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Bacte LEC > Neisseria Prt 2 > Flashcards

Neisseria Prt 2 Flashcards

1
Q

Can be a commensal in the upper tract!

Carried asymptomatically in 5-10
_____of the population as normal flora in the pharynx and oropharynx.

A

N. Meningitidis

(30) %

Adolescents
Young adults, particularly military recruits.

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2
Q

T or F
N meningitidis

Humans are the only natural host!

A

True

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3
Q

Meningitidis

Transmission: Acquired through infected _____from individuals who are carriers and require close contact with a susceptible host.

A

respiratory droplets

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4
Q

Meningitidis

• Causative agent of: ____ and ____, and other invasive diseases.

• Recovered from ____ and ____due to oral-genital contact

A

Meningitis and meningococcemia

urogenital and rectal sites

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5
Q

Meningococcal_____ is an infection of the tissue (called the “meninges”) that surrounds the brain and spinal cord.

_____is an infection of the blood and may also involve other parts of the body.

A

meningitis

Meningococcemia

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6
Q

Neisseria meningitidis:

Risk factors:

A

• Asplenic individuals
• Persons with complement deficiencies
• Active & Passive smoking
• Crowded living conditions

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7
Q

Asplenic individuals - have increased susceptibility to encapsulated bacteria such as Neisseria meningitidis because they lack ______that filter and phagocytose bacteria. The spleen also plays a vital role in the immune response to encapsulated bacteria.

A

splenic macrophages

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8
Q

• Persons with complement deficiencies -deficiencies in_______. These late complement components are critical in supporting complement-dependent
bactericidal activity against Neisseria species.

A

C5, C6, C7, C8

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9
Q

Neisseria meningitidis: Disease Association
• The main virulence factor:_______ that protects it from phagocytosis.

A

polysaccharide capsule

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10
Q

Neisseria meningitidis: Disease Association

• Pathogenic strains:_____ serogroups based on antigenic variations of the capsule: A, B, C, D, H, I, K, L, X, Y, Z, 29E, and W135
•_____ - predominant in the U.S
•_________- occur worldwide

A

13

BCY

ABCY and W135

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11
Q

Neisseria meningitidis: Disease Association

Incubation:

A

1-10 days

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12
Q

Neisseria meningitidis: Disease Association

Adheres and colonizes the nasopharyngeal mucosa and enters the blood stream:
____________: Purpura (hemorrhaging of blood into the skin and mucous membranes producing bruises) with petechial skin rash (pinpoint red spot caused by hemorrhage)

______: Abrupt onset of frontal head ache, neck stiffness, confusion, and photophobia

A

Fulminant Meningococcemia

Meningitis

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13
Q

Meningococcemia

A

Sepsis (presence of N. meningitidis in the blood

Purpura

Petechial skin rash

Tachycardia (heart beat over 100 beats/min.

Hypotension

Thrombosis (Disseminated Intravascular
Coagulation)

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14
Q

• Hemorrhage in the adrenal gland
• Adrenal glands fail to function normally
• Results from the blood stream dissemination of N. meningitidis
• Occurs in pediatric population at infancy or childhood.

A

Waterhouse-Friderichsen Syndrome (WFS)

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15
Q

• Occurs in pediatric population at infancy or childhood.

Note: It is a pediatric emergency. Prognosis is poor and most of the time will result to death.

A

Waterhouse-Friderichsen Syndrome (WFS)

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16
Q

Neisseria meningitidis: Laboratory Diagnosis

• Specimens are collected from:

• Inhibited by____

A

CSF
blood
nasopharyngeal swabs & aspirates
joint fluids
sputum
urogenital sites

SPS

17
Q

Note: A_______ is done to determine the carrier status of asymptomatic individuals.

A

nasopharyngeal swab

18
Q

Direct Microscopy
• Gram stained smears from specimens
• Expected findings:

A

intracellular & extracellular gram negative diplococci

19
Q

Neisseria meningitidis: Laboratory Diagnosis
Culture & Incubation
• Cultured on_____ (primary medium)
• _______ can be used ( especially from specimens containing normal microbiota)
• Incubated in the same atmospheric conditions described for N. gonorrhoeae and examined daily for____ hours.

A

BAP

Enriched CAP with inhibitor (MTM or Martin-Lewis)

72hrs

20
Q

N. meningitidis

Colonies are (4)

A

round, smooth, glistening, and gray

21
Q

N. meningitidis

  • due to the presence of a polysaccharide capsule on the surface of the bacterium.
A

• Mucoid colonies

22
Q

Neisseria meningitidis: Laboratory Diagnosis

Identification
• Indirect Microscopy:
• Presumptive test:

A

gram negative diplococci with adjacent ends

Oxidase

23
Q

Neisseria meningitidis: Laboratory Diagnosis

Identification
• Definitive test:
• N.meningitidis utilize____

A

CHO utilization using СТА

glucose maltose

24
Q

Algorithm for Laboratory Identification

A

Direct Microscopy (Gram Staining)

Culture (BAP, Enriched CAP as Selective Media)

Colony morphology and Gram staining (indirect microscopy)

Presumptive Test (Oxidase) - presence of Neisseria

Definitive Test (CHO utilization) - Gonorrheae or Meningitidis

AST and Reporting

25
Q

N. cinerea
N. flavescence
N. lactamica

Resembling Organism???

A

N.gonorrheae
N.cinerea
N.meningitidis

26
Q

Commonalities
• Glucose utilization in commercial methods
• Similarities with T3 colonies

Differential characteristics
• Colistin suscepbity
• Growth on SBA or CAP at

A

N.cinerea - N.gonorrheae

27
Q

Commonalities
• Asaccharolytic reactions on CTA

Differential characteristics
• Growth on SBA or CAP at
22°C with yellow colonies

A

N. flavescence - N.cinerea

28
Q

Commonalities
: Glucose & Maltose
: Athough it can ferment lactose,
but delayed

Differential
ONPG test

A

N. lactamica - N. meningitidis

29
Q

Commonalities
Similar CHO utilization pattern

Differential characteristics
Reduction of nitrite to nitrogen gas

A

N.mucosa

N.Sicca & N.subflava
biovar perflava

30
Q

Commonalities
Glucose & Maltose utilization

Differential characteristics
Growth on NA and production of polysaccharides from 1% or 5% sucrose

A

N. polysaccharea

N.meningitidis

Bacte LEC (51 decks)

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