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Micro/Immuno > Anaerobic bacteria > Flashcards

Anaerobic bacteria Flashcards

1
Q

C tetani are what? How can it be introduced?

A

environmental, gram positive, and spore-forming; Think soil contamination of wounds like splinters, IV drugs, septic surgery, thorns

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2
Q

C tetani releases what? What are the four types of disease?

A

Exotoxin tetanospasmin;

  1. neonatal
  2. cephalic
  3. local
  4. generalized
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3
Q

Neonatal tetanus involves

A

contamination of umbilical cord and lack of materal immunization

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4
Q

Cephalic and local tetanus

A

both have low mortality so long as they remain local

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5
Q

In generalized tetanus, what happens to the exotoxin? What can lead to >50% untreated mortality?

A

It ENTERS THE BLOODSTREAM;

respiratory failure

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6
Q

In C tetani, the two subunits are

A

B and A, with B delivering A to end of motor neuron and A moves retrograde to CNS

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7
Q

The A subunit acts as what?

A

a protease, cleaving synaptobrevin in inhibitory motor nerves of the CNS

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8
Q

On C tetani exam, what are some hallmark features? Test that can demonstrate C tetani?

A
  1. Local rigidity, difficulty swallowing
  2. Strong muscle spasms/paralysis
  3. Trismus (lockjaw)
  4. Grimace (risus sardonicus)
  5. Look for the STRONG ARCHING OF THE BACK!;
    Spatula test: they bite down
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9
Q

Lab tests for C tetani include:

A
  1. Microscopy with tennis racket appearance

2. Bloodwork can confirm vaccination and rule out STRYCHNINE POISONING

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10
Q

For C tetani treatment, this includes

A

tetanus antitoxin to neutralize the toxin;
could use antibiotics like metronidazole, but wound often clear on presentation;
maybe benzo!!

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11
Q

Prevention of C tetani includes

A

vaccination, with tetanus toxoid, while adults get boosters every 10 years; unvaccinated adults can get vaccine at any time

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12
Q

C botulinum is a; presents as; most common sources of C botulinum?

A

gram +, spore-forming, environmental bacteria; foodborne botulism;
alkaline vegetables like home-canned beans or if the spores survive inadequate sterilization of pre-prepped foods

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13
Q

C bot: Germinating cells infected by ____ phage release what?

A

lysogenic; botulinum toxins, with A and B being most common

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14
Q

For C botulinum, what happens to germinating bacteria and the bot exotoxin? How do bot and tetani differ once they arrive at a neuromuscular junction?

A

The germinating bacteria typically die;

bot tetani will stay in periphery and affect ACh release!!

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15
Q

A consequence of Bot pathogenesis is

A

flaccid paralysis and could affect respiratory system

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16
Q

Two less common presentations of Bot include

A

Infant botulism (kid is floppy and has uncooked honey) and wound botulism (wound contaminated in IV drug user)

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17
Q

On exam for bot, you would see in foodborne botulism

A

descending weakness and paralysis, and patient has history of suspect foods

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18
Q

For treatment of C botulinum what are you worried about? What is needed in wound botulism?

A

Horse-sourced antitoxin can inactivate toxin in bloodstream, which could lead to SERUM SICKNESS;
debride and high-dose IV penicillin

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19
Q

How to prevent C botulinum?

A

Cook adequately, sterilize the canned foods and vacuum-packed foods, and discard swollen cans!!

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20
Q

What can botulinum toxin A be useful for?

A

Cosmetics and blepharospasm (eyelid), writer’s cramp, anal fissures and torticollis

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21
Q

C perfigrens is a

A

gram pos spore-forming rod that can lead to necrotizing fasciitis/myonecrosis

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22
Q

How does C perfringens enter? What can be seen on histology?

A

Serious wounds like war, car accident, septic abortion, where you disrupt blood flow;
Gas production!!!

23
Q

C perfrigens can produce

A

alpha toxin with enzymes that break down tissue

24
Q

On exam, C perfringens can show

A
  1. Bronze skin color, then blue-black
  2. maybe develops at site of malignancy
  3. could see crepitation and tachy
  4. Then ARDS, renal failure, shock!!
25
Q

In C perfringens, what do you see on radiography, and what is needed to confirm myonecrosis?

A

Feathering pattern of gas in soft tissue;

SURGICAL EXPLORATION FIRST!!

26
Q

To treat C perfrigens and prevent it?

A

Can give antibiotics like penicillin G and clindamycin, or clindamycin with metronidazole;
clean and debride the wounds!!

27
Q

In C perfringens, besides gas gangrene, what can happen?

A

Food poisoning: inadqueate cooking fails to kill the bacteria and the spores grow up

28
Q

For C perfringens poisoning, what area is affected?

A

Type A enterotoxin can destroy tight junctions between epi cells in gut

29
Q

Tests, treatment and prevention for C perfringens food poisoning?

A

None required; DON’T STOP THE DIARRHEA;

Thorough cooking!!

30
Q

C difficile is a ____ that causes what? How can it emerge?

A

Gram positive, spore-forming rod; pseudomembranous colitis;

fecal-oral or can come up in normal gut flora and spike in hospitalized pop (maybe antibiotic use)

31
Q

What two toxins of C diff can cause issues?

A

Exotoxin A: disrupts tight junctions and causes intestinal swelling and inflammation
Exotoxin B: MAJOR TOXIN, disrupting cytoskeleton by depolymerizing acting, killing surrounding cells

32
Q

On C diff exam, what could be seen?

A

Nonbloody cramping diarrhea; antibiotic use, chemo, or immunsuppressants in history;
patches of dead cells on sigmoidoscopy, maybe toxic megaolon or colonic perforation

33
Q

Treatment of C diff?

A
  1. Withdraw initial antibiotics
  2. Unless disease is very mild, give oral metronidazole or vanco
  3. LET TOXINS FLUSH
  4. Maybe removal/surgical resection of colon
34
Q

Bacteroides and prevotella are

A

gram-negative bacilli that are NON-SPORE forming; these guys are opportunistic pathogens that are in normal flora of mucous membranes

35
Q

Treatment of B and P complicated by

A
  1. slow growth (potential antibiotic resistance)

2. polymicrobial, so if one secretes beta-lactamase, whole abscess/colony protected from penicillin!!

36
Q

Abscesses for B and P start off as ___ which use up the O2, followed by?

A

Facultative anaerobes; anaerobes

37
Q

Diagnosis of B and P includes in the history:

A

Painful abscess that could move to meningitis (neck)

38
Q

B and P are usually found

A

below the diaphragm if B, above if P

39
Q

B and P can be diagnozed lab-wise via

A

needle aspiration (bypass normal flora and maintain anaerobic condition); MAKE SURE YOU CULTURE ON ANAEROBIC BLOOD AGAR; identify by sugar fermentation and gas chromatograpohy

40
Q

Treatment and prevention of B and P includes

A

metronidazole primarily, and combine with aminoglycides to kills facultatives in abcesses, REQUIRES SURGICAL CARE;
perioperative cephalosporin

41
Q

Actinomyces are

A

gram+ filmaentous rods, non spore-forming; anaerobitc to microaerophilic and normal flora of mouth, vag

42
Q

Actinomyces pathology includes

A

bacteria escaping proper compartment during trauma; non-comm, with good prognosis

43
Q

Presentations of actinomyces include:

A
  1. Head/neck: pus drainage and hard, non-tender swelling in face, neck, chest; history of dental work, poor dental hygiene
  2. Abdomen: slow-growing tumor and usually diagnozed on EXPLORATORY SURGERY
44
Q

For actinomyces: you’ll see on lab; treatment could include

A

branching Gram+ rods with sulfur granules; can be anaerobically cultured;
penicillin G with possible surgical drainage

45
Q

SS: Anaerobic infections usually follow

A

deep-tissue trauma: accidents, cancer, surgery, immunosuppression, IV drug use

46
Q

SS: For what is there a vaccine available?

A

ONLY TETANUS

47
Q

SS: All of the anaerobes here are? What is gram pos and neg?

A

RODS;

Clostridia and actinomyces are gram pos, B and P are gram neg

48
Q

SS: of the bacteria in this lecture, which are environmental, normal flora, both?

A

Environmental: C tetani, botulinum;
normal: C difficile, B and P, and actinomyces;
Both: C perfringens

49
Q

SS: C tetani and botulinum produce

A

neurotoxins with same protease activity butopposite clinical effects because of nerves affected: tetanospasmin inhibitor CNS leads to spasms, botulinum toxin stimulatory on periphery, leading to flaccid paralysis

50
Q

SS: Diagnosis of C tetani and botulinum includes; infection is usually; how do you treat? who is affected?

A

exam; the infection is usually transiet; treatment is primarily with ANTITOXIN to bind and inactivate neurotoxin; you would see this in neonates, IV drug users, infected wounds, botulism in contaminated food

51
Q

SS: C perfringes in gas gangrene, B and P produce; how do you identify and treat? What’s special about gas gangrene?

A

tissue-degrading enzymes;
identify by anaerobic culture and gas chromatography, treat with antibiotics plus surgical care; resolved ASAP: lethal exotoxemia

52
Q

SS: C perfringens in food poisoning produces

A

enterotoxin: symptomatic treatment

53
Q

SS: C difficile causes ____ after what? How to treat?

A

pseudomembranous colitis; antibiotic use;

often nosocomial, change antibiotic and intervene SURGICALLY as necessary

54
Q

SS: Actinomyces produces ____ containing what? Where is it found and how do you treat?

A

nodules; pus with sulfur granules;

mouth or colon and treat with penicillin with surgical care as necessary

Micro/Immuno (34 decks)

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