(M) Lesson 7.4: Gram Positive and Gram Negative Cocci Flashcards
Gram-Negative Cocci
- Usually in pairs or in singly
- Genera (included in the exceptions for Gram positive cocci bacteria - Neisseria, Moraxella, Veilonella)
Gram-Negative Cocci
- G(-) diplococci w/ flattened sides
- Oxidase (+)
- Glucose (+)
Neisseria
Two medically important Neisseria genera?
- N. meningitidis
- N. gonorrhoeae
How are the Neisseria genera differentiated?
Carbohydrate fermentation assay
Study the Meningitidis and Gonorrhoeae table
GO BROOO
- G(-) kidney bean-shaped diplococci
- Large capsule
- Grows on CAP and BAP in 5-10% CO2
- Ferments maltose
- Oxidase (+)
- 13 serogroups: A, B, C, D, 29E, H, I, K, L, X, Y, Z, W-135
Neisseria meningitidis (Meningococcus)
One important thing to know when you are using CAP or even BAP if you are growing N. meningitidis, you need to grow them in a?
Candle jar
Reservoir for Neisseria meningitidis?
Human nasopharyngeal area
Less than or equal to 5% are carriers which are asymptomatic
Transmission for Neisseria meningitidis?
- Respiratory droplets
- Oropharyngeal colonization
- Spread to the meninges via the bloodstream
- Disease occurs only in small percent of colonized individuals
Identify the pathogenesis (N. meningitidis)
Most important
Polysaccharide capsule
Identify the pathogenesis (N. meningitidis)
For oropharynx colonization
IgA protease
Identify the pathogenesis (N. meningitidis)
Causes fever, septic shock in meningococcemia, overproduction of outer membrane
Endotoxin (lipopolysaccharides [LPS])
Identify the pathogenesis (N. meningitidis)
To colonize and invade
Pili and outer membrane proteins
Predisposing factors of N. meningitidis
Deficiency in late complement components (C5 to 8) predisposes of bacteremia
N. meningitidis
Infected patient experiences fever, vomiting, rashes, body pain
Meningitis
N. meningitidis
Happens if only meningococcus spreads in larger numbers reaching the bloodstream, even causing hematoma
Meningococcemia
Most severe form of meningococcemia
Waterhouse-Friderichsen Syndrome
Specimen for lab diagnosis of N. meningitidis?
- Blood for culture
- CSF smear hen culture
- Petechial aspirate
T or F: N. meningitidis is gram negative cocci is on CSF smear
T
N. meningitidis is confirmed using what test?
Carbohydrate fermentation test
Treatment for N. meningitidis?
- Penincillin G
- Cetfriaxione
- Beta-lactamase production
Prevention for N. meningitidis?
Vaccine for capsular polysaccharides of strains: A, C, Y, W-135