MLTD 1103

Clinical micro

what is "clinical"?

in relation to the treatment of patients

what is "microbiology"?

the study of microorganisms

what is clinical microbiology?

the study of microorganisms that cause or are associated with human disease

what are the 4 types of microorganisms ?

bacteria, fungi, parasites, viruses

what are bacteria?

single celled, prokaryotes

why dont we cover cyanobacteria?

they arent really associated with human disease

what are fungi?

single or multicellular, eukaryotes

what are yeast and mold?

types of fungi

what is a type of yeast we will study?

candida

What are dimorphic fungi?

grows as yeast at human body temperature, and mold at room temperature

why dont we deal with dimorphic fungi?

dimorphic fungi is risk group three, we are a level 2 leb.

what are parasites?

organisms that live at the expense of their host.

what are the three groups of parasites?

protozoa, helminths, and ectoparasites

what is an example of protozoa?

Giardia lamblia

what is an example of helminths?

enterobius

what is an example of an ectoparasite?

lice

what are ectoparasites?

parasites that live outside a host

what are viruses?

non-cellular infectious particles

why dont we look at viruses under a microscope?

they are too small

how do viruses reproduce?

by infecting a host cell

how can labs observe viruses?

by growing cells and infecting them

what is a prion?

misfolded proteins that cause other nearby proteins to misfold

what is prion short for?

proteinaceous infectious particle

what can/do prions cause?

neurological problems.

what is "c and s" testing?

culture and sensitivity testing

what other infectious materials are considered pathogenic by PHAC?

toxins, biotechnology, and cell lines

what does "culture" in c and s testing mean?

patient samples are received and grown on media for identification.

what are flora?

harmless bacteria typically found in your body

what are pathogens?

harmful microorganisms found in your body

what is "sensitivity" in c and s testing?

testing what drugs/treatments work on a specific pathogen

why is a negative sensitivity result important?

negative results help to rule out some pathogens, as well as can help point towards viral infections opposed to bacterial.

what information do we want to know about a sample?

the name of the identified sample, where its commonly found, its atmospheric and temperature preferences, what it eats, and what it does.

what can we use to describe the appearance of a bacteria/sample

colour, transparency, texture, gram pos/neg, etc.

what types of things happen during day 1 in a microbiology lab?

samples are received, media is inoculated with the sample, direct gram stain.

what is the main purpose of work done on day 1 in a micro lab?

preparation for further testing

what happens in days 2-4 of a micro lab?

inoculated plates are incubated and grown, sub cultures are made to isolate the pathogen, susceptibility testing.

what types of samples will we be sent in a micro lab?

blood, tissue, bodily waste, medical hardware, etc.

what are the 3 tests reported to physicians?

direct gram stain, species names, and susceptibility

what is taxonomy?

the system to classify, name, and identify all organisms.

what is phylogeny?

the evolutionary history of organisms

what are the 3 main components of microbial taxonomy?

classification, nomenclature, and identification.

polyphasic taxonomy

combination of genotype and phenotype to identify organisms

what is phenotypic?

expressed characteristics

what is genotypic?

the genetic make up (DNA/RNA) of an organism

what is chemotaxonomy?

the chemical composition of an organism

what are epigenetics?

the changes in gene expression, such as a specific gene not being expressed

which part of a scientific name is most likely to change?

the genus

what is the pyramid of taxonomic classes from most broad to least

domain, kingdom, class, phylum, order, family, genus, species

what are the 3 domains?

Bacteria, Archaea, Eukarya

what are prokaryotes?

non-membrane bound nucleus

what are eukaryotes?

organisms with a membrane bound nucleus

what is a strain?

a genetic varient/ subtype within a species

when typed how should the genus and species name be formatted?

italicized, second name not capitalized

when hand written how should genus and species name be formatted?

underlined, second name not capitalized

what should NEVER be on lab reports?

abbreviations

if you arent specifying/dont know the species how would you write it?

"genus" sp. or spp.

additional infromation like immunity or shape would be included where?

before the genus

when writing a new genus name next to an old one how would you do it?

"new genus" (old genus) "species"

what phenotypic characteristics are used to classify microorganisms?

macroscopic appearance, microscopic appearance, staining characteristics, environmental requirements, nutritional requirements, resistance profiles, antigens, sub culture properties, and chemotaxonomy.

what are the genotypic characteristics used to classify m/o?

DNA/RNA sequencing, 16s DNA, and PCR

what are the different factors we look at for colony morphology?

size, shape, smell, hemolysis, texture, and colour.

what are the factors we look at for microscopic morphology?

stain reaction, shape, size, and cell arrangement

what are antigens?

molecules found on the surface or interior of a bacteria that produce an immune response

what happens when an antigen is in the presence of her antibodies?

they clump or "agglutinate"

what does MALDI-TOF stand for?

matrix, assisted, laser, desorption, ionization, time, of, flight

what is 16s DNA

a specific gene found only in prokaryotes

what is the cell envelope?

all the structures making up the external wall of a bacterial cell.

what components make up the cell envelope?

outer membrane

cell wall

cell/cytoplasmic membrane

periplasm

capsule

order the components of the cell wall from exterior to interior

capsule

outer membrane

cell wall

periplasm

cytoplasm/cell membrane

what cell envelope features are found in all bacteria?

cell wall

cytoplasmic membrane

what features do only gram-neg bacteria have in their cell envelope?

outer membrane

periplasm

what cell envelope feature is only found in some bacteria?

capsule

what is the Lipid Bilayer made up of?

lipopolysaccharides

what are lipopolysaccharides also known as?

endotoxin or O-antigen

what does the outer membrane mean for the surface of gram-neg bacteria?

it gives the surface a negative charge

what does the outer membrane do?

acts as a barrier to the surrounding environment and regulates the passage of nutrients and other molecules.

what are the proteins in the outer membrane that regulate molecule passage called?

porins

what can proteins on/in the outer membrane aid in?

adhesion to host cells

what is the cell wall composed of?

peptidoglycan

what is peptidoglycan also called?

murein

what is the structure/rigidity of the cell wall?

strong ridged structure

why do bacteria need a ridged cell wall?

they have a high internal osmotic pressure and will lyse without it

why is the cell wall a good target for antibiotics?

human cells do not have cell walls

what are some features of a gram-positive bacteria's cell wall?

thicker, contains tiechoic acid and sometimes lipoteichoic acid

what does Teichoic acid do?

provides flexibility to the cell wall

what does lipoteichoic acid do?

a variation that attaches to the cell wall to the inner membrane.

what is a feature of gram-negative bacteria's cell wall?

thinner, sandwiched in between the inner and outer membranes of the cell, this space is called the periplasmic space.

what cell structure contains mycolic acid?

acid-fast cell wall

what does mycolic acid form on the outside of the cell wall?

a waxy layer

what does the waxy layer formed by mycolic acid do?

makes the cell less permeable to water and water soluble dyes

what are bacteria containing mycolic acid called?

acid-fast bacilli (AFB)

what type of stain is used to dye AFB?

specific stains as it resists being decolorized with acid decolorizers

what are the most common genera to have mycolic acid?

Mycobacterium and Nocardia

what are 2 genera of bacteria that have no cell wall?

mycoplasma and ureaplasma

what does pleomorphic mean?

lack of rigidity with no specific shape

why do bacteria with no cell walls not show up on stains?

there is no cell wall to trap the dyes

what type of bacteria has a periplasmic space?

gram-negative bacteria

where is the periplasmic space located?

between the outer membrane and cell membrane

what does the periplasmic space do?

contains and concentrates enzymes that may help break down or detoxify some molecules

what important molecule is included in the ones detoxified in the periplasmic space?

antibiotics!