens to underlying lymphoid tissue
–many pathogens ‘hitch a ride’ to exit intestine
A
M cells
13
Q
Mostly encoded by
Pathogenicity Islands, Plasmids and Phage genomes
A
Virulence factors
14
Q
Emerges when the ‘correct’ constellation of virulence factor genes appears in a clone
A
Pathogen
15
Q
For serotyping, what are the following antigens?
- ) H
- ) O
- ) K
A
- ) Flagella
- ) LPS
- ) Kapsule
16
Q
Different serological types
(serotypes or serovars)
differ in
A
Virulence
17
Q
Serotyping is useful for
A
Epidemiology
18
Q
What are the three types of intestinal infections?
A
- ) Non-inflammatory
- ) Inflammatory
- ) Penetrating
19
Q
Bacteria in lumen
A
Non-inflammatory
20
Q
Bacteria invade wall
A
Inflammatory
21
Q
Bacteria get beyond intestinal wall
A
Penetrating
22
Q
Watery diarrhea; no wbc (or lactoferrin) in feces; no fever
A
Non-inflammatory enteritis
23
Q
What are two virulence factors for non-inflammatory enteritis
A
Adhesins and exotoxins
24
Q
Toxin deliberately secreted against endotoxin
A
Exotoxins
25
Exotoxins stimulate
Salt transport
26
Toxin-producing E. Coil that can cause non-inflammatory enteritis
Vibrio Cholerae
27
There is a vibrio cholerae endemic in
SE Asian
28
The first 6 pandemics of Vibrio cholerae were caused by strains of serotyping
O1
29
The classic O1 biotype is replaced by
El Tor
30
In the 7th vibrio cholerae pandemic, the classic O1 biotype was replaced by
O139
31
Non-pathogenic strains of Vibrio cholerae are common world-wide in
Salt/brackish water
32
Causes massive diarrhea:
-up to 20 liters stool per day
Vibrio Cholerae disease
33
What are the treatments for Vibrio cholerae disease?
Fluid replacement and anti-biotics (tetracycline or ampicillin)
34
What type of agars can we use to culture Vibrio cholerae
Blood, chocolate, MacConkey, and TCBS agar
35
Adds ADP-ribose group to Gs protein
A subunit of Cholera toxin
36
Permanently activates Gs which stimulates adenyl cyclase
Cholera toxin
37
High cAMP causes high
Cl- transport
38
The transporter for these Cl- ions is
CFTR
39
High salt concentration in intestinal lumen produces
Osmotic inflow of water
40
The virulence of Vibrio cholerae is from a toxin coregulated
Pilus (type IV pilus)
41
Common in natural waters worldwide
-The reason we can get diarrhea from eating raw fish & shellfish
Non-cholera Vibrios
42
Require NaCl for culture, meaning they are halophiles
Non-cholera Vibrios
43
What type of medium do non-inflammatory Vibrios grow on?
Thiosulfate-Citrate-Bile Salts (TCBS)
44
What are the three types of E. coli that cause diarrhea?
Enterotoxigenic E. coli [ETEC], Enteropathogenic E. coli [EPEC], Shiga toxin producing E. coli [STEC]
45
Most adults are immune to
-not immune elsewhere
Local ETEC
46
The most common cause of "Traveler's diarrhea"
ETEC
47
There are two exotoxins of ETEC that are distinguished by heat sensitivity. What are they?
Labile Toxin (LT) and Stable Toxin (ST)
48
Resembles cholera toxin, but is produced in lower amounts
Labile Toxin (LT)
49
Structural analogue of gut peptide hormone, and stimulates a guanyl cyclase-coupled receptor
Stable Toxin (ST)
50
Elevated cAMP or cGMP produces diarrhea as in
-Less toxin, less severe disease
Cholera
51
ETEC can cause
-Diarrhea, often bloody, with WBC in feces
Inflammatory Enteritis
52
Bacteria invade and kill enterocytes: induce their own phagocytosis via Type III system in
Inflammatory Enteritis
53
In inflammatory enteritis, we see diarrhea from local production of inflammatory mediators by
Enterocytes and Neutrophils
54
What are three types of ETECs?
Shigella, Salmonella, invasive E. coli, and Campylobacter
55
Have a type III secretion system exports proteins to cytosol, causing cytoskeletal rearrangement
Enteropathogenic E. coli (EPEC)
56
Adhere to the surface of enterocytes
EPECs
57
With EPEC infection, we see the disappearance of the
Brush border
58
Also with EPEC infection, we see the production of a pedestal that cups the
Bacterium
59
EPECs have filaments protruding from the bacteria. This is the
Type III secretion system
60
Only infects humans and has a very low infectious dose
-Genetically virtually identical to E. coli
Shigella
61
Frequent, painful, low-volume stools containing blood, wbc, mucus; abdominal cramps
Bacillary dysentery from Shigella
62
There are 4 species of Shigella which are defined by an O-antigen. What are they?
S. dysenteriae, S. flexneri, S. boydii, and S. sonnei
63
The most virulent and least common form of Shigella
S. dysenteriae
64
The least virulent and most common form of Shigella
S. sonnei
65
Invade and kill cells of the intestinal mucosa
-Transcytosed by M cells
Shigellae
66
Shigellae invade enterocytes via basolateral surface & induce phagocytosis by
Type III system
67
Lyse the phagocytic vacuole so that bacteria can enter the cytosol
Shigellae
68
Proteins on the surface of Shigellae induce
Actin polymerization
69
This "actin tail" then pushes bacteria through the plasma membrane into
Adjacent cells
70
A subunit cleaves RNA of large ribosomal subunit at specific position
-AB5 structure
Shiga toxin
71
Ribosome inactive bacteria
Shiga toxin
72
Shiga isolates, without toxin, produce a less severe form of
Dysentery
73
A major role of shiga toxin is in?
-Microvascular damage in the kidney. Red cell lysis
Hemolytic-Uremic Syndrome (HUS)
74
EPEC that produce Shiga-like toxin (SLT)
Shiga toxin producing E. coli (STEC)
75
Also referred to as Enterohemorrhagic E. coli (EHEC) when they cause HC
STEC
76
The shiga toxin is classified as a
Verotoxin
77
What is the predominant serotype of STEC?
O157:H7
78
One identification characteristic of STEC is that it is
Sorbitol negative
79
Principal host of O157:H7 is
Cattle
80
Named for pathologist Daniel Salmon, not the fish
-Infections with rare serological types acquired from pet reptiles
Non-typhoidal Salmonella
81
Exit lumen via M cells, invade enterocytes, multiply locally
-Causes gastroenteritis (enterocolitis)
Non-typhoidal Salmonella Disease
82
Induce apoptosis in macrophages via Type III system
Non-typhoidal Salmonella
83
What are some of the characteristics of Non-typhoid Salmonella disease?
Non-bloody diarrhea, fever, nausea, and vomiting
84
Characterized by a “Gullwing” morphology on gram stain
Campylobacter Jejuni
85
Campylobacter jejuni is associated witgh
Guillian Barre Syndrome
86
Common, not recognized until recently, transmitted from contaminated food (chicken)
Campylobacter jejuni
87
What is the selective medium used for Campylobacter jejuni recovery?
Campy-BAP
88
Associated with peptic ulcers and MALT lymphoma
H. Pylori
89
40-80 % of adults are colonized with this bacteria that causes chronic infection of the gastric mucosa
Heliobacter pylori
90
Resides below the mucus layer, so it escapes stomach acid
H. Pylori
91
The pathogenic strains of H. pylori have what type of secretion system to export cytotoxin?
Type IV secretion
92
Enzyme in H. pylori that converts urea to ammonia
Urease
93
H. pylori is diagnosed by the
Breath test
94
Treated with antibiotics + bismuth salt [Pepto-bismol] + proton pump inhibitor to reduce gastric acid, speed healing
H. Pylori
95
When penetrating bacteria is in the small intestine, we see
Diarrhea
96
Later, when penetrating bacteria has invaded/exited the large intestine, we can see
Systemic Febrile illness
97
Adhesins, cell invasion, and the inhibition/killing of phagocytes are all virulence factors of
Penetrating disease
98
Bacteria that travels from the intestine to the local lymph nodes
Yersinia
99
Has a type III system translocates proteins that inhibit phagocytosis
Yersinia
100
Painful inflammation of lymph nodes, may mimic appendicitis with
Yersinia infection
