Article 2: Major Groups of Disease-Causing Bacteria (Article) Flashcards Preview

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Flashcards in Article 2: Major Groups of Disease-Causing Bacteria (Article) Deck (35)
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1
Q

Aerobic Gram-Positive Rods (3 important genera)

A

Bacillus, Corynebacterium, and Listeria

2
Q

Two medically important genera that produce spores

A

Bacillus and Clostridium

3
Q

Bacillus anthracis (Morphology, Spore Production, Motility, Unique Properties)

A

Large: end-to-end chains, Yes, No, Poly-D-glutamic acid capsule; spores

4
Q

Bacillus cereus (Morphology, Spore Production, Motility, Unique Properties)

A

Large, Yes, Yes; 50% of strains, Spores

5
Q

Corynebacterium diphtheriae (Morphology, Spore Production, Motility, Unique Properties)

A

Small and narrow, No, No, Pleomorphic; Chinese Characters (divides via snapping fission)

6
Q

Listeria monocytogenes (Morphology, Spore Production, Motility, Unique Properties)

A

Small, No, Yes; tumbling motion, Grows at 3-4 degrees C; grows intracellulaly

7
Q

Anaerobic Spore-Forming Gram-Positive Rods

A

Clostridium (only genus)

  • Produce endospores to survive adverse conditions
    e. g. C. botulinum, C. tetani, C. perfringens, C. difficile
8
Q

Clostridium botulinum

A
  • Fastidious spore-forming gram-positive rod shaped organism
  • Production of a NEUROTOXIN results in disease (i.e. flaccid paralysis)
  • Commonly isolated in SOIL and WATER
9
Q

Clostridium tetani

A
  • Tennis rackt/drumstick appearance due to terminal ENDOSPORE
  • Difficult to grow in vitro due to extreme OXYGEN SENSITIVITY
  • Production of a NEUROTOXIN (tetanospasmin) causes spastic paralysis (i.e. lockjaw, arching of back, and respiratory muscle spasms)
  • Commonly found in SOIL
10
Q

Clostridium perfringens

A
  • Hemolytic and produces several toxins (alpha, beta, epsilon, and iota)
  • Grows rapidly in tissue and in culture
  • NOT motile (unlike other Clostridia)
  • Cellulitis, suppurative myositis, gas gangrene, food poisoning
11
Q

Clostridium difficile

A
  • Associated with prior antibiotic use and other chemotherapies
  • Extremely sensitive to oxygen
  • WATERY DIARRHEA
12
Q

Gram-Positive Cocci

A

Staphylococcus, Streptococcus, and Enterococcus

13
Q

Staphylocci

A

Catalase POSITIVE and grow in large clusters

  • Grow in media with up to 10% salt
  • Aerobic or anaerobic
  • Found on skin and mucous membranes
14
Q

Streptococci

A

Catalase NEGATIVE and grow in chains

15
Q

Enterococcus

A

Catalase NEGATIVE and is in the Lancefield D group

16
Q

Staphylococcus aureus (Hemolysis, Catalase, Coagulase/Mannitol fermentation, Novobiocin)

A

Beta or gamma, Positive, Positive/Positive, Sensitive

17
Q

Staphylococcus epidermidis (Hemolysis, Catalase, Coagulase/Mannitol fermentation, Novobiocin)

A

Gamma, Positive, Negative/Negative, Sensitive

18
Q

Staphylococcus saprophyticus (Hemolysis, Catalase, Coagulase/Mannitol fermentation, Novobiocin)

A

Gamma, Positive, Negative/Negative, Resistant

19
Q

S. aureus

A
  • Coagulase POSITIVE
  • Most pathogenic and causes several diseases (e.g. food poisoning, toxic shock syndrome, scalded skin syndrome, impetigo/bullous impetigo, folliculitis, furuncles or boils, carbuncles, bacteremia and endocarditis, pneumonia and empyema, osteomyelitis, and septic arthritis)
  • Produces a golden pigment
20
Q

S. epidermidis

A
  • Coagulase NEGATIVE
  • ubiquitous inhabitant of human skin
  • forms biofilm on implanted medical devices (catheters, prosthetic joints, and heart valves)
21
Q

S. saprophyticus

A
  • Coagulase NEGATIVE
  • novobiocin resistant
  • Second most common cause of UTI in sexually active young women (ages 13 to 40 y.o.) following E. coli
22
Q

Streptococcus pyogenes (Lancefield grouping, Hemolysis, Biochemical tests)

A

A (GAS), Beta, Sensitive to Bacitracin (A disc)

23
Q

Streptococcus agalactiae (Lancefield grouping, Hemolysis, Biochemical tests)

A

B (GBS), Beta usually; sometimes Gamma, CAMP test positive; hippurate hydrolysis

24
Q

Streptococcus pneumoniae (Lancefield grouping, Hemolysis, Biochemical tests)

A

Nongroupable, Alpha; Viridians group, Soluble in bile; Sensitive to Optochin (P disc)

25
Q

Streptococcus pyogenes

A

Uniquely sensitive to Bacitracin compared to other beta hemolytic streptocci
Wide variety of diseases:
-Pharyngitis “strep throat”, Scarlet fever, Impetigo, erysipelas, cellulitis, necrotizing fasciitis, Streptococcal Toxic Shock Syndrome, Bacteremia, Sepsis, Cross-reactive antigen or immune complex disease (e.g. Rheuamtic fever, Acute glomerulonephritis)

26
Q

Streptococcus agalactiae

A

Produces diffusible heat stable factor (CAMP factor)

Early onset disease, Late onset disease, Adult diseases (UTIs and compromised adults)

27
Q

Streptococcus pneumoniae

A

LANCET-SHAPED or bull-shaped diplococcus

28
Q

Enterococcus

A

Catalase NEGATIVE

29
Q

Enterococcus faecalis and faecium

A

Both found in the GI or GU tract commonly

-Cause UTI, bacteremia, endocarditis, intra-abdominal abscesses

30
Q

Gram-Negative Bacteria: Gram-Negative Cocci

A

Neisseria

  • Two important species (N. meningitidis and N. gonorrhoeae)
  • Kidney bean-shaped; look like a coffee bean when two are lined up with their flattened sides
31
Q

Neisseria gonorrhoeae (Shape, Oxidase reaction, Acid via oxidation of carbohydrate, Media Requirements)

A

Diplococcus, Positive, Glucose only, Chocolate and Thayer-Martin agar

32
Q

Neisseria meningitidis (Shape, Oxidase reaction, Acid via oxidation of carbohydrate, Media Requirements)

A

Diplococcus, Positive, Glucose and Maltose, Blood or chocolate agar

33
Q

Enteric Gram-Negative Rods

A

Enterobacteriaceae:

  • Eschericia (rod shaped)
  • Salmonella (rod shaped)
  • Shigella (rod shaped)
  • Yersinia (rod shaped)

Non-Enterobacteriaceae:

  • Vibrio (comma shaped rod)
  • Campylobacter (comma shaped rod or S-shaped rod or corkscrew)
  • Helicobacter (spiral shaped rod)
  • Bacteroides (rod shaped; ONLY OBLIGATE ANAEROBE)
34
Q

Non-Enteric Gram-Negative Rods

A

Klebsiella (found in GI tract)
Haemophilus and Legionella (respiratory pathogens)
Francisella (ticks, black flies, rabbit skinning)
Pasteurella (animal bites)
Brucella (unpasteurized/imported dairy products)
Yersinia pestis (flea bites)
Rickettsia (tick bites)

35
Q

What two Non-Enteric Gram-Negative Rods are opportunistic infections (require a defect in the patients’ immune functioning)?

A

Pseudomonas and Kelbsiella