Microbes 1 and 2 Flashcards

1
Q

Lipopolysaccharide is found on the outer membrane of the cell wall in a gram ___ bacteria, which causes:

A

gram negative bacteria, causes a strong inflammatory response. IL-1, TNF, NO induction, causes fever and hypotension.

Complement causes neutrophil recruitment, hypotension.

TF –> coagulation cascade.

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2
Q

if stains red, it is gram ____ and has ____.

if stains purple, it is gram ____ and has ____ acids

A
red= negative = Lipopolysaccharide
purple = positive = peptidoglycan and lipoteichoic acid
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3
Q

gram positive cocci in a clump or cluster

A

staphyloCOCCUS aureus

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4
Q

gram positive cocci in pairs and chains

A

streptoCOCCUS– S. pneumonia, s..pyogenes, enterococcus

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5
Q

gram positive bacilli that forms SPORES

A

clostridium, bacillus

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6
Q

gram positive bacilli that DO NOT form spores

A

listeria

corynebacterium

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7
Q

T/F CDif produces spores

A

true. it is a gram positive bacilli.

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8
Q

Gram negative cocci/diplococci

A

neisseria (N. gonorrhoea, N. meningitides)

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9
Q

Gram negative bacilli

A

E. coli/eterobacteriales. salmonella, shigella, yersinia.

pseudomonas aeruginosa
bacteria fragilis (normal gut flora)
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10
Q

CURVED gram NEGATIVE bacilli

A

campylobacter
h. pylori
vibriocholeae

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11
Q

species that poorly gram stain

A

mycobacterium

spirochetes (syphilis, Lyme disease)

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12
Q

All Bacilli are Gram negative except the gram positive ones (ABCDLMNOP)

A
Actinomyces
Bacillus
Clostridium (spores, gram positive)
Diptheria/Corynebacterium
Listeria (no spores, but gram positive)
Mycobacterium (no stain)
Nocardia
Oh no, what's the last one
Propionibacterium
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13
Q

All cocci are gram positive except the gram negative ones NMV

A

Neisseria
Moaxellla
Veillonella

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14
Q

is clostridium anaerobic

A

yes

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15
Q

primary pathogen

A

one that regular causes disease even in an INTACT immune defence system.

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16
Q

commensal pathogen

A

organisms that are part of the normal human flora or environment that do not usually cause infection

17
Q

opportunistic pathogen

A

organisms that have the ability to cause an infection when the immune defences are impaired.

18
Q

superantigen

A

Non-specific stimulation of T cells  uncontrolled cytokine release (IL- 1, TNF)
i.e. Toxic Shock Syndromes of Group A Streptococcus, S.aureus

type of exotoxin

19
Q

ways of overtly overcoming our immune system

A

-overwhelmign it through toxin and enzymes, T cell infection

20
Q

ways of covertly overcoming our immune system

A
  • immune modulation
  • capsules: some pathogens have such a large capsule its hard to eat them. Disables phagocytosis.
  • biofilm production
  • antigenic variation: modifying their antigens so immune system cannot recognize them. or like mimicry (ex/ schistosome H. Adult worm in the host venous system coats itself wit host antigens to evade the immune response)
21
Q

what type of bacteria takes the longest to culture

A

mycobacteria. (10d-7weeks).

most gram positive and negative bacteria takes 18-48 hours to culture

22
Q

what is susceptibility testing

A

determines whether a pathogen is susceptible or resistant to a panel of antibiotics

23
Q

minimum inhibitory concentration

A

minimum concentration of an antibiotic required to inhibit microbial growth

MIC ≤ 0.06 ug/ml are sensitive MIC = 0.12-0.5 ug/ml is intermediate MIC ≥ 1 ug/ml are resistant

24
Q

differences between IgM, IgG.

What is window period and seroconversion?

A

IgM: usually indicates an acute infection
IgG: indicates a past infection or immunity.

Window Period: patient is infected, but antibody levels not developed to levels detectable.
Seroconversion: patient’s serology changes from negative to positive.

25
Q

virulence factors of streptococcus pyogenes (strep throat)

A
  1. capsulated; prevents phagocytosis
  2. toxins an enzymes aid evasion of immune system and can move through tissues
  3. pili M protein type antigen: prevents phagocytosis and ocmplement activation
  4. lipoteichoic acid (promotes adhesion to pharynx mucosa)
26
Q

cause of acute rheumatic fever (seen in strep infection)

A

it’s an autoimmune response- cross reaction of antibodies against organisms direced against self proteins. associated complication of M-type strains tha cause pharyngitis (like strep)

27
Q

hypersenstivity reactions (types 1-4)

A
  1. immediate hypersensitivity: mast cell IgE response, usually anaphylaxis
  2. cytotic: Ab binds to cell surface Ag mediating cytotoxicity. Cell necrosis
  3. Immune complexes: post-streptococcal glomerulonephritis. immune complexes form with host antibodies and GAS antigens. these complexes deposit in the kidney aand generate inflammation.
  4. delayed type. t cell mediated. Granuloma formation.
28
Q

is enterobacteriaceae gram positive or negative

A

gram negative.

29
Q

outline the enterobacteriaceae classes

A

YES, PECKSS

yersinia, EHEC/Ecoli, Salmonella, Proteus, enterobacter, citrobacter, klebsiella, shigella, serratia.

30
Q

which type of Ecoli is seen in small bowerl? Which one produced shiga toxin?

A

ETEC: Small Bowerl.
EHEC: large bowel, shiga-toxin producing.

31
Q

what is the major virulence factor that EHEC uses to cause disease? (Ecoli 0157:H7)

A

produces exotoxin (shiga toxin) Shiga toxin causes bloody diarrhea because it dirsupts protein syntehsis of mucosa. can also damage the endothelial cells causing HUS.

32
Q

treating EColi (EHEC)

A

it’s gram negative

  • carbapenems
  • FQ/ ciprofloxacin (broad)
  • aztreonams
  • aminoglycosides like tobramycin, gentamycin
  • monobactams
  • 4th gen cephalosporins like (ceftrixaone)
  • SEPTRA (TMP-SXT)

BUT: FIRST LINE IS TO NOT DO ANYTHING. just give oral rehydration and IV fluids.