MICROBIOLOGY-NON BRANCHING, CATALASE POSITIVE, GRAM-POSITIVE BACILLI (BACILLUS AND SIMILAR ORGANISMS) Flashcards

1
Q

o Aerobic
o Facultative or strictly anaerobic
o Gram-positive
o Spore-forming rods

A

Bacillus

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2
Q

What are the characteristics of Bacillus anthracis?

A
  • Aerobic
  • Gram-positive box
    car-like rods
  • Nonmotile
  • Spore-forming
    (endospores)
  • Nonhemolytic ”comet
    tail or Medusa head”
    or ground glass
    colonies on 5% sheep
    blood agar
  • Rarely found
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3
Q

HABITAT ni Bacillus anthracis

A

In soil, contracted by various herbivores

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4
Q

MODE OF TRANSMISSION ni Bacillus anthracis

A
  • Direct contact: animal tissue or
    products such as wool or hair
  • Traumatic or insect bites: organisms
    or spores
  • Injection: contaminated drugs
  • Ingestion: contaminated meat
  • Inhalation: spores; during exposure
    to animal products (wool sorter’s
    disease)
  • Person-to-person transmission (rare)
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5
Q

Virulence Factor ni Bacillus Anthracis

A

Lethal toxin and Edema Toxin

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6
Q

It is primarily responsible for death.

A

lethal toxin (LT)

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7
Q

It facilitates the transport of other proteins into the cell.

A

protective antigen (PA)

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8
Q

It is responsible for edema.

A

edema toxin (ET)

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9
Q

Name the functional enzymes involved in virulence factors.

A

Lethal factor (LF) and Edema factor (EF).

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10
Q

What type of anthrax accounts for most human infections?

A

Cutaneous anthrax.

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11
Q

How is cutaneous anthrax contracted?

A

Through contact with infected animal products and inoculation of endospores through a break in the skin.

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12
Q

What are the symptoms of cutaneous anthrax?

A

Papule ring of vesicles leading to ulceration (eschar).

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13
Q

How is cutaneous anthrax treated?

A

it is effectively treated with antibiotics.

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14
Q

How is gastrointestinal anthrax contracted?

A

By ingestion of endospores.

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15
Q

What are the two forms of gastrointestinal anthrax?

A

Oral or oropharyngeal (buccal cavity or tongue, tonsils, or pharyngeal mucosa) and gastrointestinal (mucosa of the terminal ileum).

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16
Q

What was inhalation anthrax previously referred to as?

A

Pulmonary anthrax.

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17
Q

How is inhalation anthrax contracted?

A

By inhalation of endospores.

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18
Q

What are the initial symptoms of inhalation anthrax?

A

Flu-like symptoms: fever, chills, fatigue, nonproductive cough, nausea, and vomiting.

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19
Q

What are the advanced symptoms of inhalation anthrax?

A

Respiratory distress, edema, cyanosis, shock, and death.

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20
Q

What are the common name for inhalation anthrax?

A

Woolsorters’ disease and ragpickers’ disease.

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21
Q

What are the chest X-ray findings in inhalation anthrax?

A

Pleural effusion, infiltrates, and mediastinal widening.

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22
Q

How is injectional anthrax contracted?

A

Through contaminated drugs of abuse (heroin).

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23
Q

What are the symptoms of injectional anthrax?

A

Severe soft tissue infection and dissemination leading to septic shock.

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23
Q

How should specimens be collected for laboratory diagnosis of anthrax?

A

Specimens should be collected in leak-proof containers and placed in a secondary container.

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24
Q

Where should samples be taken from for cutaneous anthrax diagnosis?

A

Samples should be taken from underneath the eschar.

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24
Q

What type of testing is used for cutaneous anthrax?

A

Histochemical testing with a punch biopsy in 10% formalin.

25
Q

What specimens are collected for inhalation anthrax diagnosis?

A

Blood cultures, pleural fluid, and serum for serology.

26
Q

What tissues are biopsied for inhalation anthrax?

A

Bronchial tissue or pleural tissue.

27
Q

What specimens are collected for gastrointestinal anthrax diagnosis?

A

Blood cultures, ascites fluid, material from any lesions, and serum for serology.

28
Q

What are the direct detection methods for anthrax?

A

Detection of large, gram-positive rods in singles, pairs, or serpentine chains.

29
Q

What is the width of vegetative cells of B. anthracis?

A

The vegetative cell width is usually greater than 1µm, and the endospores do not cause swelling of the cell.

30
Q

It is used for the selection and isolation of B. anthracis from contaminated species.

A

Polymyxin-lysozyme-EDTA-thallous acetate (PLET)

30
Q

What media are used for the cultivation of B. anthracis?

A

5% sheep blood agar, chocolate agar, routine blood culture media, and nutrient broths.

31
Q

Medium-large, gray, flat irregular with swirling projections (Medusa head or comet tail) or ground glass appearance, nonhemolytic.

A

B. anthracis

32
Q

it induces B. anthracis capsule formation, resulting in large and mucoid colonies.

A

bicarbonate agar

33
Q

purpose of heat shock treatment in the cultivation of B. anthracis?

A

-is used for the growth and enhancement of endospores from clinical specimens

-typically at 62-65°C for 15-20 minutes.

34
Q

What serodiagnostic methods are used to detect antibodies to B. anthracis?

A

Indirect hemagglutination and ELISA.

34
Q

What antigens or proteins are typically detected in serodiagnosis of B. anthracis?

A

PA antigen, toxin protein, LF, and EF.

35
Q

What is the treatment for severe anthrax?

A

IV ciprofloxacin (7-10 days) plus one aminoglycoside or two additional drugs.

36
Q

What genetic analysis methods are used for B. anthracis?

A

Multilocus sequence typing (MLST) and multiple-locus variable-number tandem-repeat analysis.

37
Q

What is the treatment for cutaneous or uncomplicated anthrax?

A

Oral ciprofloxacin or doxycycline for 7-10 days.

38
Q

What are the prevention methods for anthrax?

A

-Cell-free inactivated vaccine
-chemoprophylaxis with ciprofloxacin or doxycycline after aerosol exposure to B. anthracis.

39
Q

IDENTIFY

is crystal-forming and cold-tolerant.

A

Bacillus thuringiensis

40
Q

is known for being heat-tolerant?

A

Bacillus weihenstephanensis

41
Q

is known for being a probiotic.

A

Bacillus cytotoxicus

42
Q

Name three other species in the Bacillus cereus group

A

Bacillus toyonensis,Bacillus mycoides and B. pseudomycoides

43
Q

HABITAT sa Bacillus cereus group

A
  • Soil
  • Widely distributed in
    nature
  • Vegetative cells and
    spores ubiquitous in
    nature; may
    transiently colonize
    skin or GIT or
    respiratory tracts
44
Q

MODE OF TRANSMISSION sa
(Bacillus cereus group)

A
  • Trauma
  • Associated with immunocompromised patients
  • Predominantly ingestion
    of food (rice) contaminated with B. cereus-type species or toxins formed by this organism
45
Q

IDENTIFY THE TOXINS

Diarrheal symptoms.

A

Hemolysin BL (HBL)

46
Q

How do Hemolysin BL (HBL) and Nonhemolytic enterotoxin (Nhe) act?

A

They act synergistically.

47
Q

Which toxin is responsible for the major symptoms in diarrheal presentation?

A

Nonhemolytic enterotoxin (Nhe).

48
Q

What is another name for Cytotoxin K?

A

Hemolysin IV.

49
Q

Which toxin is a heat-stable, proteolysis, and acid-resistant toxin.

A

Cereulide

50
Q

What form does Cereulide cause?

A

Emetic form.

51
Q

What systemic conditions can Bacillus species cause

A

Bacteremia, endocarditis, and septicemia.

52
Q

What are some health-care associated infections caused by Bacillus species?

A

Contaminated gowns, gloves, linens, dressings, and medical devices (ventilators, catheters, and bronchoscopy equipment).

53
Q

What toxin does B. thuringiensis harbor?

A

Cereulide toxin.

54
Q

What are the two types of symptoms of food poisoning caused by Bacillus species?

A

Diarrhea and abdominal pain within 8-16 hours, and nausea and vomiting (emetic food poisoning) within 1-5 hours.

55
Q

What is the commercial use of B. thuringiensis toxins?

A

They are used for the control of insects that cause agricultural damage (moths, beetles, flies, and parasitic worms).

56
Q

Large gram-positive rods in singles, pairs, or serpentine chains, and endospores that may appear as gram variable.

A

Bacillus cereus group

57
Q

What media are used for the cultivation of Bacillus species?

A

-5% sheep blood agar,
-chocolate agar,
-routine blood culture media,
-nutrient broths,
- specific Bacillus cereus media like MEYP, PEMBA, and BCM.

58
Q

What is the purpose of heat shock treatment in Bacillus species?

A

To kill vegetative cells and retain spores, effective at 70°C for 30 minutes or 80°C for 10 minutes.

59
Q

What serodiagnostic methods are used for detecting B. cereus toxin in food and feces?

A

Oxoid BCET-RPLA and TECRA VIA.