Health and community antimicrobial and emerging diseases Flashcards
Causes for emerging infections
- Increased susceptibility
- Climate change and altered vector EIP
- Reemergence or better detection
- Changing modes of travel
- Urbanisation
- Resistance to biocides and antibiotics
Give examples of emerging infectious diseases
Shiga toxin producing E.coli
Cholera
Shigella spp.
Environmental causes of emerging diseases
- Dams: creates a large breeding site due to freestanding water
- Irrigation systems: crops bring people and sustain more people (increased s) and water is a breeding ground
How does urbanisation effect infectious diseases
- Increase population density (increase s)
- Changes in human contact patterns (increases S)
- Changes in vector breeding sites (increases S)
- Sanitation and access to clean water (reduces S)
- Access to health services (reduces S; increases R)
How does urbanisation affect transmission of certain disease
- Decreases oral faecal, cholera (better health care and sanitation)
- Increases respiratory, measles (Increased pop. high s, short cycles)
- Increases sexual transmission, HIV (More young males, change in sexual activity)
- Decreases blood borne, Malaria (Lower EIR, pollution and education and prevention approaches)
Cholera
-Gram negative, comma shaped rod
-Transmission: contaminated water (and food)
-Diarrhoea, cholera toxin causes Cl- ions to be excreted from cells of the intestine and reduces the re-absorption of NaCl
Osmotic pressure draws water into the lumen of the gut which manifests as watery diarrhoea
-There is a vaccine, treated by hydration therapy
Shigga toxin E.coli
- Gram negative, rod shaped
- Enterohemorrhagic or enterotoxigenic
- Causes bloody diarrhoea, vommiting, destroys red blood cells blocking kidneys
- Transmitted by contaminated water (and food)
- Hydration therapy
Antibiotic
A low molecular substance produced by a microorganism that at low conc. inhibits or kills other microorganisms
Antimcrobial
Natural, semi synthetic or synthetic substance that kills or inhibits the growth of a microorganism but causes little damage to the host
Different types of antimicrobial
- Plant based (essential oils)
- Metal based (silver, inhibits respiration and proteins)
- Nanotechnology
- Animal (L amino acid oxidases causing cell death)
- Microbe (Nissin)
How do antibiotics kill microorganisms
- Inhibition of DNA synthesis
- Inhibition of cell wall synthesis
- Inhibition of protein synthesis
Inhibition of DNA synthesis quinolones
- Binds to topoisomerases required for DNA unwinding
- Converts gyrases and topoisomerases IV into toxic enzyme that fragment the bacterial chromosome
3 methods for quinolone resistance
- Target mediated resistance: Mutations weaken quinolone enzyme interactions
- Plasmid mediated resistance: Decreases topoisomerase DNA binding and the amount of quinolones that can bind.
- Chromosome mediated resistance: Downregulate porins, upregulate efflux pumps
Inhibition of cell wall synthesis Beta lactams
Bind to penicillin binding proteins on maturing peptidoglycan strands and decrease synthesis while increasing autolysins leading to lysis and cell death
Inhibition of protein synthesis
30s inhibitors and 50s inhibitors
Aminoglycosides
Binds to the 30s subunit and causes proteins to misfold. Misfolded membrane proteins take up drugs more readily.
Also Leads to a redox response arc which alters metabolism and membrane potential, forming lethal hydroxyl radicals
Gram positive targeting bacteriocins
Class 1:
-Inhibits lipid II on the cell membrane, inhibiting peptidoglycan synthesis resulting in pore formation
Class 2:
-Binds to pore forming receptors and a pore is formed
Gram negative targeting bacteriocins
- Inhibition of DNA gyrase
- Inhibition of RNA ploymerase
- Inhibition of Asp-tRNA
Biofilms
Assemblage of bacterial cells associated with a surface and enclosed in an extracellular matrix. Becomes tolerant to antibiotics.
Multidrug resistant Klebsiella pneumoniae
- Destructive changes to human lungs, inflammation, haemorrhage that can produce a thick bloody sputum
- Rapid spread in south east europe in italy, slovenia and greece
- High in Greece as you dont need to be subscribed the antibiotic
Antibiotic resistance driven by humans
Farming practices Horicultural practices Veterinary practices Healthcare practices Irresponsible dumping
Typing methods
- Biotyping: growth profiles and metabolic activity
- Serotyping: antibody strain discrimination
- Antityping: antibiotic resistance strain discrimination
- Phage typing: bactiophage resistance strain
How was Psuedomonas aeruginosan typed and what where the results
Biotyped: Gram negative Bacilli Lactose - oxidase +
DNA gel electrophoresis
What is pulse field gel electrophoresis
Has an alternating voltage gradient, switches 3 directions. Seperates larger molecules of DNA
