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Flashcards in Gram Negative Bacteria Deck (82):
1

Describe the structure of a G- bacteria.

It has an inner membrane with proteins, a periplasm with lipoproteins and a peptidoglycan cell wall, and an outer membrane with proteins, LPS and porins

2

What are the four components of LPS from out to in?

1. O-antigen made of repeating sugars
2. Outer core with heptose, glucose, galactose
3. Inner core with heptose and KDO
4. Lipid A which confers virulence

3

Gram negative rods can be divided into two major groups. What are they?

Fermenters and non-fermenters

4

Are enterobacteriacae fermenters or non-fermenters? What strains of bacteria fall in this category?

They are gram negative rods that are fermenters.
Enterobacteriacae are vibrio and aeromonas

5

What bacteria are gram negative rod fermenters that are lactose fermenters? Which are fast and which are slow?

1. E. coli- fast
2. Klebsiella-fast
3. Enterobacter-fast
4. citrobacter-slow
5. serratia-slow

6

What are gram negative fermenters that cannot ferment lactose? (only other sugars)

Salmonella
shigella
proteus
yersinia

7

Which gram negative rods are non-fermenters?

1. pseudomonas aeruginosa
2. acinetobacter
3. Xanthomanas
4. Strenotrophomonas
5. Burkholderia
6. Helicobacter
7. Campylobacter

8

What are examples of gram negative cocci that ferment maltose and glucose?

Niesseria menigitidis

9

What are examples of gram negative cocci that do not ferment maltose, but can ferment glucose?

Niesseria gonorrheae

10

Gram negative cocci are all strongly ______ positive.

oxidase

11

Gram negative coccobacillary _____________ oxidase positive.

+/-

12

What are examples of coccobacillary gram negatives?

1. Haemophilus influenza- cofactors
2. Bordatella pertussis- special media
3. moraxella catarrhalis
4. brucella abortus
5. pasteurella multocida

13

Lactose fermenting ____________ can be differentiated from non-lactose fermenting ________________.

Lactose= E. coli
Non-lactose = Salmonella

14

What agar would be used to isolate gram negative bacteria?

MacConkey's because crystal violet and bile restrict the growth of gram positives

15

What agar is used to isolate gram positives?

Colistin (nalidixic acid) because it binds LPS to inhibit growth of gram negatives

16

Describe the oxidase test.

It is used to see if a bacteria can produce cytochrome c oxidase (showing it uses an electron transport chain -- aerobic)
If something is oxidase positive, it will convert colorless solution to purple

17

Describe Enterobacteriaceae:
1. gram stain and shape
2. oxygen usage
3. spore capability
4. catalase + or -
5. Fermentation ability
6. motility/type of flagella

1. Gram negative rod
2. facultative anaerobe
3. can NOT form spores
4. Catalase +
5. ferments glucose and others
6. motile with peritrichous flagella

18

What is the most common enterobacteriaceae?

E. coli

19

Where is the reservoir for E. coli?

GI tract and they are commensal

20

What are the three most common syndromes associated with E. coli?

1. Diarrhea
2. UTI
3. neonatal sepsis and meningitis

21

What is the number one cause of UTI?

E. coli

22

What pili are associated with the attachment of E. coli?

1. Type 1 pillin
2. P fimbrae

23

For E. coli, certain ____ and _____ antigens correlate to disease

O (LPS) and K (capsular)

24

What antigen of E. coli is responsible for the vast majority of neonatal sepsis?

K1 capsular antigen

25

The KI capsular antigen of E. coli resembles the structure of ___________________________ because of the sailic acid.

group B streptcoccus capsule

26

What are the three major toxins associated with diarrheal syndromes of E. coli?

1. Heat-labile toxin (plasmid)
2. Heat-stable toxin (plasmid)
3. Shiga-like toxin (lysogenic prophage)

27

Describe the heat-labile toxin of E. coli. What does it cause?

It is an A-B toxin (like cholera) that activates adenylate cyclase.
It causes traveler's diarrhea

28

Describe the heat-stable toxin of E. coli What does it cause?

It is an AB toxin that activates guanylate cyclase and causes diarrhea

29

Describe the shiga-like toxin of E. coli.
What is the major example?

It is a lysogenic prophage that acts as an enterotoxin causing fluid secretion

Prime example: O157:H7

30

Describe Vibrio spp:
1. gram stain
2. motility (what kind of flagella)

1. They are curved gram negative rods
2. sIngle Polar flagella

31

What is the habitat of Vibrio spp?

Aqueous environments

(oceans, brackish water, eating shellfish, fecal-oral spread)

32

What are the three most notable kinds of vibrio spp?

1. Vibrio cholera
2. Vibrio parahaemolyticus
3. Vibrio vulinficus

33

What type of toxin is associated with vibrio cholera?

AB toxin that is a lysogenic prophage. It increases cAMP in the host causing secretory diarrhea (20L/day--> dehydration/death)

34

What serotypes of O antigen are associated with vibrio cholera?

O1 and O139

35

What disease is caused by vibrio parahaemolyticus?

gastroenteritis- cramping, abdominal pain, nausea, vomiting, fever, bloody diarrhea

36

What disease is associated with vibrio vulnificus? How do you acquire this infection?

1.Soft tissue infection and sepsis
2. liver disease

You get V. vulnificus from eating raw oysters

37

Describe Helicobacter pylori:
1. gram stain and shape
2. oxygen consumption

They are gram negative rods with a curved shape.
They are motile
Microaerophiles

38

What do helicobacter pylori utilize for energy?

Amino acids.
they utilize a urease to break urea into ammonium and carbon dioxide

39

Where do helicobacter pylori reside?

In the stomach and duodenum

40

What disease do helicobacter pylori cause?

Peptic ulcers that can lead to:
Malignant carcinoma
MALT lymphoma (cured by antibiotics)

41

What is unique about the growth of C. jejuni and other campylobacter?

They grow best at 42 degrees celcius

42

Describe the shape, gram stain and motility of Campylobacter.

They are GNR that are curved and motile

43

What is the reservoir for campylobacter?

Birds

44

What bacteria contaminates most chickens in the US?

Campylobacter

45

What disease presentation is associated with campylobacter?

Febrile, bloody diarrhea

46

Describe Pseudomonas aeruginosa:
1. gram stain and shape
2. Motility
3. oxygen consumption

1. GNR
2. motile with polar flagella
3. aerobic- (non-fermentor, oxidase +)

47

Pseudomonas aeroginosa is an aerobic GNR. This means that is will test ________ positive and will be a ______________.

It will test oxidase positive and will be a non-fermentor

48

What is unique about the growth of pseudomonas aeroginosa?

It has a fruity smell in culture and has pigments:
Pyocyanin and pyoverdin

49

What is the reservoir for pseudomonas aeruginosa?

Soil and water organisms (ubiquitous)

50

What virulence factor is associated with pseudomonas aeruginosa?

It can form biofilm

51

What diseases are associated with pseudomonas aeruginosa?

1. Nosocomial pneumonia associated with ventilators
2. Burn patients
3. cystic fibrosis

52

What is the gram stain and shape of pasteurella mutlocida?

It is a gram negative coccobacillary that is small and non-motile

53

What is the reservoir of pasteurella mutlocida?

It lives in the mouths of cats and dogs so it can cause infection after a bite

54

Describe the gram staining and shape of francisella?

GNR that is small and non-motile

55

What region of the country has francisella?

Tulare county in CA is where it was found, but it is now seen most in the midwest (oklahoma especially)

56

What disease is associated with francisella?
How is the infection acquired?

It is a zoonotic infection that causes "rabbit fever" and is acquired via puncture through skin or inhalation

57

What is the gram staining and oxygen consumption of legionella pneumophila?

It is a GNR that is aerobic and requires fastidious nutrition on culture

58

What is the reservoir for legionella?

It is ubiquitous in water and has adapted to parasitize free living amoeba

59

What specific cell is legionella an intracellular pathogen to?

Macrophages where they inhibit phagolysosomal fusion, acidification and respiratory burst

60

What disease is caused by legionella infection?

Community acquired pneumonia

61

Describe Neisseria:
1. gram staining
2. shape
3. oxygen consumption
4. fastidious growth

1. GN cocci
2. diplococci
3. aerobic- (oxidase +, non-fermentor)
4. requires excess CO2 to grow in lab

62

What agar would you use to grow Neisseria gonorrhea and Neisseria meningitidis?

Chocolate agar- blood agar that has been heated to release internal contents of RBC

Thayer-Martin from nonsterile sites

63

What is the reservoir of N. meningitidis?

nasopharynx of humans

64

What is the most common cause of sporadic bacterial meningitis in young adults (20-30)?

N. meningitidis

65

Where are epidemics of N. meningitidis likely to occur?

Highly crowded areas like dorms, prisons, military barracks

66

What is the main virulence factor of N. menigitidis?

It has a capsule to allow it to be antiphagocytic

67

How many serotypes does the N. meningitidis capsule have? What serotypes cause disease?

Which serotypes are there vaccines for?

There are 13 serotypes and A B C Y and W135 cause disease

There are vaccines for A C Y and W135 (NOT B)

68

What is the reservoir for N. gonorrhea?

humans- common STD

69

What are the 2 virulence factors associated with N. gonorrhea?

1. Pilin for attachment (with phase variation)
2. IgA protease to avoid immune detection

70

How do neisseria (both gonorrhea and meningitidis) avoid immune detection?

They have IgA protease

71

What is the most common presentation of N. gonorrhea?

1. Urethritis- drip/clap where there is milky white discharge and burning dysuria

2. prostatitis and orchitis in men
3. cervicictis and salpingitis (PID) in women

72

If gonorrhea disseminates beyond genitalia, what can it cause?

Dermatitis-arthritis syndrome

73

There are many other Neisseria besides gonorrhea and meningitidis.
They are all __________ positive
They differ in what four ways?

They are all oxidase positive
They differ in :
1. sugar use
2. growth in CO2
3. pigment production
4. capsular formation

74

What two enzymes do anaerobes lack that do not allow them to detoxify oxygen biproducts?

1. superoxide dismutase
2. catalase

75

Anaerobes are the predominant species in what four body regions?

1. mouth
2. GI tract
3. GU tract
4. Skin appendages (hair follicles and sweat glands)

76

Mouth flora is a mixture of _______ and ________/

viridans streptococci and anaerobes

77

Anaerobes comprise what percent of the colonic flora?

99.99%

78

What diseases are caused by anaerobes in the mouth?

1. Peridontal disease
2. Oral and pharyngeal absess
3. Lung absess

79

What diseases are caused by anaerobes in the GI tract?

intraabdominal abscesses

80

What diseases are caused by anaerobic bacteria in the GU tract?

Pelvic inflammatory disease and tubo-ovarian abscesses

81

What are the 5 main anaerobes that infect the head and neck?

1. bacteroides
2. fusobacterium
3. porphyromonas
4. prevotella
5. veillonella

82

What are the 2 main anaerobes that cause intraabdominal abscesses and gynecologic problems?

1. bacteroides
2. prevotella