Chapter 7 Flashcards
What are microbes/microorganisms?
Tiny life forms. Include procaryotes, eukaryotes, and viruses. Some convert matter to simpler forms through decay, some take inorganic compounds and convert them to higher forms.
How much of organic matter do microbes account for on the planet?
60 percent
What are indigenous microflora?
Microbes that are harmless under normal circumstances but can become pathogens when they enter the body through a surgical or traumatic wound. (aka opportunistic pathogens).
What is symbiosis?
Refers to both organisms and can be harmful, beneficial, or harmless. Three categories: mutualism, commensalism, and parasitism.
What is mutualism?
Both organisms benefit and depend on each other to a certain extent.
What is commensalism?
One organism benefits and the second is unharmed/unaffected.
What is parasitism?
One organism benefits and the host is harmed.
What is infection?
Multiplication of organisms in the tissues of a host
What is a nosocomial infection (HAI)?
Infection that is developed in a healthcare setting.
Which pathogen is most commonly associated with surgical site infections (SSI)?
Staphylococcus aureus, a gram-positive coccus. Responsible for 30 percent of SSI’s.
Where is Staphylococcus aureus found?
in the flora on the skin, hair, and nares. SSI’s can be caused by both surgical personnel and patient’s own skin.
What are some common bacterial pathogens and what are the infections they are associated with?
Add table later
What is tuberculosis (TB) and what are some precautions which should be taken with known carriers?
Caused by a bacteria called mycobacterium tuberculosis. Usually infects lungs but can infect kidneys, bones, joints, and skins. Elective operations are postponed until drug therapy is effective. Other procedures performed must implement isolation precautions (wearing gloves, eyewear, N-95 mask). Pt must also be informed on how they can prevent cross contamination.
What are viruses and what are some characteristics unique to them?
Nonliving particles that are reliant on the host.
-they are intracellular parasites
-viral replication depends on nucleic acid
-viral cells have RNA/DNA and protein coat that encases nucleic acid
-viral cells depend on protein production of host.
How does the virus enter the host cell?
- viral cell attaches to host with receptors on the capsomeres
- virus enters cell through membrane penetration or receptor mediated endocytosis
- viral replication begins
How do viruses enter the body?
-inhalation of droplets
-through bodily fluids
-ingestion of contaminated food/water
-bites by infected insects
What are some common viral pathogens and what are their methods of transmission?
HBV- body fluids
Hep C- blood
Hep D- body fluids
HIV- body fluids
HSV- fluid from lesions
papillomavirus- contact
cytomegalovirus- body fluids
Creutzfeldt-Jakob Disease (CJD)- unknown but thought to be through CSF. associated w contaminated instruments.
What causes microorganisms to be transmitted on a global basis more easily?
-globalization
-multi-drug-resistant organism (MDR’s)
-some diseases include dengue, ebola, marburg, and lassa
What are prions?
Short for proteinaceous infectious particle. They are nonliving strands of protein that do not have DNA/RNA. Responsible for transmissible spongiform encephalopathy (mad cow, CJD, scrapie)
How does CJD spread throughout the body?
Human body creates protein similar to a prion, called PrP. Responsible for CJD but the normal protein’s structure is different from infectious prion. The PrP changes from a noninfectious alpha-helical form, to the infectious beta-sheet. When a prion contacts normal PrP, it starts a chain reaction in which the prion is replicated by folding the alpha-helical protein into the pathogenic beta-sheet form inside the neurons of the central nervous system (CNS). The beta-sheet prions accumulate in the lysosomes and eventually kill the neuron. The death of the neurons creates holes in the brain tissue, which aids in the release of prions to further invade and infect healthy neurons.
How is CJD transmitted?
Through prion contaminated surgical instruments. Can also be inherited genetically or a sporadic case. Be extra careful of eye tissue, dura mater, brain tissue, and spinal cord.
What are some components of CJD?
-develops very slowly w incubation of 20 yrs
-early symptoms include memory loss and depression
-no vaccine or cure
-diagnosed through EEG or microscopic histology
-variant strand called vCJD or ncCJD has earlier median onset of 28 yrs old. duration of symptoms is longer at 13-14 months.
What are parasites?
Invertebrates that cause disease. Two categories: unicellular and multicellular protozoa.
What are helminths?
Part of the metazoan category. Are commonly known as worms. Primary route of transmission is ingestion of contaminated food and water but also includes penetration through skin, fecal-oral contamination, and arthropod bites. They can migrate outside the intestinal tract and cause issues in other tissues.
What are protozoa?
Unicellular eukaryotes responsible for causing diseases such as malaria and chronic sleeping sickness. Include amoebas, flagellates, ciliates, coccidia, and microsporidia. Transmitted through the fecal-oral route.
What is Entamoeba histolytica?
Protozoa that is responsible for amebic dysentery. Usually in pt’s undergoing a colonoscopy/sigmoidoscopy. Endoscope and other instrumentation should be thoroughly decontaminated.
What is Trichomonas vaginalis. T. vaginalis
A unicellular protozoa that will grow if vaginal/urethral acid levels are off and cause trichomoniasis which is usually and STD.
What are fungi?
eukaryotic organisms that are either unicellular yeasts or multicellular molds and mushrooms. reproduce both sexually and asexually. Majority are opportunistic pathogens that cause infection when host is immunocompromised. Common in HIV/AID’s patients.
