Neisseria Flashcards
What are the two types of Neisseria and what do they each cause?
Neisseria meningitidis causes meningococcal meningitis
Neisseria gonorrhoeae causes gonorrhea
Describe the morphology of Neisseria. What is unique about this bug?
Gram negative diploccoi (kidney beanzzz).
It is unique because it is the only pathogen that is a gram negative coccus
What are the growth requirements of neisseria?
Pathogenic types require blood products. 5-10% CO2 is also reqd
What would you grow neisseria on?
Thayer-martin selective medium. It has chocolate agar, vancomycin (to inhibit gram +), polymyxin E (gram negative enterics) and nystatin (antifungal)
Is there an animal reservoir for neisseria
No. Only humans.
Is neisseria oxidase positive or negative?
oxidase positive
What does Neisseria secrete?
IgA protease
What does Neisseria have instead of LPS?
LOS (lipo-oligosaccharide?)
How would you distinguish Neisseria gonorrhoeae from Neisseria meningitidis from Neisseria Lactamica (nonpathogenic)?
Gonorrhea ferments only glucose, does NOT ferment maltose, lactose or sucrose.
Meningitidis ferments glucose AND maltose
Lactamica ferments glucose, maltose, and lactose
Meningococcus: What will it cause?
Severe CNS infection or septicemia
Meningococcus: Where do these cells multiply?
Outside of cells, but can be seen inside phagocytes
Where does meningococcus first colonize?
Nasopharynx
Does meningococcus have a capsule?
Yes. Gives rise to smooth colonies and common serogroups A, B, and C
What is the incubation period for meningitis?
days and up to a week
Which individuals are most at risk for neisseria meningitiditis?
Children under 5, with a large peak in children under 1 year of age
What is the waterhouse-friderichsen syndrome?
Rare adrenal failure resulting from meningitis
How would you diagnose N meningitidis?
Symptoms: Upper respiratory infection followed by meningitis. Petechiae. culture. Latex agglutination for capsule antigen in CSF
How would you treat N meningitidis?
Ceftriaxone (3rd generation)
Penicillin
Cipro
Rifampin
Is there a vaccine for N Meningitidis?
Yes. GRPS A, C, Y, W-135
What causes meningitis in children under 2 months?
E coli K1
What causes meningitis in children under 5 years?
Haemophilus influenzae
Which type of bacterial meningitis affects individuals between 2 months-34 years?
Neisseria meningitidis, streptococcus pneumoniae, listeria monocytogenes
What does N. meningitidis grow on?
Chocolate agar and blood agar
How would you distinguish N meningitidis and S pneumoniae?
N. meningitidis is gram negative while S pneumoniae is gram positive. Both are diplococci which grow on CAP and BAP
Does N gonococcus have a capsule?
No.
Is the endotoxin released by N gonococcus significant?
No.
How would you diagnose gonococcus?
visualize in gram stain of pus
What is caused by disseminated gonococcus?
arthritis-dermatitis syndrome and pelvic inflammatory disease
Are N gonococcus intracellular or extracellular?
Intracellular gram negative diplococci. This is the key to a positive diagnosis
If gonorrhea is passed to the infant from the mother, where will the infection be localized?
Usually to the conjunctiva. Could also cause pneumonia
Describe the pathogenesis of gonococcal infection
- gonococcus attaches to epithelial cell using pili
- Endocytosis into epithelial cell
- Intracellular multiplication. Crowding can cause expulsion of ciliated cells from mucosa during infection
- Exocytosis into the tissue
What kind of gonococci do neisseria gonorrheae have?
Type 4 pili, but there are many antigenic variants of this
Describe the difference between phase variation and antigenic variation?
Phase variation= On or Off switch. Antigenic variation= A number of antigens could be expressed.
How would you diagnose N gonorrhoeae?
Clinical history + gram stain + culture for oxidase positivity/growth on media
How would you treat gonorrhea?
Ceftriaxone
Are there any vaccines for gonorrhea?
No. Because there is a lot of antigenic variation
