Infections Of The CNS: Bacteria And Fungi Flashcards
Outline neisseria meningitdis
-gram-negative diplococci
-polysaccharide capsule, antigenic, used for serotyping
-carried asymptomatically by 20% of the population, spread by droplets
-invasion poorly understood
Name virulence factors
-capsule
-IgA protease
-pili
-endotoxin
-outer membrane proteins
Outline the capsule in virulence factors
Polysaccharide capsule
Essential for survival in bloodstream
Inhibits invasion and adhesion
Outline IgA protease in virulence factors
Cleaves the hinge region in IgA1
Creates immunologically inactive Fc and Fab fragments
Outline pili in virulence factors
Type IV pili extend past the capsule
Attach cells to the host surface
Outline endotoxins in virulence factors
LOS endotoxin
Released in outer membrane blebs
Diffuse vascular damage largely attributed to the action of the LOS endotoxin
Outline outer membrane proteins in virulence factors
Opa and opc
Bind to host CEACAM receptor family, as well, ECM fibronectin and/or vitronectin
What is B serogroup
A(-8) linked sialic acid homopolymer identical structure to human feral neural cell-adhesion molecule (NCAM)
Instead use outer membrane vesicles
Outline neisseria gonorrhoeal
-typically effects genitals
-can get extragenital infection in pharynx and rectum
-untreated can cause disseminated infection
-antibiotic resistance is becoming more of a problem but can treat with antibiotics
Outline cryptococcus neoformans
has tropism for CNS- travel form lungs to brain
Effects patients with depressed cell-mediated immunity
Slow on-set (days to weeks)
Treat with combination of amphotericin B and flucytosine
Outline Lyme disease
Bacterial disease
Vector borne in black legged ticks
Nymph stage transmits infection
Outline the early disease stage of Lyme disease
Erythema migrants (bullseye rash)- bacteria multiply locally
Approx 1 week, up to 3 months after bite
In 50% of patients fresh transient lesions at other sites too
Find IgM in patient serum
Outline further Lyme disease stage
Immune reactions- antibodies and T cells
75% of people develop further disease
1 week to over 2 years from initial onset
What can Lyme disease bacteria cause
Cranial nerve involvement
Peripheral nerve involvement
CNS involvement- Brain legions and meningitis
What bacteria causes syphilis
Treponema pallidum
What happens at the point of infection from syphilis
Bacteria grows at site of infection and disseminates throughout the body
Sexually transmitted, risk reduced by barrier contraception
How can you treat syphillis
Penicillin
Where is tetanus found
Found in rusty nails and dirt
Outline clostridium tetani and botulinum
Gram negative bacilli
Anaerobic
Form sports- to persist in harsh environments
-Tetani- end of cell (tennis racket), locked paralysis
-botulinum- middle of cell, floppy paralysis
Treat with antitoxin and prevent with toxoid vaccine
Outline characteristics of TeNT
Inoculated from non-sterile wound
Blocks inhibitory mediators in spinal synapses
Overactivity of motor neurones and SNS
Muscle spasms, lock jaw, tachycardia
Outline characteristics of BoNT
Ingested and absorbed from gut
Acts on PNS by blocking release of acetylcholine
Effects motor and autonomic NS
Weakness and paralysis
Outline staphylococcus aureus
Gram-positive cocci
Normal part of flora but also able to cause of a variety of infections - opportunistic pathogen
Common cause of skin and soft tissue infection
What is ophiocordyceps unilateralis
Zombie-ant fungus
