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Flashcards in Gram (-) Deck (96):
1

gram (-) - colour

pink

2

Gram (-) - subgroups

1. diplococci
2. coccoid robs (cocciobacilly)
3. robs
4. oxidase (+) comma shaped robs

3

Gram (-) - subgroups - diplococci - bugs and maltose

1. Neisseria meningitis (malose)
2. Neisseria gonorrhoeae (non-maltose)
3. Moraxella catarrhalis (non-maltose)

4

Gram (-) - subgroups - diplococci - neisseria - bugs (and characteristics

1. Neisseria meningitis (maltose fermenter, polysaccharide capsule, glucose fermenter)
2. Neisseria gonorrhoeae (maltose nonfermenter, no capsule, glucose fermenter)

5

Gram (-) - subgroups - coccoid robs - bugs?

1. haemophilus infleunzae
2. Pasteurella
3. Brucella
4. Bordetella pertusis
5. Francicella tularencis

6

Pasteurella - transmission by

animal bite

7

H. influenza - media (and its contains)?

Chocolate agar - Factor V (NAD+) and X (hematin)

8

Gram (-) - subgroups - oxidase +, comma shape

1. Campylobacter jejuni (grows in 42c, oxidase +, comma shape)
2. Vibrio cholera (grows in alkaline media, oxidase +, comma shape)
3. Helicobacter pylori (produces urease, oxidase +, comma shape, catalase +)

9

Gram (-) stain robs are divided to (only the groups)

1. Lactose fermeter
2. Lactose nonfermenter

10

Gram (-) stain robs - Lactose nonfermenter are divided to

oxidase -
oxidase +

11

Gram (-) stain robs - oxidase (+) Lactose nonfermenter - bugs (and their characeristic)

Pseudomonas - rob, oxidase (+),

12

Gram (-) stain robs - oxidase (-) Lactose nonfermenter - are divided to

H2S producers and non producers (TSI AGAR)

13

Gram (-) stain robs - oxidase (-) Lactose nonfermenter - bags and their characteristics

1. Salmonela - lacose nonfermeter, oxidase -, H2S producer
2. Proteus - lacose nonfermeter, oxidase -, H2S producer
3. Yersinia - lacose nonfermeter, oxidase -, not H2S producer
4. Shigella - lacose nonfermeter, oxidase -, not H2S producer

14

Gram (-) stain robs - lactose non fermenter bugs

1. pseudomonas
2. shigella
3. salmonella
4. proteus
5. Yersinia

15

Gram (-) stain robs - lactose fermenter bugs (and characteristics)

1. klebsiella (rob, fast lactose fermenter)
2. E. coil (rob, fast lactose fermenter)
3. Enterobacter (rob, fast lactose fermenter)
4. citrobacter (rob, slow lactose fermenter)
5. serratia (rob, fast lactose fermenter)
6. others (rob, fast lactose fermenter)

16

Gram (-) stain robs - lactose fermenter are divided to

fast and slow fermenters

17

Gram (-) stain - lactose fermatation - appearance

fermantation of lactose --> fermentation produces acid pink colonies on MacConkey agar

18

lactose fermatation - agar?

MacConkey agar

19

E. coli is a lactose fermenter - mechanism

E. coli produces β-galactosidae, which breaks down lactose into glucose and galactose

20

EMB

eosin-methylane blue agar

21

EMB - lactose fermenting bacteria -->

lactose fermenters grow as purple/black colonies
E. coli grows colonies with a green sheen

22

Neisseria - media (and its contains)?

Thayer - Martin - vancomicin , trimethoprim, colistin , nystatin

23

Thayer - Martin contains ... (and action)

1. vancomicin --> inhibits gram (+)
2. trimethoprim
3. colistin --> inhibits gram (-) except Neisseria
4. nystatin --> inhibits fungi

24

neisseria produce (virulence factor)

IgA protease

25

neisseria gonococci vs neisseria meningitis - capsule

neisseria gonococci --> no capsule
neisseria meningitis --> polysaccharide capsule

26

neisseria gonococci vs neisseria meningitis - maltose fermentation

neisseria gonococci --> no
neisseria meningitis --> yes

27

neisseria gonococci vs neisseria meningitis - vaccines

neisseria gonococci --> no
neisseria meningitis --> yes (type B not widely available)

28

neisseria gonococci vs neisseria meningitis - transmission (via)

neisseria gonococci --> sexual or perinatally
neisseria meningitis --> respiratory or oral secretions

29

neisseria gonococci vs neisseria meningitis - manifestations

neisseria gonococci --> 1. gonorrhea, 2. septic arthritis, 3. neonatal conjunctivitis, 4. PID, 5. Fitz-Hugh-Curris syndrome, 6. prostatitis, 7. epididymitis, 8. osteomyelitis (RARE)
neisseria meningitis -->1. meningococcemia with petechial hemor and gangrene of toes, 2. meningitis, Waterhouse-Friderichsen syndrome (adrenal insuf, fecer, DIC)

30

neisseria gonococci vs neisseria meningitis - prevention

neisseria gonococci --> condoms (for STD), erythromycin ointment (neonatal transmision)
neisseria meningitis --> Rifampin, ciprofloxacin or ceftriaxone prophylaxis in close contacts

31

neisseria gonococci vs neisseria meningitis - treatment

neisseria gonococci --> ceftriaxone + (azithromycin or doxycycline) for possible chlamydial coinfection
neisseria meningitis --> ceftraxone or penicillin G

32

neisseria gonococci vs neisseria meningitis - intracellular

neisseria gonococci --> yes
neisseria meningitis --> no

33

neisseria gonococci - vaccination

no --> due to antigenic variation of pilus proteins

34

MC complications in men and women of gonococcal urethritis

men: epididymitis, prostatitis, urethral strictures
women: sterility, ectopic pregnancy, peritonitis, perihepatitis

35

what type of immunodeficiency has the greatest risk of N. meningitides bacteremia

C6-C9 deficiency

36

Waterhouse-Friderichsen syndrome?

fulminant meningococcemia leading to septic shock and bilateral adrenal hemorrhage causing catastrophic adrenal insufficiency and deaths in hours

37

Gram (-) - subgroups - coccoid robs - bugs?

1. haemophilus infleunzae
2. Pasteurella
3. Brucella
4. Bordetella pertusis
5. Francicella tularencis

38

haemophilus infleunzae - characteristics

small gram (-) coccoid robs (coccobacillary)

39

haemophilus infleunzae - transmission

aerosol transmission

40

H. influenza - media (and its contains)?

Chocolate agar - Factor V (NAD+) and X (hematin)

41

H. influenza - stains (clinical relevance)

1. Nontypeable stains (non-vaccine)
2. tybe b stain (vaccine)

42

Nontypeable stains are the MCC of

A. mucosal infection:
1. otitis media
2. conjunctivitis
3. bronhitis

43

H. influenza produces

IgA protease

44

H. influenza can also be grown with .....

S. aureus, which provides factor V (NAD+) through the hemolysis of RBCs.

45

en-capsuled type B H. influenza causes

invasive infection:
1. meningitis
2. acute epiglottitis (children)
3. septic arthritis
4. sepsis

46

acute epiglottitis - appearance

endoscopy: cheery red
x-ray: thumbprint signs (thickening of epiglottis on lateral neck radiograph)

47

H. influenza - treatment

1. mucosal infection --> amoxicillin +/- clavulanate
2. meningitis --> ceftriaxon.

48

H. influenza - prophylaxis in close contacts

rifampin

49

H. influenza - prevention / given when

vaccine contains type b capsular polysaccharide and PRP (polyribosylribitol phosphate) conjugated to diptheria or other protein
given between 2 and 18 monthes of age

50

Legionella pneumonophila - characteristics

gram (-), --> gram stains poorly

51

Legionella pneumonophila - staining

gram ((-)) stains poorly --> SILVER STAIN

52

silver stain is used to stain

1. Fungi (eg. Pneumocytosis)
2. Legionella
3. Helicobacter pylori

53

Legionella - media?

charcoal yeast extract agar buffered with cysteine and iron

54

Legionella - detection

1. by presence of antigen in urine
2. Labs may show hyponatremia

55

Legionella - transmission

--> aerosol transmission from environmental water source habitat (eg. air condition systems, hot water tanks)
(NO PERSON - PERSON)

56

Legionella - treatment

macrolide or quinolone

57

Legionella pneumophilla --> ....

1. Legionnaires's disease
2. Pontiac fever

58

Legionnaires's disease?

severe pneumonia (often unilateral and lobar), fever, GI and CNS symptoms

59

Pontiac fever is caused by / manifestation

- Legionella pneumophilla
- mild flu-like syndrome

60

risk factors for Legionnaires's disease

1. Cigarette smoking
2. alcoholics
3. chronic lung disease
4. immunosuppressed states

61

Pseudomonas aeroginosa - characteristics

Aerobic, motile, gram (-) rob, Non lactose fermenting, oxidase (+)

62

Pseudomonas aeroginosa - oxidase? / lactose?

- oxidase +
- Non lactose fermenting

63

Pseudomonas aeroginosa - appearance

1. pyocacin (blue-green pigment)
2. grape-like odor

64

Pseudomonas aeroginosa - mechanism of action

produce
1. endotoxin --> fever + shock
2. exotoxin A --> inactivates EF-2
3. pyocacin --> generates ROS

65

pseudomonas aeroginosa - manifestations (and associated conditions)

1. Pneumonia (Cystic fibrosis, mechanical ventilation)
2. otitis externa - swimmer's ear (diabetes)
3. UTI (hospital patients)
4. ecthyma gangrenosum (immunocompromised patients)
5. sepsis
6. osteomyelitis (eg. puncture wounds, drug use)
7. wound infection (burn victim)
8. hot tub folliculitis (water)
9 nosocomial infections (catheter equipment)

66

ecthyma gangrenosum - definition and appearance

rapidly progressive necrotic lesion caused by pseudomonas aeroginosa. Large ulcers with necrotic regions. Typically seen in immunocompromised patients

67

conditions associated with pseudomonas aeroginosa infection

1. Cystic fibrosis
2. mechanical ventilation
3. hospital
4. immunodeficiency
5. puncture wounds
6. drug use
7. water
8. burn victim

68

pseudomonas aeroginosa - pneumonia - mechanism of action

Mucoid polysaccharide capsule may contribute t ochronic pneumonia in cystic fibrosis patietns due to biofilm formation

69

Pseudomonas aeroginosa - treatment

1. extended spectrum β-lactams (eg piperacillin, ticarcillin, cafepime)
2. Carbapenems (eg imipenem, meropenem)
3. Monobactams (eg aztreonam)
4. Fluoroquinolones (eg ciprofloxacin)
5. Aminoglycosides (eg. gentamycin, tobramicin)
6. For multidrug resistant stains --> colistin, polymyxin B
7. 3rd and 4th generation cephalosporines

70

Pseudomonas aeroginosa - treatment for multidrug resistant stains

colistin
polymyxin B

71

Pseudomonas aeroginosa - otitis externa - swimmer's ear is associated with

diabetes

72

Pseudomonas aeroginosa - UTI is associated with

hospital patients

73

Pseudomonas aeroginosa - osteomyelitis is associated with

puncture wounds, drug use

74

Pseudomonas aeroginosa - wound infection is associated with

burn victim

75

Pseudomonas aeroginosa - hot tub folliculitis is associated with

water

76

Pseudomonas aeroginosa - eye

it can cause corneal ulcer in contact lens wearers

77

E coli - virulence factors and associated diseases

1. fibmbriae --> cystitis and polynephritis (P-pili)
2. capsule (K) --> pneumonia, neonatal meningitis
3. LPS --> septic shock

78

E coli - strains

1. EIEC (Enteroinvasive)
2. ETEC (Enterotoxigenic)
3. EPEC (Enteropathogenic)
4. EHEC (Enterohemorrhagic)

79

EIEC (Enteroinvasive) - toxins and mechanism

main virulence factors by plasmid shared by shigella --> proteins for adherence and direct invasion (no toxins) invades intestinal mucosa and causes necrosis and inflammation

80

EIEC (Enteroinvasive) - presentation

dysentery with white blodd cells
fever
(similar to shigella)

81

ETEC (Enterotoxigenic) - main virulence factors

produce heat-labile and heat stable toxin enterotoxins
NO INFLAMMATION OR INVASION

82

ETEC (Enterotoxigenic) - presentation

traveler's diarrhea (watery)

83

Head-labile toxin (LT) - mechanism of action

Overactivates adenylate cyclase (increases cAMP) --> increases CL- secretion in gut and H20 efflux

84

Head-stable toxin (ST) - mechanism of action

overactivates guanylate cyclase (increases cGMP) --> decreases resorption of NaCL and H20 in gut

85

EPEC (Enteropathogenic) - toxins and mechanism

No toxins
Adheres to apical surface, flattens villi --> prevent absorption

86

EPEC (Enteropathogenic) - presentation

watery diarrhea, usually in children

87

EHEC (Enterohemorrhagic) - toxin and mechanism

shiga - like toxin -->
a. enhances cytokines release --> hemolytic uremic syndrome
b. GI mucosa damage --> dysentery

88

Shiga like toxin - mechanism of action

inactivates 60S ribosome by removing adenine from rRNA

89

hemolytic uremic syndrome -->

triad of anemia, thrombocytopenia and acute renal failure due to microthrombi forming on damage enthothelium --> mechanical hemolysis (schistocytes on peripheral smear, platelet consumption, and decreased renal flow

90

EHEC (Enterohemorrhagic) - presentation

1. dysentery (toxin alone causes necrosis and inflammation)
2. triad of hemolytic uremic syndrome (anemia, thrombocytopenia and acute renal failure)

91

hemolytic uremic syndrome - peripheral smear

schistocytes

92

EHEC (Enterohemorrhagic) is also called / MC serotype is US

STEC (shiga toxin-producing E. col)
O157:H7

93

E-coli is a lactose fermenter - mechanism

E. coli produces β-galactosidae, which breaks down lactose into glucose and galactose

94

how to distinguish EHEC from other E. coli

EHEC does not ferment sorbitol

95

E. coli - presentation

1. EIEC --> dysentery with white blood cells, fever
2. ETEC --> traveler's diarrhea (watery)
3. EPEC --> watery diarrhea, usually in children
4. EHEC --> dysentery, hemolytic uremic syndrome

96

EHEC - trasnmission

undercooked meat, raw leafy vegetables