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Microbiology 1 > FASTIDIOUS GRAM NEGATIVE RODS.1 > Flashcards

FASTIDIOUS GRAM NEGATIVE RODS.1 Flashcards

INTRODUCTION AND HAEMOPHILUS INFLUEZAE

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Biology 101 flashcards
1
Q

What are fastidious bacterias

A

are microorganisms that have complex nutritional requirements and need specific conditions for their growth

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2
Q

difference between fastidious and non-fastidious bacteria

A

Fastidious bacterias have complex nutritional requirements and need specific conditions for their growth while non-fastidios bacteria can grow on general media

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3
Q

mention three medically important gram negative rods associated with respiratory tract

A
  1. Haemophilus influezae
  2. Bordetella pertussis
  3. Legionella pneumophila
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4
Q

mention zoonotic gram negative rods

A

Brucella species e.g Francisella tularensis, Yersinia pestis and pasteurella multocida

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5
Q

mention the gram negative rods related to the respiratory tract

A

Haemophilus Influezae
Legionella Pneumophila

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6
Q

Which gram negative rod related to the respiratory tract is primarily found in environmental water sources

A

Legionella pneumophila (L. pneumophila)

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7
Q

mention 3 characteristics of haemophilus species

A
  1. they are small nonmotile Pleomorphic gram-negative bacilli
  2. The cells are typically coccobacilli or short rods
  3. they are facultative anaerobes (produces energy with or without o2)
  4. Species of the genus Haemophilus require protoporphyrin IX (a metabolic intermediate of the hemin biosynthetic pathway)
  5. Except for Haemophilus ducreyi, Haemophilus spp. normally inhabit the upper respiratory tract of humans
  6. Organism is sensitive to drying and extremes in temperature
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8
Q

Mention 3 organisms of the haemophilus species

A
  1. Haemophilus influezae
  2. Haemophilus aegyptius
  3. Haemophilus ducreyi
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9
Q

What is the shape and Gram stain characteristic of Haemophilus influenzae?

A

Haemophilus influenzae is a small gram-negative rod (coccobacillus)

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10
Q

What is significant about the polysaccharide capsule of Haemophilus influenzae?

A

Haemophilus influenzae has a polysaccharide capsule that plays a crucial role in its virulence and pathogenicity.

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11
Q

How many serotypes of Haemophilus influenzae are there, and what are they based on?

A

There are six serotypes associated with invasive diseases. These serotypes (a, b, c, d, e, or f) are based on differences in the sugar-alcohol phosphate complex within the capsule.

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12
Q

What is the composition of the capsule for Haemophilus influenzae?

A

The capsule is composed of a sugar-alcohol phosphate (polyribitol phosphate) complex

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13
Q

what are the common types of invasive diseases caused by h. infuezae

A
  1. Pneumoia
  2. Bloodstream infection
  3. Meningitis
  4. Epiglotittis (swelling of the throat)
  5. Cellulitis (skin infection)
  6. Infectious arthritis (inflammation of the joint)
    common cause of ear infections in children and bronchitis in adults
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14
Q

what is the sigificance/virulence factors of capsule on the body of influezae

A

capsule is for antiphagocytic (prevents the action of phagocytes)

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15
Q

what is the sigificance/virulence factors of igA protease

A

Cleaves IgA on mucosal surfaces

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16
Q

what is the sigificance/virulence factors of Lipid A in H. influezae

A

Affects ciliated respiratory epithelium cells

17
Q

what is the sigificance/virulence factors of pilli

A

for attachment

18
Q

How does Haemophilus influenzae enter the body?

A

It enters by the inhalation of airborne droplets, resulting in either asymptomatic colonization or infections such as otitis media, sinusitis, or pneumonia.

19
Q

What does Haemophilus influenzae degrade and what does this facilitate?

A

produces IgA protease that degrades secretory IgA, thus facilitating attachment to the respiratory mucosa.

20
Q

Can Haemophilus influenzae spread beyond the respiratory tract? If so, how?

A

Yes, it can spread beyond the respiratory tract by entering the bloodstream (bacteremia) and spreading to sites including meninges and joints.

21
Q

In which age group do most infections occur with this organism?

A

Most infections occur in children between 6 months and 5 years with a peak in the age group from 6 months to 1 year.

22
Q

mention of specific conditions caused by Haemophilus influenzae outside of colonization?

A

conditions mentioned include otitis media, sinusitis, pneumonia, bacteremia, meningitis, and joint infections.

23
Q

mention the clinical manifestations of haemophilus influezae

A
  1. Rapid onset and fever
  2. Headache
  3. Stiff neck, along with drowsiness
  4. Sinusitis and otitis media cause pain i the affected area
  5. Opacification of the infected sinus
  6. Redness with bulging of the tympanic membrane
24
Q

what is the mode of transmission

A
  1. Droplet infection and discharge from the upper respiratory tract during the infectious period
  2. it is infectious as long as the organism is present, even in the absence of nasal discharge
  3. It is noninfectios within 24 to 48 hours after the start of effective antibiotics
25
Q

what specimens are preferred for culturing haemophilus influezae

A
  1. CSF
  2. Blood
  3. Nasopharyngeal specimens
    *specimens should be cultured as soon as possible and not refregerated)
26
Q

What are the gram staining results for hemophilus influezae for (1)blood and (1)CSF

A
  1. H. influezae is a small non motile gram negative coccobacillus
  2. Long thread-like and pleomorphic forms may be seen in c.s.f. (with pus cells),
    or following culture
27
Q

mention 2 ways how can gram staining for haemophilus influezae be enhanced

A
  1. extending time for safranin to 2 minutes
  2. substituting carbol fuschin for safranin
28
Q

explain the morphology of coccobacillus bacteria on microscope

A

Under the microscope they appear as slightly compressed spheres or ovals

29
Q

What are culture characteristics for haemophilus influezae

A
  1. H. influenzae grows poorly anaerobically.
  2. Growth is best achieved in a moist carbon dioxide enriched atmosphere
  3. The temperature range of growth is 20–40 ºC with an optimum of 35–37ºC.
  4. Media used must contain haemin or other iron-containing porphyrin and nicotinamide adenine dinucleotide (NAD) or its phosphate (NADP
    ~Factor X used to produce essential respiratory enzymes such as cytochromes, catalase, and peroxidase.
    ~Factor V is used as an electron carrier in the organism’s oxidation-reduction system.
30
Q

explain the results of culture of haemophilus influezae on chocolate agar

A
  1. After overnight incubation at 35–37 ºC in a moist carbon dioxide atmosphere, capsulated H. influenzae strains produce mucoid colonies, 1.5 mm or more in
    diameter.
  2. Cultures have a distinctive smell
  3. Heating blood agar to 75 ºC inactivates serum NADase and releases extra factor V from the red cells.
  4. Addition of bacitracin (300 mg/litre) provides a selective medium to recover H. influenzae from sputum(not needed when culturing c.s.f. )
31
Q

biochemical reaction results of haemophilus influezae

A
  1. catalase +ve
  2. oxidase +ve
  3. reduces nitrite to nitrate
  4. ferment glucose and galactose
  5. cant ferment sucrose, lactose and mannitol
32
Q

treatments for haemophilus influezae

A
  1. Ceftriaxone
  2. Ampicillin
  3. use of corticosteroids to fight inflammation

Microbiology 1 (27 decks)

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