Anaerobic Gram Negative Bacteria

Question 1

_________ are the predominant bacterial microbiota on the mucous membranes of the human respiratory tract, gastrointestinal tract, and genitourinary tract.

Answer 1

anaerobes

Question 2

The majority of anaerobic infections are cuased by microbiota that become _______ pathogens.

Answer 2

opportunistic

Question 3

Infections with anaerobes occur in settings of reduced ________ potential in tissues that re normally well-oxygenated and therefore resistant to invasion by anaerobes.

Answer 3

oxidation-reduction

Question 4

Reduced oxidation-reduction potential in tissues in caused by what?

Answer 4

impaired blood supply, tissue necrosis, etc.

Question 5

Anaerobic microbiota gain access through breaks in _______.

Answer 5

mucosal epithelium

Question 6

Breaks in mucosal epithelium are caused by what?

Answer 6

surgery, trauma, cancer, etc.

Question 7

What is the end result of anaerobic pathogenesis?

Answer 7

localized tissue destruction and inflammation

Question 8

Name 6 clinical characteristics of anaerobic infections.

Answer 8

• foul smelling discharge
• infection close to mucosal surfaces
• tissue necrosis
• gas in tissues
• infection related to use of antibiotics that have poor activity against anaerobes (e.g. aminoglycosides)
• infection following human or animal bites

Question 9

What are normally beneficial endogenous residents but when displaced by trauma or disease to sterile sites or fluids such as subcanteous pleuropulmonary, intraabdominal, or genital tissues?

Answer 9

gram negative anaerobes

Question 10

Many _____ form biofilms and rely on helper organisms?

Answer 10

gram negative anaerobes

Question 11

True or False? Biofilms are sometimes mixed infections (anaerobes and facultative species).

Answer 11

False. They are always mixed infections.

Question 12

What are the two ways in which biofilms increase pathogenecity?

Answer 12

• allowing transfer of genes between residents

- strongly resisting antimicrobial agents

Question 13

True or False? Virulence is often intensified when co-infections by certain species exist?

Answer 13

True

Question 14

When virulence is intensified by co-infections by certain species, it is referred to as ________.

Answer 14

synergistic enhanced virulence

Question 15

What species is Gm- baciili, obligate anaerobe, non-endospore forming, with some motile and others not?

Answer 15

bacteriodes species

Question 16

What type of pathogen is bacteriodes species?

Answer 16

opportunistic pathogen

Question 17

Bacteriodes species, such as _______, are major inhabitants of the human colon.

Answer 17

B. fragilis

Question 18

Bacteriodes species may invade tissues through wounds in what area?

Answer 18

intestinal mucosa (cancerous lesions, surgical, wounds, etc.)

Question 19

Once bacteriodes enter the tissue they form an ______.

Answer 19

abscess

Question 20

What is a localized mass of bacteria and pus contained in a cavity of dead tissue?

Answer 20

abscess

Question 21

True or False? The interior of the abscess is aerobic and generally impenetrable to antibiotics.

Answer 21

False, the interior is aerobic

Question 22

What 3 virulence factors allow for tissue destruction and ultimately abscess formation?

Answer 22

lipases, proteases, and collagenases

Question 23

What are 5 diseases caused by bacteriodes species?

Answer 23

intra-abdominal abscesses
pressure ulcers
appendicitis
abscess formation in female genital tract
bacteremia

Question 24

What is bacteriodes species diagnosed?

Answer 24

The organism is cultured on bile-esulin agar. If the specimen contain bacteriodes, the media will become dark brown in areas surrounding the growth.

Question 25

What bacteria is gm- bacilli, obligate anaerobe, non-endospore forming, and non-motile?

Answer 25

Prevotella species

Question 26

What bacteria colonizes the human mouth, vagina, and gastrointestinal tract?

Answer 26

Prevotella species and Fusobacterium species

Question 27

What 6 diseases can be caused by Prevotella species?

Answer 27

abscesses
aspiration pneumonia
bacteremia
wound infections
urinary tract infections
periodontitis

Question 28

What virulence factor destroys white blood cells?

Answer 28

leukotoxin

Question 29

What virulence factor destroys red blood cells?

Answer 29

hemolysis

Question 30

What virulence factor mediates host tissue destruction?

Answer 30

phospholipase C

Question 31

What diseases is characterized by complication of a throat infection that leads to inflammation of internal jugular vein?

Answer 31

Lemierre syndrome

Question 32

What bacteria species causes Lemierre syndrome?

Answer 32

Fusobacterium species

Question 33

What 6 diseases are caused by fusobacterium species?

Answer 33

Lemierre syndrome
peritonsilar abscess
intra-abdominal infections
pulmonary infections
wound infections

Question 34

What is the most common species to cause disease in humans?

Answer 34

Porphytomonas species (P. gingivalis)

Question 35

What bacterium colonizes mouth (resides below gingival surface), respiratory tract, gastrointestinal tract?

Answer 35

Porphyromonas species

Question 36

What disease is caused by P. gingivalis?

Answer 36

chronic adult periodontitis

Question 37

All B. fragilis-like species and many Prevotella and Porphyromonas species such as Fusobacteria isolates produce what virulence factor?

Answer 37

Beta-lactamase