Bacteriology

Question 1

are bacteria prokaryotes or eukaryotes

Answer 1

prokaryotes

Question 2

prokaryotes

Answer 2

• lack membrane bound organelles
• smaller/less complex
• one circular chromosome
• +/- plasmids

Question 3

plasmids

Answer 3

extra-chromosomal DNA

can carry antibiotic resistance or extra genes that make bacteria more virulent

Question 4

how are bacteria most commonly classified

Answer 4

genus +/- species

Question 5

bacteria morphology

Answer 5

shape of bacteria
- coccus: round/spherical
- bacillus: rod shaped
- coccobacillus: shortened rod shaped
- spirillum/spirochete: spiral

Question 6

gram-positive

Answer 6

thick peptidoglycan layer
- stains dark purple

NO outer cell membrane

Question 7

gram positive cocci

Answer 7

staphylococcus
streptococcus
enterococcus

Question 8

gram positive rods

Answer 8

bacillus
listeria
erysipelothrix
corynebacterium

Question 9

gram-negative

Answer 9

thin peptidoglycan layer
- stains red/pink on gram stain

HAS outer cell membrane

Question 10

gram negative rods

Answer 10

E. coli
klebsiella
pseudomonas

includes enterobacterales and non-enterobacterales

Question 11

enterobacterales vs non-enterobacterals

Answer 11

enterobacterales: facultative anaerobes that are present in GI tract

non-enterobacterales: facultative anaerobes or strict anaerobes

Question 12

gram negative spirals

Answer 12

leptospira
borrelia

Question 13

are gram negative cocci common in vet med

Answer 13

no - rare

Question 14

mycoplasma

Answer 14

bacteria with no cell wall

Question 15

aerobes

Answer 15

bacteria that can grow in the presence of oxygen

includes strict aerobes and facultative anaerobes

Question 16

strict aerobes

Answer 16

only grow in the presence of oxygen

Question 17

facultative anaerobes

Answer 17

bacteria that can grow with or without oxygen

Question 18

microaerophilic aerobes

Answer 18

requires reduced oxygen

Question 19

obligate anaerobes

Answer 19

bacteria that can only grow in the absence of oxygen

• clostridium, bactericides, fusobacterium

Question 20

where are obligate anaerobes found

Answer 20

top of the epithelium of:
- oral cavity
- intestinal lumen
- mucus membranes of urogenital tract

common in abscesses due to being walled off from the body

Question 21

what are bacterial toxins

Answer 21

endotoxins and exotoxins

Question 22

exotoxin characteristics

Answer 22

• gram positive and negative
• released by live bacteria
• proteins or polypeptides
• NOT pyrogenic
• highly antigenic
• converted to toxoids that induce neutralizing antibodies
• potent toxins
• some variation between bacterial species and species affected

Question 23

endotoxin characteristics

Answer 23

• gram negative
• released by dead bacteria
• lipopolysaccharides
• pyrogenic
• weakly antigenic
• not converted to toxoids, no neutralizing antibodies
• moderate toxins
• significant variation between bacterial species and species affected

Question 24

lipopolysaccharide (LPS)

Answer 24

endotoxin found in gram negative bacterial outer membrane

causes inflammation

made of lipid A, core polysaccharide, O side chain

Question 25

exotoxins

Answer 25

protein secreted from bacterial cells that cause host cell damage or disruption of function often antigenic - antitoxin = antibody to exotoxin

Question 26

A-B exotoxins

Answer 26

disrupt cell function

Question 27

disorganizers exotoxins

Answer 27

disrupt the host cell membrane (phospholipase, hemolysins, pore-forming)

Question 28

superantigens

Answer 28

cause a massive stimulation of T cells

Question 29

flagella

Answer 29

responsible for motility

Question 30

pili and fimbriae

Answer 30

polypeptides used for adhesion to host cells and sexual conjugation of genetic material

Question 31

capsule

Answer 31

polysaccharide or polypeptide surrounding bacterial cells used by both gram positive and negative inhibits complement fixation and phagocytosis

Question 32

spores

Answer 32

dormant/inactive bacterial state in which the bacteria forms an extremely resistant bacterial wall resistant to temperature, drying, chemical agents, host degradation mostly gram POSITIVE

Question 33

genetic transfer

Answer 33

acquisition of new genes allows for development of resistance and virulence - conjugation - transduction - transformation - transposition

Question 34

conjugation

Answer 34

transfer of plasmids by sexual pili

Question 35

transduction

Answer 35

genetic material transferred by bacteriophages

Question 36

transformation

Answer 36

take up of naked DNA

Question 37

transposition

Answer 37

transfer of mobile DNA

Question 38

biofilms

Answer 38

multilayered bacterial community; bacteria are IMMOBILE/INACTIVE become embedded in polysaccharide matrix - matrix blocks entry of antimicrobials/immune system components allows for adherence to surfaces