Clostridia, Gram-Negative Anaerobes, Anaerobic Cocci

Front 1

Are anaerobic bacteria part of the normal flora of the body?

Back 1

Yes.

Front 2

Anaerobes predominated in the _____ of the colon.

Back 2

stool

Front 3

Anaerobes are a major part of the normal flora in these parts of the body?

Back 3

Mouth, throat, upper GI
Vaginal (genital) tract
Skin (sebaceous gland)

Front 4

Types of Anaerobes?

Back 4

Obligate (strict) anaerobes; Aerotolerant anaerobe

Front 5

Opportunistic anaerobic infections are common under these conditions?

Back 5

Trauma
Malignancy
Inflammation
Impaired blood supply
Surgery
Foreign body

Front 6

Acceptable Specimens for anaerobic cultures?

Back 6

Abscess fluid aspirates.
Surgically removed tissue.
Blood cultures.
Sputum
Bypass normal oral flora when collecting

Front 7

Unacceptable specimens for Anaerobic isolation attempts?

Back 7

Cough sputum & Superficially collected specimens from skin and wounds. (Avoid swabs where normal anaerobic flora are present and can contaminate.)

Front 8

Anaerobic specimen transport devices?

Back 8

Gassed out tubes; Anerobic gel for swabs

Front 9

Acceptable Transport Times for Survival of Anaerobes?

Back 9

No special anaerobic transport devices: Only a 30 - 120 minute survival time in pus.
If anaerobic transport device is used: 8-48 hours of survival.

Front 10

What is special about the media for anaerobic cultures?

Back 10

Extra rich agar base + 0.1% glucose:
Enrichments:
Vitamin K + hemin are essential
Yeast extract
Reducing agents: Cysteine

Need to also incubate for a minimum of 48 hours because some anaerobes grow more slowly.

Front 11

Clostridium perfringens general characteristics?

Back 11

Gram positive spore forming rod.

Front 12

Where is C. perfringens found?

Back 12

Colon and soil.

Front 13

C. perfringens culture characteristics?

Back 13

Double zone of hemolysis on blood agar (1)
Litmus milk stormy fermentation (2)
Easy to identify biochemically

Front 14

C. perfringens toxins?

Back 14

Alpha toxin: Main pathogenic factor
-Diffuses out killing all cells producing more necrotic growth areas for organism
Theta toxin
-Toxic for heart muscle & capillaries.
-Similar to Streptolysin O Enterotoxin
-Causes food poisoning.

Front 15

Where does gas gangrene caused by C. perfringens occur?

Back 15

Severe traumatic wounds (e.g. a gun shot) when the wound is contaminated with dirt and/or feces.

Front 16

Gas gangrene treatment?

Back 16

surgical debridement, place drain in wound, penicillin

Front 17

Clostridial endometriosis is caused by?

Back 17

C. perfringens infection of products of conception retained in uterus.

Front 18

C. perfringens food poisoning (an anaerobic counterpart to Bacillus cereus) is caused by? Symptoms?

Back 18

Symptoms due to enterotoxin:
Appear 8-24 (>10 hours usually) hours after eating food.
Organism in meat dishes kept on food warming trays. Multiplication occurs.
Nausea, abdominal pain, diarrhea.
Usually no vomiting.
Recovery within 24 hours.

Front 19

Clostridium tetani is found in?

Back 19

Spores are in animal manure and soil.

Front 20

What is the name of the neurotoxin involved in the pathogenesis of tetanus?

Back 20

Tetanospasmin.

Front 21

Typical cases of tetanus cause with a small wound caused by a . . .?

Back 21

Splinter or a nail.

Front 22

What are the clinical manifestations of Tetanus?

Back 22

Incubation period: 4 days to weeks.
Masseter muscles often first affected: Inability to open mouth=“Lockjaw”
-Other muscles affected later:
Affects respiration and swallowing.

Front 23

Prevention of tetanus?

Back 23

Immunization:
-DPT shots at 2,4,6, and 18 months.
-Booster at age 6, then every 10 years.

Front 24

Clostridium botulinum Neurotoxins?

Back 24

-7 antigenically distinct toxins (A - G)
-Neurotoxins inhibit acetylcholine release causing muscular paralysis.
-Lethal dose < 1ug for humans
-Most human disease due to A, B, E strains
-Toxins A, B, E, are chromosomal
-Toxins are heat labile.
-Inactivated by boiling 10 minutes

Front 25

Food botulism is caused by?

Back 25

CANNED FOOD! (spores survive canning process)

Front 26

Clinical manifestations of Botulism?

Back 26

-Incubation period 18-96 hours.
-Dry mouth, difficulty swallowing.
-Double vision, pupils fixed and dilated.
-Difficulty walking and keeping balance.
-Difficulty breathing (muscles affected).
-Paralysis develops

Front 27

Infant botulism is also called?

Back 27

Floppy Baby Syndrome

Front 28

Infant botulism is caused by?

Back 28

-C. botulinum infection of infant colon
-Occurs up to 8 months of age
-Organism introduced in foods
-Solid foods or honey in milk.
-Immature normal flora does not limit multiplication of C. botulinum.
-Organism produces neurotoxin which is gradually absorbed into body

Front 29

Infant botulism clinical manifestations?

Back 29

Constipation; Poor muscle tone (floppy baby); Lethargy and feeding problems

Front 30

Diagnosis of Infant botulism?

Back 30

Test serum for toxin.

Front 31

Wound botulism is caused by?

Back 31

C. botulinum growing in wounds and produces neurotoxin.
Disease similar to food poisoning.

Front 32

Clostridium difficile general characteristics?

Back 32

An anaerobic spore forming Gram positive rod in the GI tract.

Front 33

Name the two toxins involved in C. difficile and what they do?

Back 33

Toxin A: Enterotoxin for entry into cell.
Toxin B: Most potent cytotoxin

Front 34

C. difficile is caused by?

Back 34

Antibiotic treatment with clindamycin especially (and also ampicillin) that eliminates the normal flora of the GI tract and allows C. difficile to grow out of control.

Front 35

The most serious condition caused by antibiotic induced C. difficile is?

Back 35

Pseudomembranous Colitis (C. difficile is responsible for nearly all cases)

Front 36

How does one treat C. difficile?

Back 36

First: Stop offending antibiotic which is altering the normal flora.
Second: antibiotic treatment with
Vancomycin or Metronidazole

Front 37

Control measures for C. diff?

Back 37

Early diagnosis is important
-Current lab tests miss 10-20% of cases. PCR or 4th generation immunoassays may improve this.
-Isolate patients to prevent spread of spores from diarrhea.
-Terminal cleaning of hospital rooms must be done with Clorox disinfectant.
-Wash hands with soap and water
DO NOT use alcohol gels which don’t kill spores.

Front 38

Name the Non-Spore Forming Gram-Positive Anaerobic Rods?

Back 38

More pathogenic members:
-Actinomyces
-Propionibacterium
Less pathogenic members:
-Mobiluncus (may help cause vaginitis)
-Lactobacillus
-Eubacterium
-Rothia

Front 39

Actinomyces israelii general characteristics?

Back 39

Long Gram positive rods; Often branching; No spores; not acid fast

Front 40

Bacteroides fragilis general characteristics?

Back 40

Gram-negative rod

Front 41

B. fragillis causes?

Back 41

Abdominal infection.

Front 42

What characteristics makes B. fragillis virulent?

Back 42

grows in bile, beta lactamase positive (resistant to penicillin), capsule with antiphagocytic functions

Front 43

Fusobacterium spp.?

Back 43

Spindle shape Gram negative rod.
Slow-growing colony.
Species
F. nucleatum: Most common of Genus

Front 44

Fusobacterium compared with B. fragillis?

Back 44

Compared to Bacteroides fragilis:
Fusobacteria are:
-Less virulent & less common.
-More difficult to grow.
-More sensitive to traces of oxygen.
-More sensitive to penicillin G