Gram Negative Bacteria Flashcards

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1
Q

Edward and Ewing classification of Enterobacteriacea

A

Escherichiae - E Coli, Shigella
Edwarsielleae - Edwardsidlla
Salmonellae - Salmonella
Citrobecterae - Citrobacter
Klebsielleae - Kleibsiella, Enterobacter, Serratia
Proteae - Proteus, Morganella
Yersinieae - Yersinia
Erwinieae - Erwinia

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2
Q

Gram Negative bacteria features

A

Non sporing
Aerobic
Peritrichous flagella
Glucose fermentation
Nitrate to Nitrite
Catalase +ve
Oxidase -ve

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3
Q

All Gram negative Bacteria arr motile except

A

Shigella
Salmonella gallinarum
Salmonella pullorum

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4
Q

All Gram negative organisms are Catalase positive except

A

Shigella dysenteriae - Catalse -ve

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5
Q

Classification of gram negative organisms on the basis of Lactose fermentation

A

Lactose fermenter
Non lactose fermenter
Late lactose fermenter

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6
Q

Examples of lactose fermenter

A

E coli
Kleibsiella
Enterobacter Citrobacter

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7
Q

Examples of Non lactose fermenter

A

Salmonella
Shigella
Proteus
Yersinia

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8
Q

Example of Late lactose fermenter

A

Shigella sonnei

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9
Q

Test for Lactose fermentation

A

MacConkey agar
CLED (Cystein lactose electrolyte deficient)
Eosin methylene blue

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10
Q

MacConkey agar consist of

A

PLANT
Peptone
Lactose - diff. Media
Agar
Neutral red - Indicator media
Taurocholate (Bile salts) - Selective media

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11
Q

MacConkey agar gives which color

A

Pretty Pink color

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12
Q

MacConkey agar is combination of

A

Differential media , indicator media and selective media

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13
Q

Indicator media for CLED

A

Bromothymol blue

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14
Q

CLED better than MacConkey agar because

A

It’s less inhibitory
Allow both gram Positive and gram negative to grow

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15
Q

CLED gives which color

A

Yellow

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16
Q

Eosin methylene blue shows which colonies and color

A

Blue Blackish colonies with green shin around it

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17
Q

Classification of Ecoli on the basis of Antigen

A

Somatic O (cell wall)
Capsular K antigen
Flagella H antigen

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18
Q

Toxins secreted by Ecoli

A

Hemolysin
Enterotoxins - Labile toxin, Stable toxin, Verocytotoxin/Shiga like toxin

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19
Q

Enterotoxin/Labile toxin fragments

A

Fragment A - increases cAMP
Fragment B - Binds to GM1 ganglioside
Labile in air

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20
Q

Stable toxin features

A

cGMP
Stable on ground

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21
Q

Mechanism of action of Shiga toxin or shiga like toxin

A

Decreases 60S ribosomes - decrease protein synthesis

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22
Q

Clinical features of Ecoli

A

UTI
Diarrhea
Meningitis
Sepsis
Pneumonia

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23
Q

Diarrheal strains of E Coli

A

EPEC(Enteropathogenic)
ETEC(Enterotoxigenic)
EIEC(Enteroinvasive)
EHEC(Enterohemorrhagic)
EAEC(Enteroaggregatory)
DAEC(Diffuselyadherent)

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24
Q

Enteropathogenic Ecoli causes

A

Pediatric/Infantile diarrhea (bcz it produces bundle forming pili) - Plasmid coded

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25
Q

Enteropathogenic Ecoli shows which lesion

A

Shows A/E Lesions (Attachment/Effacement lesion)

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26
Q

Enterotoxigenic Ecoli causes

A

Traveller’s Diarrhea
Large infectivity dose is needed
Colonisation factor antigen (CFA)

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27
Q

Enteroinvasive Ecoli causes

A

Dysentery (BLOOD + STOOLS)

28
Q

Antigen responsible for Traveller’s Diarrhea

A

Colonisation factor antigen (CFA)

29
Q

Antigen responsible for Dysentery caused by E coli

A

Virulence marker antigen (VMA)

30
Q

Enterohemorrhagic Ecoli causes

A

Hemolytic uremic Syndrome
Hemorrhagic Cystitis

31
Q

Most common cause of Hemolytic uremic syndrome

A

Ecoli 0157/H7

32
Q

Sereny test

A

Inoculation suspension of bacteria into Guinea’s pig - mucopurulent conjunctivitis and severe keratitis - indicates Positive test

33
Q

Sereny test is done for

A

EIEC
Shigella
Listeria monocytogenes

34
Q

Selective and differential medium used for detection of Enterohemorrhagic Ecoli

A

SMAC Test (Sorbitol McConkey agar) - 0157/H7 doesn’t shows this reaction

35
Q

Small infectivity dose is needed for which bacilli

A

CHHOTA SMALL
Cryptosporidium
E. Histolytica
Enterohemorrhagic Ecoli
Shigella
G. Lamblia

36
Q

Enteroaggregatory Ecoli causes

A

Persistent diarrhea (>14 day)

37
Q

Toxin involved in Enteroaggregatory Ecoli

A

EAST 1 Toxin

38
Q

Enteroaggregatory Ecoli on Hep2 cell line shows

A

Stagged brick appearance

39
Q

Sample in case of UTI due to Ecoli

A

Urine - fresh clean catch midstream urine
Suprapubic aspiration(Obstructive uropathy)
Catheter specimen not recommended

40
Q

Blood Agar finding for Ecoli

A

Hemolytic

41
Q

Finding of MacConkey agar for Ecoli

A

Pink color

42
Q

CLED Finding for Ecoli

A

Shows yellow color

43
Q

Selective media used for Ecoli diagnosis

A

DCA(Deoxycholate citrate agar)

44
Q

IMVIC Test

A

Indole test - Red color
Methyl red test - Red +
Voges Proskauer test - Red +
Citrate utilization test - Blue +

45
Q

Biochemical test findings/IMVIC of Ecoli

A

Ferment glucose/lactose
Indole +
Methyl red +
Voges Proskauer -ve
Citrate utilization test -ve

46
Q

IMVIC Test result in Ecoli and Klebsiella

A

++– (Ecoli)
–++ (Klebsiella)

47
Q

Treatment of Ecoli infection

A

Uncomplicated - Cotrimoxazole or Ciprofloxacin
Depends on sensitivity

48
Q

Shigella features

A

Non motile
Non sporing
Non encapsulated
Gram Negative bacilli
Low infective dose needed
No lactose fermentation

49
Q

All shigella species are Catalase +ve and shows Mannitol fermentation except

A

Shigella dysenteriae

50
Q

Shigella includes

A

Shigella dysenteriae
Shigella flexneri - M/C India
Shigella boydii
Shigella sonnei

51
Q

Which shigella species shows non lactose fermentation

A

S. Dysenteriae
S. Flexneri
S. Boydii

52
Q

Which shigella species shows late lactose fermentation

A

S. Sonnei - M/C worldwide

53
Q

Toxins release by Shigella

A

Exotoxin - Enterotoxin (SheT 1 and 2), Cytotoxin (Shiga toxin)
Endotoxin

54
Q

Pathogenesis of Shigella infection

A

Shigella enters with the help of M cells - Rupture Macrophages - then enters again via basolateral endocytosis - cell by cell actin polymerisation

55
Q

Antigens associated with shigella infection

A

Virulence marker Antigen (VMA)
Invasive Plasmid antigen (IPA)

56
Q

Incubation period of shigellosis

A

1-4 days

57
Q

Initial clinical manifestations of Shigellosis

A

Water diarrhea - Dysentery

58
Q

Complications of Shigellosis

A

Toxic megacolon
Perforation
Metabolic complications - Hypoglycemia, Hyponatremia

59
Q

Shigella encephalopathy is termed as

A

Ekiri Syndrome - Toxic encephalopathy, Delirium, Confusion

60
Q

HUS can be caused by

A

Enterohemorrhagic Ecoli
Shigella

61
Q

Reiter’s Syndrome includes

A

Reactive arthritis
Urethritis
Conjunctivitis

62
Q

IMVIC Test in Shigellosis

A

M SHY - Shigella, Yersinia
Methyl red +
IMVIC : -+–

63
Q

Transport media used in Shigellosis

A

SBGS (Sachs buffered Glycerol saline)

64
Q

Enrichment media or broth used in Shigella and Salmonella infection

A

Sclenite F broth
Tetrathionate B broth

65
Q

Selective media used for diagnosis of Shigella and Salmonella

A

XLD ( Xylase Lysine deoxycholate)
DCA (Deoxycholate agar)
SS (Salmonella Shigella agar)
HE (Hektoen enteric agar)