Introduction to Medical Microbiology Flashcards
What are the 5 possible infecting agents?
Bacteria
Viruses
Fungi
Parasites
Prions
What is the specimen collection for a urinary tract infection?
Mid stream urine
What is the specimen collection for a chest infection?
sputum
What is the specimen collection for tonsillitis/pharyngitis
Throat swab
What is the specimen collection for the site of infection or a wound?
Swab or pus
What is the specimen collection for diarrhoea?
Faeces
What is the specimen collection for bacteraemia?
Blood culture
What is the specimen collection for meningitis?
CSF
What does unstained microscopy allow you to see?
Pus cells (urine, CSF)
Parasites (faeces)
What does a gram stain allow you to see in microscopy?
If Bacteria present - gram -positive/negative
Presence of fungi and yeast
What does a ZN stain or an auramine stain allow you to see?
Mycobacteria (includes causative agents of leprosy and tuberculosis)
What infecting agent is not visible in light microscope?
Viruses
What is the difference in the function between gram stain microscopy and culture?
Microscopy - rapid, insensitive, can’t identify particular species
Culture - slower, more sensitive, conditions are suitable for expected species
How is the species identified?
Observable characters - Morphological, physiological, biochemical
DNA tests
Typing - determines strain within species
What are the sterile sites within the body?
CSF
Blood
Heart
Liver
Kidney
Bladder
What are the non-sterile sites in the body?
Skin
Nasopharynx
Urethra
Gut
lung
How are viral infections diagnosed?
Electron microscopy
Cell or tissue culture
Antigen detection
Detection of cytopathic effect
(structural changes in host cells caused by viral invasion)
Real time/multiplex PCR
Serology, determine immunity
(investigation of blood serum with regard to the response to an introduced pathogen or introduced substance)
What are the three different types of parasites?
Protozoa - malaria
Helminths (worms)
Arthropods - lice
How can parasites be diagnosed?
Microscopy of different stages - parasites, cysts and ova
blood films for malaria
Culture rarely possible
Serology is useful
Give some examples of healthcare acquired infection
Methicillin resistant Staph Aureus - MRSA
Clostridium difficile
Noroviruses
ESBL’s - Organisms with extended spectrum beta lactamases (give resistance to beta lactam bacteria)
