Gram Negative Cocci Flashcards
What are characteristics of the Neisseria spp.?
Gram-negative cocci Oxidase positive Coffee bean or Kidney-shape appearance Non-motile Non-spore forming Gram stain red Primarily aerobic (with some facultative anaerobes) Often diplococcus
What are the 2 principal Neisseria pathogens?
N. gonorrhoeae
N. meningitidis
Do not survive well in the environment
What are 4 additional Neisseria species typically associated with respiratory and intestinal tract?
N. lactamica N. sicca N. subflava N. mucosa These may cause infections in the immunocompromised host
Describe Moraxella catarrhalis
Gram-negative aerobic oxidase positive diplococcus Respiratory tract pathogen
What is a fastidious organism?
Very particular food needs
Describe how Neisseria are identified in the lab
Require special media and growth conditions (temperatures)
Ability to produce acid from different sugars
Which two gram-negative organisms appear identical on a gram stain?
N. meningitidis and gonorrhoeae
What makes the serogroups for meningitidis?
Carbohydrates in the cell wall structure
Examples of N. meningitidis serogroups
A, B, C, D, X, Y, Z, W135
B & C most common in N. America
What are the 3 most common N. meningitidis serogroups?
B,C & Y
Which N. meningitidis serogroup has been associated with endemic disease in Canada?
C
Sub-groups have of C have been identified and are problematic
Where is the reservoir for N. meningitidis in the body?
nasopharynx
How does N. meningitidis spread?
Airborne droplets
Bacteria enter the bloodstream after crossing mucous barriers
Bloodborne infection is then carried to nervous system
Which antibiotic are most meningococci susceptible to?
Penicillin
Vaccines are available for which meningitis serogroups?
A, B, C, Y, W-135
Moraxella catarrhalis is a normal flora of which body part?
nasopharynx and oral
Typically does not represent infection of respiratory tract
When is Moraxella catarrhalis the most prolific?
When a concurrent virus is present.
Can then cause infection of middle ear, sinuses, or lower respiratory tract
(systemic infections rare)
Describe the Moraxella catarrhalis bacteria
Gram negative coccus
Indistinguishable from other Neisseria species
Define meningitis
Inflammation of the meninges (intact brain function)
What group of symptoms indicate meningitis?
headache, fever and neck stiffness (nuchal rigidity)
The CSF profile of meningitis would show alterations in these 3 things:
Presence of WBCs
Protein (elevated)
Glucose (low)
Two antibiotics typically prescribed for meningitis are:
ceftriaxone
vancomycin
(ampicillin - added in elderly population to cover for Listeria monocytogenes)
What are the additional precaution requirements for meningitis?
Contact & droplet until 24hrs of effective antimicrobial coverage has elapsed.
What is encephalitis?
inflammation of the brain parenchyma (abnormality in brain function)
Most of the WBCs in the CSF of someone with meningitis are:
neutrophils
Which Gram positive cocci is most likely to cause meningitis in a 2 DAY old?
Group B Streptococci (GBS)
Which Gram negative bacilli is most likely to cause meningitis in a 2 DAY old?
E. coli
Which Gram negative bacilli is most likely to cause meningitis in a 2 YEAR old?
Haemophilus influenzae
CSF for meningitis showing gram-positive diplococci is most likely to be which organism?
Streptococcus pneumoniae
CSF for meningitis showing gram-positive bacilli is most likely to be which organism?
Listeria monocytogens
Which AP are required for meningococcal meningitis and for how long?
Droplet; until 24 hrs after effective treatment initiated and symptom improvement
Describe haemophilus influenza type b meningitis
Uncommon in adults (due to vaccination Hib)
Usually accompanied by rash
Increased infection risk to children who are close contacts
NOT an increased risk of infection to adults who are close contacts
Prophylaxis for haemophilus influenza type b meningitis in adults and children over 4 is:
Rifampin, for close contacts
Haemophilus influenza type b meningitis is typically treated with which antibiotics?
ceftriaxone or cefotaxime
