Medical Microbiology

Question 1

methods of transmission

Answer 1

• direct contact: touching contaminated person or spreading via physical contact (STI)
• indirect contact: transmission via dropelts , vectors (living organisms like tiks), soil, food or water

Question 2

what are methods of prevention

Answer 2

• transmission can occur by touching inanimate objects: can sterilize to kill all pathogens or disinfection killing some but not all microbes present
• methods sterilization= extreame heat, radiation, ethylene gas
• methods of disinfection = microwaves, pasteurization or chemicals (alcohols, halogens or hydrogen peroxide)
• pathogens on living tissue can be killed by antiseptics

Question 3

breifly explain immunization

Answer 3

• after transmission a strong immune response can fight off pathogen before damage occurs
• can occur faster if memory T and B cells are present
• experiencing an infection once generally gives host natural active immunity
• host does not experience infection again as long as memory cells present

Question 4

how does vaccine cause immunity

Answer 4

• required bc initial disease state too seveere or long lasting for antural process to be useful
• attenuated (weakened) or dead pathogen or fragment of it is injected as a vaccine
• injected microbe still causes an immune response including the formation of memory cells but disease not aquired

Question 5

what is passive immunity

Answer 5

• acquired through direct transmisssion of antibodies from one source to another
• allows individual to fight off infection by pathogen specific to antibodies
• antibody is eventually broken down by the body -> immunity if lose bc no membory B cells present to create new antibodies
• most often from mother to fetus via placenta or through breast milk but can be aquired through clinical injection

Question 6

what is an antibacterial

Answer 6

• work specifcially on bacteria
• can be specific to gram pos or gram negative
• Bactericidal agents kill bacteria
• Bacteriostatic agents stop bacteria from dividing: depends on patient having a functioning immune system to eliminate the bacteria after reproduction is stopped (not often used in immunicomprimised patients)

Question 7

bacterial resistance

Answer 7

• • towards antibacterial agents
• includes pumping out the antibiotic, producing enzymes that inactivate the antibiotic, mutating DNA to make them immune to effect of antibiotic

Question 8

what is an antiviral

Answer 8

• work specifically on viruses whicha re omre difficult to treat
• viruses are contained in host cells so to treat virus must damage or destroy host cell as well
• focus on preventation
• can be developed to interfere with a virus’ ability to penetrate cells or replicate its genetic material
• can provide faulty nucleotides (nucleoide reverse trancriptase inhibitors): interferes with proper DNA replication
• disables protease (enzyme req for DNA replication and viral reproduction

*do not eliminate infection completely but cna keep the infection to a minimum

Question 9

what are antifungals

Answer 9

• most capitalize on the difference between a microorganism’s cells and eukaryotic human cells
  ex: contain cell wall so can function by destroying that

ex = fluconazole which prevents the conversion of an ergosterol precursor to ergosterol itself, ergosterol is essential component of cell membrane of the fungus but is not present in human cells

Question 10

what are antiparasitics

Answer 10

• work to destroy parasite w/o destroying host

Question 11

explain resistance

Answer 11

• occurs within microbes after extended exposure to a particular antimicrobial
• some organisms are inherently resistance to certain antimicrobials or have mutations to make them resistant
• resistance often comes by natural selection, only resistance bacteria replicate causing future members to exhibit resistance
• as more antibiotics discovered and used inc resistance
• staring to avoid use of broad spectrum antimicrobials