Infections Flashcards
What are the characteristics of Gram negative bacteria?
- They have a cell wall
- Have a low amount of peptidoglycan
- Not sensitive against penicillin or lysozyme
- Are sensitive against mechanical pressure
e.g. E.coli
What are the characteristics of Gram positive bacteria?
- Have a cell wall
- High amount of peptidoglycan
- Sensitive against penicillin lysozyme
- Not sensitive against mechanical pressure
E.g. Bacillus anthracis
What is venereal transmission?
Skin to skin contact in the genital area- STDs
How does vector transmission occur?
Bites via an infected vector e.g mosquito
How does vertebrate reservoir transmission occur?
Via contact with animals e.g dogs
How does vector-vertebrate reservoir transmission occur?
When an insect/vector infects an animal and then the animal infect us
What are some examples of diseases transmitted via a vector?
Malaria
Sandfly fever
Typhus
What are some examples of diseases transmitted via a vertebrate reservoir?
Rabies
What are some examples of diseases transmitted via vector-vertebrate transmission?
Plague
Yellow fever
What is horizontal transmission?
Humans infecting the community via air, water, food etc
What is vertical transmission?
Infecting others through generations e.g. milk, placenta
What causes borrelia burgdorferi?
Ticks
What can aborrelia burgdorferi infection lead to?
Lyme disease
How can pneumonia be acquired?
Community or hospital
What bacteria is the largest cause of community and hospital acquired UTIs?
E.coli
Community- 80%
Hospital- 40%
What does bacillus anthracis cause?
Anthrax
What does bacillus cereus cause?
Food poisoning
How can cholera be transmitted?
Drinking contaminated water
improperly cooked seafood
What are the symptoms of cholera?
Diarrhoea
Abdomincal cramps
Nausea
Vomiting
Dehydration
What usually5 leads to a cholera outbreak?
A natural disaster as there is a disruption of sanitation in most cases.
What bacteria causes cholera?
Vibrio Cholerae
What is the mechanism of action of cholera?
- The vibrio cholerae bacterium produces a cholera toxin
- This cholera toxin binds to GM1 (Ganglioside receptor) receptors in the GI tract
- A subunit of the toxin, enters the epithelial cell and binds to and activates the G-alpha-s subunit
- The g-alpha-s subunit activates adenyl cyclase
- Adenyl cyclase produces cAMP which activates the CFTR (Cystis fibrosis transmembrane conductance regulator)
- This leads to an efflux of Cl- ions out of ht expel and into the lumen of the GI tract. As Cl- leaves it also causes an efflux of Na+ and H20 into the lumen.
- This movement of water leads to watery diarrhoea
Name two pyogenic cocci bacteria?
- Staphylococcus aureus
- Methicilin resistant Staphylococcus aureus (MRSA)
What can be used to treat MRSA?
Vancomycin
What can Clostridium petani cause?
Tetanus
What can clostridium perfringens cause?
Food poisoning, wound infection and gangrene
What can clostridium difficile cause?
Sever colitis (inflammation of the colon and rectum)