Gram (-) Cocci Flashcards
Oxidase positive encapsulated diplococci, growth on Chocolate agar, ferments glucose and maltose, transmitted by respiratory droplets
Neisseria meningitidis
Strain of N. meningitidis that is most common
B strain (NOTE: vaccine contains strains Y, W-135, C, and A. B strain is not immunogenic so no protection would be induced anyway)
Virulence factors of N. meningitidis?
Polysaccharide capsule (detect with latex particle agglutination)
IgA protease (allows colonization in pharynx)
Endotoxin (fever, septic shock)
Pili
Deficiency in late complement components (C5-C8) predisposes to bacteremia
What indicates that N. meningitidis infection has spread to blood? What are dangerous complications of fulminant cases of meningitis caused by N. meninigitidis?
- bacteremia indicated by rash
- Waterhouse-Friderichsen syndrome, DIC, shock, coma, death
What are the best ways to diagnose N. meningitidis?
Gram stain of CSF (look for G- diplococci), PCR, latex agglutination to detect capsule
Why are all infants born in the US given erythromycin ointment on their eyes?
Prevention of ophthalmia (N. gonorrhea infection that leads to blindness if untreated)
Oxidase positive diplococci, ferments flucose, growth on chocolate agar, sensitive to drying and cold, sexually transmitted disease
Neisseria gonorrhoeae
Which occurs more commonly, gonorrhea or chlamydia?
Chlamydia
What are the pathogenic factors of N. gonorrhoeae?
Pili (attachment), Opa (adherence), IgA protease, invasion of mucosal surfaces to cause inflammation
- all can undergo antigenic variation, which causes antibiotic resistance
Symptoms of a gonorrhea infection
Males: more likely to present, purulent urethral exudate
Females: more likely to be asymptomatic, endocervitis, PID, arthritis
Diplococcus, causes otitis media or sinusitis, normal flora of upper respiratory tract
Moraxella catarrhalis
Top 3 most common causes of otitis media
1) Streptococcus pneumoniae
2) Haemophilus influenzae
3) Moraxella catarrhalis
