Bacteria Flashcards
what does microbiology mean?
the study of microorganisms and their relationships with humans
what is a microorganism?
any organism/ replicating entity that is of a microscopic size or small
what are the categories of microorganisms
cellular (bacteria, fungi, protozoa)
acellular (viruses, prions)
what are prokaryotes
(bacteria) organisms without membrane bound organelles. transcription and translation is couples, they have a single circular DNA with additional DNA in plasmids
what are eukaryotes?
DNA carried on chromosomes in a membrane bound nucleus. cytoplasm is rich in membrane bound organelles
what are bacteria?
single celled prokaryotes. DNA in long circular form. thick cell wall and a thick capsule.
how do bacteria reproduce?
binary fusion
what determines gram positive or negativity
peptidoglycan
why would bacteria be gram stain unreliable?
to small a cell wall
if there is a large amount of peptidoglycan the cell will be?
gram positive
if there is a small amount of peptidoglycan the cell will be?
gram negative
where in the body is sterile?
blood, tissues, organ systems, CNS, lower respiratory tract, sinuses, inner and middle ear, renal system down to posterior urethra, female reproductive track down to the cervix and the eye
what Is the definition of a parasite?
an organism that lives in or on another organism and benefits on deriving nutrients at the others expense.
what is the definition of an opportunistic infection
an infection usually via a less frailest organism that might cause harm to an immunocompromised person
what is a nonsocomical infection
hospital acquired infection
what is a carrier state?
the condition of harbouring an infective organism without manifesting symptoms of infection
what is an endotoxin?
the outer membrane of a gram negative bacteria which elicits strong immune responses and can make patients appear septic
what are exotoxins (super antigens)?
they are liberated by certain gram positive bacteria. produced intracellularly and released as mature toxins on infection. they have massive immune stimulation. (toxic shock syndrome)
what is the meaning of sepsis?
a psychological response to severe infection involving cytokine cascades, free radical production and vasoactive mediators
what is meant by the chain of infection/
infectious agent, reservoirs, portal of exit, means of transmission, portal of entry, susceptible host
what are examples of specimen processing?
microscopy, culture, PCR
What are some cellular microorganisms?
-bacteria
-fungi
-protozoa
What are some examples of acellular microorganisms?
Viruses
Prions
What is pilli function?
An attachment, either to bacteria or to host cells. Presence of multiple pilli is a factor in resistance to phagocytosis.
What is the structure of DNA in bacteria?
Long circular form, + or -
What does positive sense DNA?
The nucleotide sequence corresponds directly to the sequence of an RNA transcript.
What dyes are used when bacteria is gram stained?
Flood with crystal violet and iodine
Iodine helps crystals form complexes with peptidoglycan
Example of gram positive cocci?
Streptococcus
Staphylococcus
Example of gram - cocci?
Neisseria
Moraxella
Example of gram + bacilli?
Bacillus
Acranobacterium
Example of gram negative bacilli?
Bacteroides
what colour do gram positive Bactria come out?
purple
what colour do gram negative bacteria come out?
pink
what are some benefits to normal flora?
-byproducts released means pathogens find it harder to establish True infection
-produce vitamins K and B in gut as metabolic end products
-keep immune system stimulated
where are the main sites of colonisation for normal flora?
-skin
-distal urethra
-colon
-distal GI tract
-upper resp tract
what are the sterile body sites?
-blood tissues and organ sites
-CNS
-lower resp tract
-sinuses, inner and middle ear
-renal system down to posterior urethra
-female reproductive tract down to cervix
-are behind conjunctiva in the eye
what does transient mean?
short-lived/passing
what forms the outer membrane of gram negative bacteria and elicit strong immune responses making patients appear septic?
AKA as lipopolysaccharide (endotoxic lipid A and O antigen
what is a biofilm?
ECM which the organism embeds into and antibiotics aren’t good at penetrating it
