Neisseria Prt 2 Flashcards
Can be a commensal in the upper tract!
Carried asymptomatically in 5-10
_____of the population as normal flora in the pharynx and oropharynx.
N. Meningitidis
(30) %
Adolescents
Young adults, particularly military recruits.
T or F
N meningitidis
Humans are the only natural host!
True
Meningitidis
Transmission: Acquired through infected _____from individuals who are carriers and require close contact with a susceptible host.
respiratory droplets
Meningitidis
• Causative agent of: ____ and ____, and other invasive diseases.
• Recovered from ____ and ____due to oral-genital contact
Meningitis and meningococcemia
urogenital and rectal sites
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.
meningitis
Meningococcemia
Neisseria meningitidis:
Risk factors:
• Asplenic individuals
• Persons with complement deficiencies
• Active & Passive smoking
• Crowded living conditions
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.
splenic macrophages
• Persons with complement deficiencies -deficiencies in_______. These late complement components are critical in supporting complement-dependent
bactericidal activity against Neisseria species.
C5, C6, C7, C8
Neisseria meningitidis: Disease Association
• The main virulence factor:_______ that protects it from phagocytosis.
polysaccharide capsule
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
13
BCY
ABCY and W135
Neisseria meningitidis: Disease Association
Incubation:
1-10 days
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
Fulminant Meningococcemia
Meningitis
Meningococcemia
Sepsis (presence of N. meningitidis in the blood
Purpura
Petechial skin rash
Tachycardia (heart beat over 100 beats/min.
Hypotension
Thrombosis (Disseminated Intravascular
Coagulation)
• 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.
Waterhouse-Friderichsen Syndrome (WFS)
• 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.
Waterhouse-Friderichsen Syndrome (WFS)
Neisseria meningitidis: Laboratory Diagnosis
• Specimens are collected from:
• Inhibited by____
CSF
blood
nasopharyngeal swabs & aspirates
joint fluids
sputum
urogenital sites
SPS
Note: A_______ is done to determine the carrier status of asymptomatic individuals.
nasopharyngeal swab
Direct Microscopy
• Gram stained smears from specimens
• Expected findings:
intracellular & extracellular gram negative diplococci
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.
BAP
Enriched CAP with inhibitor (MTM or Martin-Lewis)
72hrs
N. meningitidis
Colonies are (4)
round, smooth, glistening, and gray
N. meningitidis
- due to the presence of a polysaccharide capsule on the surface of the bacterium.
• Mucoid colonies
Neisseria meningitidis: Laboratory Diagnosis
Identification
• Indirect Microscopy:
• Presumptive test:
gram negative diplococci with adjacent ends
Oxidase
Neisseria meningitidis: Laboratory Diagnosis
Identification
• Definitive test:
• N.meningitidis utilize____
CHO utilization using СТА
glucose maltose
Algorithm for Laboratory Identification
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
N. cinerea
N. flavescence
N. lactamica
Resembling Organism???
N.gonorrheae
N.cinerea
N.meningitidis
Commonalities
• Glucose utilization in commercial methods
• Similarities with T3 colonies
Differential characteristics
• Colistin suscepbity
• Growth on SBA or CAP at
N.cinerea - N.gonorrheae
Commonalities
• Asaccharolytic reactions on CTA
Differential characteristics
• Growth on SBA or CAP at
22°C with yellow colonies
N. flavescence - N.cinerea
Commonalities
: Glucose & Maltose
: Athough it can ferment lactose,
but delayed
Differential
ONPG test
N. lactamica - N. meningitidis
Commonalities
Similar CHO utilization pattern
Differential characteristics
Reduction of nitrite to nitrogen gas
N.mucosa
N.Sicca & N.subflava
biovar perflava
Commonalities
Glucose & Maltose utilization
Differential characteristics
Growth on NA and production of polysaccharides from 1% or 5% sucrose
N. polysaccharea
N.meningitidis
