Flashcards in Neisseria and Haemophilus Deck (15)
What is the only genus of gram negative cocci that frequently causes disease?
Is neisseria motile or non-motile
Describe the oxygen requirements of Neisseria
Neisseria is an aerobe
Is Neisseria an obligate or opportunistic human pathogen?
Describe the difference in the virulence of N. meningococcus and N. gonococcus
-N. Meningococcus has a large capsule
-N. gonococcus has no capsule but strong adhesins and phase/antigenic variation
What are the 4 major reasons that N. gonoccoi is so infectious?
1. Shed in genital secretions (although not motile)
2. Can enter epithelial cells
3. Extracellular protesase cleave IgA1
4. Uses host-derived antigens as camoflage
Is Haemophilus gram positive or negative? What is its shape?
Small Gram-Negative coccobacilli
What is the oxygen requirement for Haemophilus?
Where in the human body does Heamophilus reside?
Colonizes the upper respiratory tract of almost everyone
What 2 things does H. Influenzae need for growth?
1. NAD+ and hemin (X factor) which requires lysed blood (chocolate agar)
2. Need capsule to be virulent
What are the 4 Virulence Factors for Haemophilus?
1. Polyribosyl ribitol phosphate capsule
2. Endotoxin (causes pathogen-directed endocytosis)
3. IgA1 protesase (just like Neisseria gon.)
4. Pili and OM proteins (like N. gonoccocus)
How can you prevent an infection by Neisseria?
1. Behavioral (condoms, early diagnosis/treatment)
2. Vaccines (difficult to make tho)
a) Quadrivalent (MPSV4) derived against capsular polysaccharide from 4 serotypes
b) Tetravalent (MCV4) which is a polysaccharide-protein conjugate (children t respond well)
How do Psedumonas adhere?
Mediated by flagella and pili
-interactions with glycolipid (cleaves sialic acid to create asialo GM1; receptor for type 4 pili) on host cells and also TLR5
....basically they cleave a glycolipid to create their own receptor for a pili
Why are people with cystic fibrosis the most likely to get infected by P. aeruginosa?
1. They have decreased sialylation of surface glycolipids (bacteria binds to these asialo-glycolipids)
2. Dehydration of respiratory secretions (impairs mucocilary system)
3. Mucoid expopolysaccaride shields organism from immune system