Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MTAP FIRST SEM 2024-2025 > GRAM NEGATIVE BACILLI AND COCCOBACILLI (ENTEROBACTERIACEAE) > Flashcards

GRAM NEGATIVE BACILLI AND COCCOBACILLI (ENTEROBACTERIACEAE) Flashcards

1
Q

What are the key metabolic characteristics of Enterobacteriaceae?

A

Ferment glucose
Reduce nitrate to nitrites
Oxidase-negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

types of antigens found in Enterobacteriaceae

Found in the bacterial cell wall

A

Somatic or O antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

types of antigens found in Enterobacteriaceae

Found in the flagella

A

Flagellar or H antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

types of antigens found in Enterobacteriaceae

Found in the bacterial capsule

A

Capsular or K antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the differentiating and selecting agents in MacConkey (MAC) agar?

A

Differentiating Agent: Lactose
Selecting Agents: Crystal violet, Bile salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do lactose-positive and lactose-negative colonies appear on MacConkey (MAC) agar?

A

Lactose Positive: Dark pink
Lactose Negative: Transparent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the differentiating and selecting agents in Eosin Methylene Blue (EMB) agar?

A

Differentiating Agents: Sucrose, Lactose
Selecting Agents: Eosin Y, Methylene blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do lactose-positive and lactose-negative colonies appear on Eosin Methylene Blue (EMB) agar?

A

Lactose Positive: Green sheen, purplish, and brownish amber

Lactose Negative: Transparent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the differentiating and selecting agents in Hektoen Enteric (HE) agar?

A

Differentiating Agents: Lactose, Sucrose, Salicin
Selecting Agent: Bile salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do lactose-positive and lactose-negative colonies appear on Hektoen Enteric (HE) agar?

A

Lactose Positive: Salmon
Lactose Negative: Green to blue, H2S positive colonies have black centers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the differentiating and selecting agents in Salmonella-Shigella (SS) agar?

A

Differentiating Agent: Lactose
Selecting Agents: Brilliant green, Bile salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do lactose-positive and lactose-negative colonies appear on Salmonella-Shigella (SS) agar?

A

Lactose Positive: Red
Lactose Negative: Transparent, H2S positive colonies have black centers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the differentiating and selecting agents in Xylose Lysine Deoxycholate (XLD) agar?

A

Differentiating Agents: Lactose, Sucrose, Xylose
Selecting Agent: Bile salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do lactose-positive and lactose-negative colonies appear on Xylose Lysine Deoxycholate (XLD) agar?

A

Lactose Positive: Yellow
Lactose Negative: Transparent on red medium, H2S positive colonies have black centers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Ability to ferment glucose, lactose, and sucrose
Production of hydrogen sulfide

A

Triple Sugar Iron Agar (TSI)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What indicators are used in the Triple Sugar Iron Agar (TSI) test?

A

Phenol red for acidification
Ferrous sulfate for H2S formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

It tests the ability of the organism to produce the enzyme tryptophanase and deaminate tryptophan to indole, pyruvic acid, and ammonia.

A

Indole Production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are positive and negative results indicated in the Indole Production test?

A

Positive: Pink to wine-colored ring after addition of reagents
Negative: Yellow color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

It detects bacteria that metabolize glucose by the mixed acid pathway, leading to a decrease in the pH of the medium.

A

Methyl Red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How are positive and negative results indicated in the Methyl Red test?

A

Positive: Red color (when medium reaches a pH of 4.5)
Negative: Yellow color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

It detects end products of glucose fermentation by the butylene glycol pathway.

A

Voges-Proskauer test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How are positive and negative results indicated in the Voges-Proskauer test?

A

Positive: Red color (presence of acetoin)
Negative: Yellow color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

It determines if an organism can utilize sodium citrate as a sole source of carbon.

A

Citrate Utilization Test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What indicator is used in the Citrate Utilization Test?

A

Bromthymol blue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How are positive and negative results indicated in the Citrate Utilization Test?

A

Positive: Growth on the medium with or without color change (green to blue)
Negative: Absence of growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

It determines the ability of the organism to reduce nitrate to nitrite.

A

Nitrate Reduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How is a positive result indicated in the Nitrate Reduction test?

A

Red color.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

It uses a semisolid medium to demonstrate motility.

A

Motility test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How is a positive result indicated in the Motility test?

A

Haziness along the stab line.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

It detects organisms that produce urease, which hydrolyzes urea to form ammonia.

A

Rapid Urease Test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How is a positive result indicated in the Rapid Urease Test?

A

Bright pink color.

32
Q

It detects slow lactose fermenters.

A

ONPG (beta-galactosidase)

33
Q

How are positive and negative results indicated in the ONPG test?

A

Positive: Yellow color within 20 minutes to 24 hours
Negative: Colorless after 24 hours

34
Q

It determines the ability of an organism to oxidatively deaminate phenylalanine to phenylpyruvic acid.

A

Phenylalanine Deamination

35
Q

How are positive and negative results indicated in the Phenylalanine Deamination test?

A

Positive: Intense green color
Negative: No color change

36
Q

What indicator is used in Carbohydrate Fermentation tests?

A

Phenol red.

37
Q

How is a positive result indicated in Carbohydrate Fermentation tests?

A

Yellow color.

38
Q

What are the key biochemical characteristics of Escherichia coli?

A

Indole and lactose positive
IMViC: + + - -

39
Q

How does Escherichia coli appear on EMB or MacConkey agar?

A

greenish metallic sheen.

40
Q

What is the most common cause of urinary tract infections (UTIs) in females?

A

Escherichia coli.

41
Q

What are the key factors in the pathogenesis of Escherichia coli?

A

Pili
Flagellum (H antigen)
Capsule (K antigen)
Endotoxin (O antigen)
Enterotoxin

42
Q

What condition is caused by Enterotoxigenic E. coli (ETEC)

A

Watery diarrhea.

43
Q

What condition is caused by Enteropathogenic E. coli (EPEC)?

A

Watery diarrhea of long duration, mostly in infants, often in developing countries.

44
Q

What conditions are caused by Enterohemorrhagic E. coli (EHEC)?

A

Bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS).

45
Q

What condition is caused by Enteroinvasive E. coli (EIEC)?

A

Bloody diarrhea.

46
Q

What condition is caused by Enteroadherent E. coli (EAEC)?

A

Persistent watery diarrhea in children and patients with HIV.

47
Q

IDENTIFY

Lactose negative
Non-lactose fermenting
Non-motile
Anaerogenic
Have O antigen
Cultured in XLD

A

Shigella

48
Q

How is Shigella transmitted?

A

Via the fecal-oral route.

49
Q

What disease is caused by Shigella and what are its symptoms?

A

Bacillary dysentery

-Penetrate the epithelial cells in the small intestine
-Incubation period: 1-4 days
-Fever abdominal cramps, followed by watery then bloody diarrhea
-Diarrhea frequently resolves in 2 or 3 days

50
Q

Which Shigella species is the most severe?

A

Shigella dysenteriae (Group A).

51
Q

Which Shigella species is the most common?

A

Shigella sonnei (Group D).

52
Q

How many Shigella organisms are needed to cause disease?

A

Fewer than 200 organisms.

53
Q

IDENTIFY

Facultative gram-negative rods with a large polysaccharide capsule
Non-motile
Urease positive
Ornithine negative
VP positive

A

Klebsiella

54
Q

Where are Klebsiella commonly found in the human body?

A

Inhabitants of the nasopharynx and gastrointestinal tract (GIT).

55
Q

What type of pneumonia is caused by Klebsiella and what are its symptoms?

A

Type: Necrotizing pneumonia

Symptoms: Thick, bloody sputum (“currant jelly” sputum), usually nosocomial, most common cause in alcoholics

56
Q

What other infection is commonly caused by Klebsiella?

A

Urinary tract infection (UTI).

57
Q

How many Salmonella organisms are typically needed to cause an infection?

A

More than 100,000 organisms

58
Q

IDENTIFY

Facultative gram-negative rods
Non-lactose fermenting
Cultured on XLD medium
H2S positive
Lysine positive
Indole negative
Urea negative

A

SALMONELLA

59
Q

What is the Widal test used for?

A

It detects antibodies in the patient’s serum.

60
Q

Salmonella typhi typically found?

A

In the human colon only.

61
Q

Salmonella enteritidis typically found?

A

In the enteric tract of humans and animals (chicken and domestic livestock).

62
Q

How is Salmonella transmitted?

A

Via the fecal-oral route.

63
Q

What condition is caused by Salmonella enteritidis and Salmonella typhimurium, and what is its incubation period?

A

Condition: Enterocolitis
Incubation Period: 12-48 hours
Common Source: Undercooked chicken

64
Q

What condition is caused by Salmonella typhi, and what are its key features?

A

Condition: Typhoid fever

Key Features: Vi (virulence) capsular antigen, multiplies in the Peyer’s patches, predilection to the gallbladder

Incubation Period: 5-21 days

65
Q

What condition is caused by Salmonella choleraesuis, and who is commonly affected?

A

Condition: Septicemia

Commonly Affected: Patients with sickle cell anemia or cancer

66
Q

IDENTIFY

Urea positive
Deaminase positive
Motile
Burnt chocolate or chocolate cake odor

A

Proteus

67
Q

IDENTIFY

Indole positive
H2S positive

A

Proteus vulgaris

68
Q

IDENTIFY

Facultative gram-negative rods
Non-lactose fermenting
Urease positive
Swarming motility
Indole negative

A

Proteus mirabilis

69
Q

What type of infection is commonly associated with Proteus mirabilis?

A

Complicated urinary tract infection (UTI) associated with nephrolithiasis (staghorn calculi).

70
Q

IDENTIFY

Motile
Lactose fermenters
Mucoid colonies
Associated with contaminated medical devices (e.g., respirators and other medical instruments)
Ingested from water, vegetables, and food products

A

Enterobacter

71
Q

IDENTIFY

-Motile, slow lactose fermenters
-Produces red pigment (prodigiosin) especially in S. marcescens
-DNAse, ONPG, and gelatinase positive
-VP positive
-Transmission may be person-to-person but often associated with contaminated medical devices

A

Serratia

72
Q

IDENTIFY

Gram-negative
Catalase, oxidase, and indole positive
Non-lactose fermenters
Facultative anaerobes capable of growth at 4-43°C

A

Yersinia

73
Q

IDENTIFY

Transmission: Bite of an infected flea,handling infected animals, inhaling infectious droplets, ingestion of undercooked meat, and human-to-human (pneumonic form)

Disease: Bubonic plague

Appearance: Small gram-negative rods with bipolar (safety pin) staining

A

Y. pestis

74
Q

IDENTIFY

Habitat: GIT of swine, rodents, and dogs

Transmission: Ingestion of contaminated food or water

Growth: Optimal at room temperature (RT), cold enrichment

Properties: Invasive and toxigenic

A

Yersinia enterocolitica

75
Q

IDENTIFY

Habitat: Wild and domesticated animals (rodents, birds, and rabbits)

Transmission: Contact with infected animals or ingestion of contaminated food or water

Disease: Acute mesenteric lymphadenitis and “pseudo tubercles”

A

Yersinia pseudotuberculosis

MTAP FIRST SEM 2024-2025 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions