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BACTERIOLOGY > Haemophilus and the HACEK group > Flashcards

Haemophilus and the HACEK group Flashcards

1
Q

General characteristic of Pasteurellaceae family

A 
-facultative anaerobes
• Gram (-)
• pleomorphic
• coccoid-shaped to rod-shaped cells
• nonmotile
•reduction of nitrates to nitrites
• oxidase & catalase (+)
- obligate parasites (exp. Haemophilus ducreyi)
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2
Q

4 genera of Pasteurellaceae family

A

Haemophilus
Actinobacillus
Pasteurella
Aggregatibacter

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3
Q

HACEK

A
  • Haemophilus
  • Aggregatibacter
  • Cardiobacterium
  • Eikenella
  • Kingella
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4
Q

Where do HACEK organism resides

A
  • oral cavity
  • nasopharynx

some spp can cause ENDOCARDITIS

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5
Q

General characteristics of Haemophilus

A 
Gram (-)
•  coccobacilli 
• pleomorphic
• nonmotile
•reduce nitrates to nitrites
• ferment carbohydrates
• oxidase & catalase (+)
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6
Q

Major pathogenic spp of Haemophilus

A

H. influenzae
H. aegyptius
H. ducreyi

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7
Q

Haemophilus require ______ to grow

A

“blood lovers”

require preformed growth factors present in blood the X and V factor

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8
Q

Growth factor in blood referred as HEMIN or HEMATIN

A

X factor

X stands for unknown

-When Haemophilus spp. are grown
anaerobically, they do not require heme but still require NAD

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9
Q

Growth factor in blood referred to as NICOTINAMIDE ADENINE DINUCLEOTIDE (NAD factor)

A

V factor

V stands for vitamin
- When Haemophilus spp. are grown
anaerobically, they do not require heme but still require NAD

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10
Q

Haemophilus spp. with “PARA” needs what growth factor

A

need only V factor for growth

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11
Q

Haemophilus spp. with “PARA” does not grow on this type of medium

A

SBA medium

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12
Q

On what medium Haemophilus spp. are isolated and recovered

A
  • Chocolate agar

- because the lysis of RBC in this medium releases both X and V factor & inactivates NADases

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13
Q

The Haemophilusisolate gets X factor from the SBA & V factor from one of the organisms, except;

Neisseria spp.
Streptococcus pneumoniae
Staphylococcus aureus
Escherichia coli

A
  • Escherichia coli

Staphylococcus aureus, Streptococcus
pneumoniae, or Neisseria spp., produces
V factor as a by-product of metabolism

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14
Q

This phenomenon happens when an organism, such as
Staphylococcus aureus, Streptococcus
pneumoniae, or Neisseria spp., produces
V factor as a by-product of metabolism

A

SATELLITISM

  • helps recognition of haemophilum spp that need V factor for growth.
  • Haemophilus spp. grows around colonies of these organisms
  • In SBA agar
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15
Q

V factor producing organisms

A
  • Staphylococcus aureus

- Streptococcus pneumoniae - Neisseria spp.

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16
Q

Haemophilus Influenzae:

Virulence factors

A
  • Capsule
  • IgA protease
  • Fimbriae
  • outer membrane proteins and LPS
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17
Q

the only member of the heamophilus genus that produces IgA
protease (can cleave secretory
IgA)

A

H. influenzae

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18
Q

What virulence factor of H. influenzae plays the most significant role in infection.

A

Capsule

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19
Q

type of H. influenzae capsule that has antiphagocytic and anticomplementray activity and is the leading cause of meningitis

A

Type B capsule

  • Hib strain
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20
Q

what do you call group of H. influenzae that is not encapsulated

A
  • non-typeable H. influenzae (NTHi)
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21
Q

2 patterns of H. influenzae infection

A

INVASIVE & LOCALIZED

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22
Q

Invasive infections of H. influenzae is caused by what type of strain

A

ENCAPSULATED STRAINS in which bacteremia plays a vital role

e.g., SAME PT septicemia, arthritis, meningitis, epiglottitis, pneumonia &
tracheitis

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23
Q

Localized infections of H. influenzae is caused by what type of strain

A
  • contagious spread of NHTi strains
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24
Q

in localized H. influenzae infections, what organ serves as the reservoir in chronic middle ear infections and that the bacteria develop biofilms *

spleen
tonsils
adenoid
kidneys
mesentery
gallbladder
A
  • adenoid
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25
Q

Haemophilus spp associated with acute contagious conjunctivitis: pinkeye

A

Haemophilus aegyptius

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26
Q

Haemophilus spp that can cause severe systemic
disease: Brazilian purpuric
fever (BPF)

A

Haemophilus influenzae

biogroup aegyptius

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27
Q

causes severe systemic disease: Brazilian purpuric fever (BPF) *

Haemophilus aegyptius
Haemophilus ducreyi
Haemophilus influenzae biogroup aegyptius
none of the choices
all of the first three choices
A

Haemophilus influenzae biogroup aegyptius

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28
Q

Recovered using CA(RBC heat lysis releases BOTH both X factor & Vfactor & inactivates *

RNAses
DNAses
NADses
isomerases
none of the choices
A

NADses

-enzyme that hydrolyzes V factor

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29
Q

Haemophilus influenzae causes ocular infections(pinkeye) and requires X and V factors in the primary medium for growth. The subspecies Haemophilus influenza (biogroup) aegyptius can further be identified and differentiated by which two tests? *

A. Indole and xylose
B. Glucose and urease
C. Oxidase and catalase
D. ALA test and oxidase

A

A. Indole and xylose

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30
Q

Haemophilus spp that is the causative agent of
chancroid
“soft chancre”

a highly communicable
sexually transmitted genital
ulcer disease (GUD)

A

Haemophilus ducreyi

  • most common site of infection is penis or labia
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31
Q

a suppurative (pus-
forming), enlarged, draining,
inguinal lymph nodes

A

Buboes

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32
Q

Haemophilus spp that can cause otitis media & acute sinusitis and is related to endocarditis: insidious onset

A

H. parainfluenzae

33
Q

primary site of infection of H.parainfluenzae

A

Mitral valve

34
Q

It is the recommended specimen for culture of the lower respiratory tract for h. influenzae organisms

A

Bronchial Washing

35
Q

Additional Info

A

specimen processing in the laboratory should
occur soon after collection for maximum
recovery

Since:
- Haemophilus spp. dies rapidly in clinical specimens
- Haemophilus spp. are susceptible to
drying)

36
Q

H. influenzae in chocolate agar

A
  • incubated between 33° & 37° C
  • growth after 18 to 24 h of incubation
    in an atmosphere of 5% - 10% CO2 (high humidity)
37
Q

It is an excellent medium for the
isolation of Haemophilus spp. from
respiratory specimens

A
  • CA supplemented with bacitracin (300
    mg/L)
  • Bacitracin: reduces overgrowth
    of normal respiratory microbiota
38
Q

What does the growth of tan mucoid colonies of H. influenzae in chocolate agar indicate?

A
  • charcateristics of encapsulated strains
39
Q

Special media for H. aegyptius is composed of :

A
  • enriched CHOC agar supplemented with 1% Iso- VitaleX or Vitox
40
Q

Special media for H. ducreyi is composed of:

A
  • enriched CHOC medium, or Nairobi biplate

- grows best at 33° C

41
Q

Characteristics of H.influenzae in Chocolate agar

A
  • translucent, tannish, moist, smooth, &convex

- “mousy” or bleachlike odor

42
Q

Characteristics of H.parainfluenzae and H. parahaemolyticus in Chocolate agar

A
  • Tannish & drier with a medium to large size compared with H. influenzae
43
Q

Characteristics of H. ducreyi in Chocolate agar

A
  • small, flat, smooth, nonmucoid, transparent to opaque

colonies or appears tan or yellow

44
Q

Haemophilus spp. do not grow on what medium

A

MAC agar

45
Q

Microscopic morphology of H. influenzae in gram stain

A
  • capsules are clear, non-
    staining areas (“halos”) surrounding the organisms in purulent secretions
  • ## small pleomorphic stains “FAIINT PINK”
46
Q

Due to the low specificity and sensitivity of Heamophilus in gram stain, these stains are used to help detect the latter

A

acridine orange & methylene blue stain

47
Q

Microscopic morphology of H. ducreyi in gram stain

A
  • singly or in groups (clusters)/“SCHOOL OF FISH ”or “RAILROAD TRUCKS”
  • are loosely coiled clusters of organisms lined up in parallel or appearing as “FINGERPRINTS”
48
Q

This can be the first clue to help indicate

that the organism being isolated is Haemophilus

A
  • growth of gram (-) pleopmorphic coccobacilli on CHOC agar w/ NO growth on SBA and MAC agar in pure culture
  • these 3 test must be done simultaneously
  • satellitation can occur on SBA if it’s not pure culture
49
Q

In laboratory identification, if a Haemophilus spp. requires both X and V factor for growth, what does it indicate?

A
  • the organism growing is H. influenzae
50
Q

In laboratory identification, if a Haemophilus spp. requires only V factor for growth, what does it indicate?

A
  • the organism is identified as H. parainfluenzae or H. parahaemolyticus
51
Q

In laboratory identification, if a Haemophilus spp. requires only X factor for growth, what does it indicate?

A
  • the organism growing can be Aggregatibacter aphrophilus

- bcs this spp. can appear to be hemin dependent on initial isolation.

52
Q

This is an alternative method for differentiating the heme-producing species of Haemophilus

A

Porphyrin test

53
Q

Principle of Porpphyrin test

A
  • is based on the ability of the organism to convert the substrate δ-aminolevulinic acid (ALA) into porphyrins or porphobilinogen (intermediates in
    the synthesis of X factor)
54
Q

In porphyrin test, porphobilinogen can be detected after 4hrs of incubation in 35° C through the addition of

A
  • p-dimethylaminobenzaldehyde (Kovac rgt)

- (+ for porphobilinogen) = RED color forms [lower aqueous phase]

55
Q

In porphyrin test, porphyrins can be detected using

A
  • UV light: wavelength - 360 nm

- reddish-orange color under UV light

56
Q

Advantage and Disadvantage of Porphyrin test

A

Advantage:
- X factor is not required and the problem of carryover is eliminated

Disadvantage:
- primary ID is based on a negative test result

57
Q

Primary identification of Heamophilus spp. in porphyrin test is base on what result?

A

Negative result = presence of organism

-e.g., H. influenzae

negative = no fluorescence (UV light test) + no color change occurs after addition of the Kovacrgt

58
Q

the recommended treatment of life-threatening illness caused by H. influenzae

A
  • cefotaxime or ceftriaxone

alternative drugs
• trimethoprim-sulfamethoxazole
• imipenem
• Ciprofloxacin

59
Q

Hamephilus shows increased resistance in this antimicrobial drugs

A
  • Ampicillin (Should not be administered alone)
60
Q

General characteristics of HACEK group

A
  • include both fermentative and non-fermentative gram (-) bacilli
  • fastidious
  • ehnaced growth w/ CO2
  • are opportunist & generally require a comprimised host
61
Q

ACEK group

A
  • ACEK more dysgonic (slow/ poor growing)

- important cause of endocarditis

62
Q

Cardiobacterium is needs CO2 for growth thus they are considered as?

A

Capnophilic

63
Q

Risk factors for Infective (bacterial) endocarditis

A
  • tooth extraction
  • history of endocarditis
  • gingival surgery
  • Heart valve surgery
  • mitral valve prolapse
64
Q

General characteristics of Aggregatibacter aphrophilus

A
  • foam loving or desiring/ loves high conc. of CO2 (can grow w/out CO2 tho)
  • linked to bone & joint infections
  • found in dental plaque & gingival scrapings
65
Q

A. aphropilus growing over the entire surface of Trypticase soy agar plate is due to what reason

A
  • because they are not X factor dependent
66
Q

General characteristics of Aggregatibacter actinomycetemcomitans

A
  • has 6 serotypes (a-f)
  • A, B, and C is the most common
  • normal oral microbiota in humans
  • require >24 hr for visible growth
  • a distinctive “STAR SHAPE with four to six points” in
    the center of the colonies is often seen at 48 h
67
Q

Human tissue infection caused by A. actinomycetemcomitans is usually caused by

A
  • bites by sheep, pigs, cattle, and horses or through contact with these animals.
68
Q

Major virulence factors of A. actinomycetemcomitans

A
  • Collagenase

- Leukotoxin (toxic to PMNs and monocytes)

69
Q

Aggregatibacter spp. that is a major contributor to PERIODONTITIS

A
  • A. actinomycetemcomitans

can cause destruction of the alveolar bone that
supports teeth

70
Q

Biochemical test characteristic of A. actinomycetemcomitans

A
  • catalase (+)
  • Granular and adhere to sides of tube
  • urease, indole, esculin, citrate (-)
  • ## ferment glucose (+)
71
Q

General characteristics of Cardiobacterium hominis

A
  • nonmotile
  • pleomorphic
  • normal microbiota: nose, mouth & throat
  • infection can lead to Endocarditis infecting the AORTIC VALVE
72
Q

In Yeast extract Cardiobacterium hominis appear

A
  • tend to form ROSETTES, swellings or sticklike structures
73
Q

General characteristics of Eikenella corrodens

A
  • normal biota: oral and bowel cavities
  • cause of ADULT periodontitis, meningitis,
    empyema, pneumonia, osteomyelitis, arthritis, &
    postoperative tissue infections
74
Q

Eikenella corrodens manifest as ________ in drug addicts

A

Cellulitis

75
Q

Biochemical test characteristic of Eikenella corrodens

A
  • catalase (-)
  • oxidase (+)
  • nonmotile
  • YELLOW PIGMENT
  • “PIT” (make a depression) or CORRODES the surface of the agar
  • CHLORINE BLEACH–like odor from the agar surface adhere to the sides of the tube & produce
    granules
76
Q

General characteristics of Kingella spp.

A
  • important pathogens in the PEDIATRIC population

- the most common cause of OSTEOARTHRITIS infection in children younger than 4 years of age

77
Q

Biochemical test characteristic of Kingella spp.

A
  • resist decolorization in gram stain
  • oxidase (+)
  • catalase (-)
  • fermenters of glucose and other sugars but w/ no gas
  • susceptible to penicillin
78
Q

Kingella shares resemblance with this organism in MTM agar

A
  • Neisseria gonorrhoeae
79
Q

Kingella can grown in SELECTIVE agar such as

A
  • MTM or modified thayer- martim medium

BACTERIOLOGY (15 decks)

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