Actinomyces, Bacterioides, Fusobacterium

Question 1

Describe the following classes on bacteria based on O2 requirements:

Obligate anaerobe

Strict anaerobe

Moderate anaerobe

Facultative anaerobe

Answer 1

Obligate: kilt by normal O2 levels

Strict: dies at more than 0.5% O2 (e.g., Bacteroides, Clostridia)

Moderate: grows up to 8% O2 (e.g., Propionibacterium)

Facultative anaerobes: grow both in presence and absence of air (e.g. Enterobacteriaceae, S. aureus, Streptococcus)

Question 2

Which anaerobic bacteria would you find in the intestinal tract? (name 3 types)

Answer 2

Bacteriodes

Clostridia spp (clostra = pasta)

Anaerobic cocci (round candies written with a big NO for no oxygen on them)

Question 3

3 anaerobic bacteria you would find in the vagina include Prevotella, ___, and Peptostreptococcus

Answer 3

Prevotella (imagine using a vaginal cream called Prevotella)

Lactobacillus (vaginal secretions sometimes look kinda milky so there you go)

Peptostreptococcus (strep that likes peptobismal?)

Question 4

Which anaerobic bacteria would you find in the oral cavity? Name 3 (hint: one of them is also in the vagina)

Answer 4

Anaerobic gram positive cocci

Prevotella

Fusobacterium (fuso like you’re drinking an infusion - except of bacteria)

Question 5

Name 2 functions of anaerobic bacteria in the human body

Answer 5

Prevent colonization & infection by pathogens

Contribute to host physiology: e.g. Bacteriodes fragilis makes Vitamin K and deconjugates bile acids for us

Question 6

One way that anaerobic bugs can cause disease is to first create an anaerobic environment. Describe the ways in which they can do this

Answer 6

Mixed infection with facultative bacteria: the usual facultative bugs that cause serious infection and destroy tissue consume a lot of O2 in the process, which leaves an anaerobic environment behind for the anaerobes to thrive

Signal host cells to increase O2 consumption

Question 7

3 ways that anaerobes can evade host immunity include ___, inactivating complement and release of ___

Another way that anaerobic bacteria cause disease is to form an ___, mediated by a capsule that walls off the infection site

Answer 7

3 ways that anaerobes can evade host immunity include preventing phagocytosis, inactivating complement and release of toxins

Another way that anaerobic bacteria cause disease is to form an abscess, mediated by a capsule that walls off the infection site

Question 8

The presence of ___, tissue necrosis (gangrene), ___ and infection near a musocal surface can all clue you into an anaerobic infection

Answer 8

Foul odor

Gangrene

Presence of gas

Abscess

Infection near mucosal surface/ass’d w/ malignancy

Gram stain w/ multiple morphologies

Question 9

Name the gram +ve anaerobic cocci

Answer 9

Only one. Peptostreptococcus

Question 10

There are 4 non-spore forming types of gram +ve bacteria, including Propionibacterium (aka ___), ___, Lactobacillus and ___

Answer 10

Propionibacterium aka Cutibacterium: causes/ass’d with acne (propioni causes acne or since now its called cutibacterium, remember acne isn’t cute)

Actinomyces

Lactobacillus

Mobiluncus (like moby-dick)

**A Lame Man is not Cute**

Question 11

Which species of bacteria are gram +ve spore forming anaerobes?

Answer 11

Clostridium spp

Question 12

Name the gran -ve anaerobic cocci

Answer 12

Only one. Veillonella (almost sounds like violin)

Question 13

Gram negative anaerobic bacilli include ___, Fusobacterium, Prevotella and ___ (hint: the last one reminds you of the dreaded porphyrias)

Answer 13

Bacteroides (fragilis, thetaiotaomicron) **GI infections**

Fusobacterium. **Fusobacterium can cause oral infection**

Prevotella

Porphyromonas

Question 14

Anaerobic bacteria can also be classified as endogenous or exogenous. Define this classification

Answer 14

Endogenous. Its on you and its in you normally, and is ass’d with abscesses

Exogenous. The exogenous bugs are generally Clostridia (b/c #spores). Can be inoculated or acquired from external environment and cause toxin-mediated disease

Question 15

Where in/on the body do you find Peptostreptococcus?

What kinds of infections could be caused by this bug?

How do you Rx infections caused by this bug?

Answer 15

Found on skin and mucosal surface

Polymicrobial infections:

Sinusitis, pleuropulmonary infections, brain abscesses

Intraabdominal infections

Endometritis, pelvic abscesses

Soft tissue infection

Rx: Penicillin but in combo with a beta-lactamase inhibitor

Question 16

Where on/in the body do you anaerobic, non-spore forming gram +ve rods?

Answer 16

Found on all mucosal surfaces; Cutibacterium (Propionibacterium) also found on skin (esp hair follicles)

**note that these grow slowly**

Question 17

____ causes actinomycosis, which is characterized by chronic infection w/ relapsing/remitting course associated with ___, draining sinuses, ___

One feature of this infection is that it ___, which is how it can sometimes be mistaken for malignancy

Answer 17

Actinomyces israelii causes actinomycosis, which is characterized by chronic infection w/ relapsing/remitting course associated with abscess, draining sinuses, fibrosis

Crossing tissue planes: basically the infection spreads from tissue to tissue; part of the reason why it can also be mistaken for malignancy

Question 18

Actinomyces can grow when there is ___ of the mucosal barrier

Answer 18

Disruption (remember in the sketchy video that this bug is ass’d with jaw trauma/dental surgery)

Question 19

Which bug causes the pathology below? Name the pathology

Answer 19

Actinomyces_israelii

Question 20

Who bug this is?

Answer 20

Actinomyces

Question 21

How would you treat Actinomyces infection?

Answer 21

Penicillin G or amoxicillin

Also use tetracyclines and carbapenems (metronidazole don’t work in these bugs)

Question 22

Lactobacillus can cause sepsis in ___ patients, and ___ in pts with pre-existing valve abnormalities

Answer 22

May cause sepsis in immunocompromised patients

May cause endocarditis in persons with underlying valve abnormalities

Question 23

Who bug is this?

Answer 23

Lactobacillus

Question 24

Cutibacterium is responsible for which skin issue? It can also cause invasive infections in patients with___

Answer 24

Acne

Indwelling foreign bodies (prosthetics, esp prothetic shoulders, indwelling catheters) (also neurosurgical infections)

**Apparently this bug really likes the head and neck region. The hair follicles and sebaceous glands in the head and neck region as well as those in the axilla are densely colonized with Cutibacterium**

Question 25

Who bug is this?

Answer 25

Cutibacterium

Question 26

How do you treat Cutibacterium infection? (like the serious ones)

Answer 26

benzoyl peroxide (topical) or tetracycline or clindamycin for acne, penicillin/beta-lactams, vancomycin for systemic disease

Question 27

Who bug is this and what infection is this thing ass’d with?

Answer 27

Mobiluncus (found on epithelial cell borders obscured by the bugs)

Ass’d with bacterial vaginosis

Question 28

How would Rx Lactobacilli infection?

Answer 28

penicillin or combination of antibiotics (e.g., penicillin plus an aminoglycoside); bacteria resistant to vancomycin

Question 29

___ is a gram -ve anaerobic rod which can cause GI infections since its a major component of the colonic flora

Answer 29

Bacteroides fragilis

Question 30

Bacteroides fragilis has LPS but lacks ___ activity. Its main virulence factor is a __ which prevents phagocytosis and promotes abscess formation

Answer 30

Bacteroides fragilis has LPS but lacks endotoxin activity. Its main virulence factor is a polysaccharide capsule which prevents phagocytosis and promotes abscess formation

**Note also the other virulence factors, and that its catalase and SOD positive**

Question 31

Bacteroides fragilis infection is mainly characterized by ___ infections

How would you treat infections caused by this bug?

Answer 31

Bacteroides >> intraabdominal abscesses!!!

Other diseases caused by this bug:

pelvic inflammatory disease and endometritis

surgical wound infections

skin and soft tissue infections after surgery or trauma

Rx: beta-lactam/beta-lactamase inhibitor OR metronidazole plus antibiotics active against other organisms in infection

**know that this guy has a beta lactamase so it resistant to beta lactam antibiotics if you give them sans an inhibitor**

Question 32

Who bug is this?

Answer 32

Bacteroides fragilis

Question 33

Fusobacterium nucleatum is part of the normal flora of the ___, GI and genitourinary tracts

This bug mostly causes ___ infections, including infections of the head and neck

Answer 33

Part of normal flora of oropharynx, GI and genital tracts

Oropharyngeal infections:

Acute necrotizing ulcerative gingivitis (“trench mouth”)

Pharyngitis, tonsillitis (Vincent’s angina)

Jugular venous thrombophleitis (Lemierre’s syndrome)

Question 34

Who bug is this?

Answer 34

Fusobacterium

Question 35

Fusobacterium can cause ___ infections (hint: head and neck and tooth related)

Answer 35

Odontogenic infections: dental related infections of the head and neck

Question 36

___ syndrome is classically caused by fusobacterium and results in thrombophlebitis of the internal jugular vein

How does this syndrome progress?

Answer 36

Lemierre’s syndrome is classically caused by fusobacterium and results in thrombophlebitis of the internal jugular vein

Pharyngitis >> peritonsillar abscess >> spread of bacteria through pharyngeal spaces >> thrombophlebitis of internal jugular vein

(clots can end up lodging in the lungs or other organs and cause disease there)

Question 37

How do you treat Fusobacterium infections?

Answer 37

Beta lactam/beta-lactamase inhibitor

Question 38

T/F: Cat bites are more likely to produce infection than dog bites (but you should treat empiracally in case of an animal bite anyway)

Answer 38

True