TC4. genetics, antibiotic resistance, oral & stomach, UTI Flashcards
(31 cards)
transformation vs transfection
transfOrmation = for prOkaryotes. with plasmids
.
transfEction = for Eukaryotes. in lab. using viral DNA or + ssRNA
what’s special about treating a person with Enterohemorrhagic E.coli (EHEC)?
DONT GIVE THEM ANTIBIOTICS the damage they cause to the cell will trigger production of more shigalike toxin -> more severe case
the 5 examples of lysogenic conversion
- Salmonella- O antigen
- botulinum toxin
- strep pyogenes toxins for scarlet fever
- corynebacteria infected with cornephage B make diphtheria
- phage CTX(flux) makes V. cholerae make cholera toxin
gram negative, lactose positive, alpha hemolytic motile facultative anaerobic bacilli
E. coli
the 4 virulence factor in E. coli and what they do
- type 1 fimbriae - bind to mannose on glycoproteins that line the bladder.
- P fimbriae is specific to bad E. coli and is required for pyelonephritis. bind to galactose disaccharides on renal cells
- endotoxin
- a-hemolysin
to ID e.coli what do you look for in urine? what 2 agars?
urine - nitrite. bc e.coli turns nitrate -> nitrite
.
MacConkey agar - lactose positive. pink colonies
eosin-methylene blue (EMB) agar - green metallic sheen
gram positive
non hemolytic
coagulase negative
cocci in clusters
UTIs especialy in young newly sexually active females
Staph. saprophyticus
remember, the coagulase negative is important bc thats all the staph besides staph aureus. hemolytic activity varies among the staphs
resistant to novobiocin
staph saprophyticus
.
important for differentiating it between staph aureus and epidermidis
the ones that can cause complicated UTI/pyelonephritis
Proteus mirabilis Proteus vulgaris Klebsiella pneumoniae Serratia marcescens Pseudomnas aeruginosa enterococcus faecalis Strep agalectiae (group B strep) Candida albicans Polyomaviridae: BK virus
gram negative bacilli
lactose negative
can swim or even swarm/crawl
produces H2S (hydrogen sulfide) and urease
Proteus mirabilis and Proteus vulgaris
what does the virulance factor urease do and who has it
P. mirabilis and vulgaris have it
.
it cleaves urea to form ammonia -> increase pH (~8) -> protects bacteria from immune system and antibiotics, causes stones, and makes urine smell like ammonia
gram negative bacilli nonmotile lactose fermenting weakly urease positive hospital equipment easily contaminated
Klebsiella penumoniae
what about klebsiella pneumoniae helps it escape phagocytosis?
very large polysaccharide capsule (remember picture)
gram negative bacilli
salmon red pigment
likes damp places like showers and soap
Serratia marcescens
gram negative bacilli
in water and soil
biofilms.
grape smell
makes pyocyanin and pyoverdine -> green on plate
.
what is it and what virulence factor does it have?
Pseudomonas aeruginosa
has exotoxin A = ADP ribosylates EF-2. stops protein synthesis
gram positive cocci in chains
catalase negative
very hardy
grow in bile, turn bile esculin agar black
Enterococcus faecalis
gram positive diplococci in chains catalase negative Beta-hemolytic bile soluble bacitracin resistant can hydrolyze hippurate positive CAMP test with staph aureus . what is it. who does it affect. clinical implications
Strep agalactiae (group B strep) . infects pregnant women. need to screen women at 35-37 weeks gestation and give antibiotics if necessary so it doesn't affect baby and cause bacteremia, pneumonia, and meningitis
has both yeast and hyphae in infected tissues
true hyphae during invasion, pseudohyphae in infections
candida albicans
enters through respiratory tract -> latent infection in kidney, especially in immunosuppressed
.
what is it and what infections does it cause in each patient group
polyomaviridae: BK virus
.
infections:
1. tubulointerstitial nephritis and ureteric stenosis in kidney transplant patients,
2. hemorrhagic cystitis in bone marrow transplant patients
gram negative spirochete
use silver stain
reservoir is wild and domestic animals, transmitted by animal urine in water
.
what is it and what infection does it cause?
Leptospira interrogans
.
causes leptospirosis (weil’s dz) - flu like illness, conjunctival suffusion (crazy red looking eye)***,
if untreated can lead to hepatitis, renal failure, meningitis
gram positive cocci in chains beta hemolytic catalase negative bacitracin sensitive . what precedes infection of this organism and what is it
strep pyogenes (group A strep)
.
preceded by pharyngitis or impetigo (skin infection with golden crust). throat or skin, throat or skin.
.
it causes glomerulonephritis. post strep GN.
what are the most problematic antibiotic resistant organisms? ESKAPE
Enterococcus faecium (Vancomycin resistant) Staph aureus (MRSA) (SSmec) Klebsiella pneumoniae Acinetobacter Pseudomonas aeruginosa Enterobacter species
bonus: mycobacterium
what “thing” gives staph methicillin resistance, turning them from MSSA to MRSA
SCCmec. staphylococcal cassette chromosome. it’s a gene cassette. it makes alternative PBP2a transpeptidase that is not inhibited by antiobiotics
gram positive cocci catalse negative alpha hemolytic optochin resistant normal oral microbiota
viridans streptococci, S. mutans
btw strep pneumoniae is optochin SENSITIVE