Intro to medical microbiology Flashcards
What are the three domains of life?
bacteria (prokaryote)
archea (prokaroyte)
eucarya (eukaryote)
What are the microbial causes of infection?
bacteria -prokaryotic
viruses- unclassified
fungi -eukaryotic
parasites - eukaryotic (usually but can be vector for prokaryotes)
prions (proteins)- unclassified
What is a bacterium?
Chiefly round, spiral or rod shaped single celled prokaryotic organism that typically
lives in soil, water, organic matter or the bodies of plants and animals
What is a virus?
A unique, acellular, metabolically inert organism that only replicate within living cells
What is a fungus?
Any of a kingdom of saprophytic and parasitic spore-producing eukaryotic typically
filamentous organisms including moulds, yeasts, mushrooms and yeasts
What is a parasite?
An organism living in, with or on another organism
What is a prion?
Protein of unknown function that resides on the surface of brain cells. An abnormal form of
prion protein that in mammals includes pathogenic forms that arise spontaneously (e.g. genetic
mutation) or transmission (e.g. via infected tissue) and upon accumulation in the brain cause a prion
disease e.g. BSE or CJD.
Rank the sizes of microbes?
Parasites - microscopic to over 30 m
* Fungi - 2 to 10 µm
* Bacteria - 0.2 to 0.5 µm
* Viruses - 20 to 400 nm
* Prions - 10 nm (often measured in Angstrom [1 A = 0.1 nm]
What is the difference between sterile and non sterile body sites?
STERILE
Brain
Heart
Liver
Kidney
NON-STERILE
Mouth
Oesophagus
Lungs
Stomach
Intestine
What are the common specimen types for bacterial culture?
- Mid stream specimen of urine (MSSU) – urinary tract infection.
- Sputum – lower respiratory tract infection.
- Throat swab – tonsillitis / pharyngitis.
- Swabs – wound infection, genital tract infection.
- Faeces – infectious diarrhea.
- Blood culture – septicaemia (sepsis).
- Cerebrospinal fluid CSF) – meningitis.
- Aspirate of pus – abscess.
- Bone – osteomyelitis.
What does staining specimen under microscope do?
Gives you good idea of morphology of microorgansim
What do lots of white blood cells tell us?
Common meningitis symptom
Lymphocitic- bowel
polymorphs- bacterial
How can diff parasites be differentiated ?
according to size
How do you interpret results?
- Knowledge of commensal flora (if applicable).
- Knowledge of common pathogens.
- Clinical significance?
if YES, antimicrobial susceptibility testing performed. - Some bacteria e.g. S. aureus are both a commensal (harmless) and
pathogen! - Final report with interpretive comments and results.
What are some multi-drug resistant organisms?
MRSA
VRE
ESBL
CPE
