unit 4 Flashcards
. is Bacteria : Gram positive or gram negitive
both
Cocci
Gram positive and gram negative
Bacilli
Either Gram positive and gram negative
Helminths
multicellular microorganisms parasitic worms, larvae, and arthropods living On the body
Prions
: are small abnormally folded proteins that
cause infections
Prokaryotic cells
bactira
Eukaryotic cells
Fungus
◦ Protozoa
◦ Helminths
Higher life forms, plants, animals, and humans are eukaryotes
Prokaryotic cells weakneeses
Antibiotics
Eukaryotic cells weakness
Diseases caused by these organisms are very difficult to treat
Stain with crystal violet
Treat with iodine * Treat with decolourizing
alcohol
Gram Stains Purpose
First step towards identifying unknown
bacteria
The difference between gram-negative and grampositive
bacteria can be important when determining
appropriate treatment for an infection.
Microbiological Culture Media
Gels or Broths
* Promote Growth of organisms
* Bring out characteristics to aid in identification
Selective
growth a specific organisms
Differential
contains specific ingredients to distinguish
between closely related organisms
- Enriched media
– additional nutrients supports the
growth of a range of organisms
Transport media
purpose is to keep the organisms
alive during transport for testing
Cocci Bacteria
Spherical * Irregular clusters * Chains * Diplococci (pairs) * sets of four (tetrads)
Staphylococci
gram-positive spherical cocci Most common cause of wound infections
Staphylococcus aureus eye infections include:
Blepharitis
* Chalazion
* Staph marginal ulcers
* Meibomitis
Neisseriaceae:
Bean shaped gram negative diplococci
* Preference for mucous membranes
* Can invade intact tissue
Neisseria gonorrhoeae
causative agent of gonorrhea
* Severe and damaging conjunctivitis
Propionibacterium acnes
adult skin and conjunctiva, living off the sebum
and oil produced in sebaceous glands.
where Haemophilus influenza
childhood eye infections
Spiral Bacteria
Corkscrew shape * Ability to penetrate into tissue
Fusarium Solani
Aspergillus
abundant in soil and plant material ◦ traumatic keratitis and corneal ulcer.
Eukaryotic unicellular organisms
transmitted by contaminated food and water ◦ insect bites
Acanthamoebic keratitis
Serious corneal infection * Difficult to treat * Can result in blindness. * Contact lens wear is a risk factor
Toxocara
ngestion of larvae in dog or cat feces
* Toxocariasis is caused by the migration of the
larvae into the eye
Strand of DNA or RNA surrounded by a protein coat
Can only reproduce if they infect a cell.
