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gram negative Flashcards

1
Q

location where klebsiella and serratia is present

A

large intestine soil and water

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2
Q

gram negative bacteria are in general which type of hemolysis? except?

A

usually non hemolytic except e coli which is beta hemolytic

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3
Q

explain the general feature of motility in gram negative bacteria, and the exception.

A

generally motile except klebsiella and shigella

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4
Q

serratia in nutrient agar has

A

red pigment

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5
Q

urease test for klebsiella and serratia

A

K: + and S: -

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6
Q

explain whether or not klebsiella and serratia is a fast or slow lactose fermenter and what kind of colonies do they form?

A

K: Fast lactose fermenter forms mucoid colonies due to capsule
S: Slow lactose fermenter = produces red-pigmented colonies

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7
Q

virulence factor of klebsiella

A

Pili for attachment
Polysaccharide capsule (mucoid)
Endotoxic and antigens

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8
Q

virulence factor of serratia

A

Non-capsulated

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9
Q

disease caused by klebsiella

A

UTI and pneumonia (makes currant-jelly
sputum with mucus and blood)
Bacteremia, necrosis, abscess formation,
antibiotic-related diarrhea (K oxytoca)

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10
Q

disease caused by serratia

A

Pneumonia (water contamination from respiratory therapy devices)
Endocarditis (injection drugs)

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11
Q

location of e coli

A

GI commensal flora

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12
Q

E coli in our GI commensal flora helps in

A

digestion, makes vitamin K2, makes biofilms
to prevent invasion of harmful bacteria like C difficile

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13
Q

fermentation of e coli

A

Ferments lactose (forms pink colonies on MacConkey) and glucose

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14
Q

virulence factors of e coli

A

Type 1 fimbriae for adhesion and siderophores: for acquiring iron for metabolism + LPS
endotoxin

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15
Q

enterohemorrhagic E.coli: what does the toxin do and clinical manifestation

A

Shiga-like toxin = inhibits 28s RRNA and 60s subunit = inhibits protein synthesis
dysentery, hemorrhagic colitis hemolytic uremic syndrome (HUS)
HUS: thrombocytopenia, hemolytic anemia and acute renal failure (Affects kidneys and blood
clotting)

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16
Q

Enteropathogenic E coli: causes and clinical manifestation

A

After attaching to brush border, enzymes flatten microvilli which reduces absorption
efflux of water = noninflammatory watery diarrhea

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17
Q

Enterotoxigenic E coli: causes and CM

A

Has fimbriae to attach to small intestine’s brush border (diarrhea).
Heat labile (CAMP-inducing) and heat stable (CGMP-inducing) toxins + water and ion release = noninflammatory diarrhea (doesn’t invade cells) also known as Traveler’s diarrhea

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18
Q

Enteroinvasive E coli: causes and CM

A

lyses phagosomes and replicates in cytoplasm with enzymes and
invades other nearby cells in the large intestine.
necrosis, inflammation = dysentery (inflammatory bloody mucus diarrhea)

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19
Q

Enteroaggregative E coli: causes and CM

A

cytotoxic production and enzymes produce mucus and biofilm
damages intestinal cells = bloody diarrhea (noninvasive)

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20
Q

Uropathogenic E coli: causes and CM

A
  • P pili attaches to urinary tract forming biofilm
    -Hemolysin is used to invade tissues and causes cystitis (inflamed bladder), pyelonephritis (inflamed kidneys) - UTI
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21
Q

what does E coli K1 do?

A

Has K1 capsular polysaccharide which binds with neuroreceptors = enters blood-brain
barrier = meningitis

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22
Q

Aside from other stereotypical patients, what is a special category of patient who are susceptible to E coli?

A

Diabetics (+ glucose in urine promotes E. coli colonization)

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23
Q

describe E coli’s resistance

A

Highly resistant to antibiotics due to bacterial conjugation

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24
Q

Pathogenic species of citrobacter

A

Citrobacter freundii, koseri and braakii

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25
location of citrobacter
Colon and environment
26
tests for citrobacter
-indole, + methyl red, -VP, +citrate (-+-+)
27
citrobacter is fast or slow lactose fermenter
slow
28
where does citrobacter colonize
CNS, oral cavity, GIT, respiratory tract
29
Disease caused by citrobacter
Sepsis, meningitis, necrotizing fasciitis (koseri), brain abscesses, UTI, respiratory tract, in bones MeN Rent BUS
30
Yersinia enterocolitica is lactose or non lactose fermenter
Non-Lactose fermenter
31
Yersinia enterocolitica fermentation
sucrose + glucose
32
Yersinia enterocolitica is oxidase positive or negative
Negative
33
Mode of transmission for Yersinia enterocolitica
GIT of domesticated animals (pigs, puppies) contaminated milk and water (fecal-oral route)
34
Virulence factors of Yersinia enterocolitica
Psychrophilic (cold): milkand water Surface proteins: adherence to GIT Yersinia outer proteins (yops): affects phagocytosis) Yersiniabactin: ironbinding protein Urease: buffers stomachacid Heat-stable enterotoxin = +CGMP = -NaCl =diarrhea (Like ETEC)
35
Patients who are susceptible to Yersinia enterocolitica
1. Liver disease 2. Hemochromatosis (iron overload) 3. Children’s with weak immunity
36
Patients who are susceptible to Y. Pestis
black death (soft tissue abscesses)
37
Disease caused by Yersinia enterocolitica
yersiniosis (GIT infection)
38
Symptoms of yersiniosis
Fever, bloody/ non-bloody diarrhea, nausea, pain in right lower quadrant (like appendicitis), soft tissue abscess
39
Campylobacter jejuni is thermophilic or halophilic
Thermophilic (42 degree)
40
Campylobacter jejuni is a lactose or non lactose fermenter
Non lactose
41
Fermentation of Campylobacter jejuni
Non-fermenting
42
Campylobacter jejuni is oxidase + or -
+ve
43
Mode of transmission of Campylobacter jejuni
Raw chicken, dirty water, raw milk (fecal-oral route)
44
Virulence factor of C jejuni
Flagellum: Invade intestinal epithelia = mucosal inflammation = bloody diarrhea
45
Patients who are susceptible to C jejuni
Long-term use of antacids, immunocompromised, people with HLA-B27 gene are more likely to develop reactive arthritis after infection due to antibodies
46
Disease caused by C jejuni
Guillaine-barre syndrome: which is a autoimmune neuropathy (paralysis)
47
Symptoms of Guillaine-barre syndrome
Very bloody diarrhea, fever, nausea, vomiting
48
Motility of Vibrio cholerae
Highly motile (darting)
49
Vibrio cholerae is thermophilic or halophilic
Halophilic
50
Vibrio cholerae are lactose or non lactose fermenters
Non lactose
51
Fermentation of Vibrio cholerae
Sucrose + glucose
52
Vibrio cholerae is oxidase + or -
+ve
53
Source of disease for Vibrio cholerae
Saltwater, contaminated water (crowded living areas) Fecal-oral route
54
Virulence factor for cholera
Cholera toxin (AB): binds with G protein to prevent GTP hydrolysis = activates adenylyl cyclase = + CAMP and + Cl = fluid moves to intestine
55
Patients who are susceptible to cholera
Immuno-compromised patients in developing countries and people who lives in crowded environment
56
Disease caused due to cholera
Watery diarrhea with mucus (20-30 times) – rice-water-like stool Which can lead to Hypovolemic shock - death
57
Symptoms of rice water stool
Nausea, abdominal pain
58
Motility of Helicobacter pylori
Very motile (many flagella)
59
(Helicobacter pylori) lactose or non lactose fermenting
Non lactose
60
Fermentation of Helicobacter pylori
Glucose
61
(Helicobacter pylori) oxidase + or -
+ve
62
Source of contamination of Helicobacter pylori
Humans (endogenous)
63
Virulence factor of Helicobacter pylori
Flagella: adherence to gastric epithelial cells Adhesins: adherence Mucinase: degrades mucous layer of stomach Urease: neutralizes stomach acid Stays under mucosal layer causing inflammation + gastrin & -somatostatin release
64
susceptibility of H pylori
Underdeveloped crowded areas Genetic predisposition
65
Disease caused by H pylori
Chronic gastritis, gastric carcinoma or MALT lymphomas, peptic ulcer disease
66
Symptoms of H pylori disease
Epigastric pain, dyspepsia, GI bleeding
67
Describe the things that are similar between Pseudomonas aeruginosa and Acinetobacter baumannii: lactose and sugar fermenting, ways the infections could be acquired.
non-lactose fermenters (colorless), doesn’t ferment sugars (pink in TSI) Wound infections and in hospitals
68
Metabolism of Pseudomonas aeruginosa
Aerobic but can grow anaerobically if nitrate is present
69
Where would you find Pseudomonas aeruginosa
Environment, human feces and throats (ubiquitous) = Grape-like odor and blue-green sheen from pyocyanin production (seen in tissue infections and sputum as well) Normally found in skin and respiratory tract (moist
70
Acinetobacter baumannii is aerobic or anaerobic
Aerobic
71
Acinetobacter baumannii is found in
Normally found in skin and respiratory tract (moist environments) – abnormal to be found in sterile places (blood)
72
Hemolysis of Pseudomonas
Beta hemolysis
73
Hemolysis of Acinetobacter
Nonhemolytic (except A hemolyticus)
74
Motility of pseudomonas and acinetobacter
PM: motile (flagella) AB: non motile (twitching fimbriae)
75
Catalase positive or negative for PM and AB
Both catalase +ve
76
Oxidase - or + for PM and AB
PM: +ve AB: -ve
77
Virulence factor of PM
LPS (endotoxins) Pili: attachment Alginate secretion (exopolysaccharide capsule): mannuronic and glucuronic acids = antiphagocytic + form biofilms (inside and also on artificial medical devices Exotoxin A (AB): catalyzes ribosylation of EF2 which inhibits protein synthesis = cell death Exoenzyme S (T3 secretion): affects cytoskeleton and signaling pathways = apoptosis Elastase: affects ECM by hydrolyzing elastin and can degrade IgA and IgG = tissue damage
78
Disease caused by PM
Respiratory (pneumonia), UTIs (catheterization) osteomyelitis, ecthyma gangrenosum – skin endocarditis - heart diarrhea, enteritis, enterocolitis - GIT conjunctivitis, keratitis – eyes
79
Disease caused by AB
Ventilator-associated pneumonia UTIs Soft tissue infections Bacteremia via IV catheters PUS B
80
People who are susceptible to PM
Patients with cystic fibrosis burn wounds low neutrophil levels immunocompromised
81
Neutropenic patients experience (PM)
Infarcts, alveolar necrosis, bacteremia, aggressive pneumonia (Can lead to respiratory failure)
82
PM community acquired infection
1. Hot tub folliculitis (infected hair follicles due to dirty water) 2. otitis externa (swelling and pain of outer ear) – can lead tocellulitis and mastoid osteomyelitis if untreated (in diabetics) 3. Osteomyelitis (S aureus also): after puncture wound (nail) /trauma to head can cause meningitis

microbiology (3 decks)

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