Chapter 2: Medically Relevant Bacteria

Question 1

Bacteremia

Answer 1

bacteria in bloodstream without overt clinical signs

Question 2

Septicemia

Answer 2

bacteria in bloodstream (multiplying) with clinical symptoms

Question 3

What medically relevant organisms commonly reside in the blood?

Answer 3

none, generally sterile

Question 4

What are medically relevant organisms that are found at cutaneous surfaces including urethra and outer ear?

Answer 4

Staphylococcus epidermidis

Question 5

What are some medically relevant organisms that commonly reside in the nose?

Answer 5

staphylococcus aureus

Question 6

Some medically relevant organisms that reside in the oropharynx?

Answer 6

Viridans streptococci including Streptococcus mutans

Question 7

How does Streptococcus mutans produce dental plaque?

Answer 7

secretes a biofilm that glues it and other oral flora to teeth producing dental plaque

Question 8

What are some less common but notable organisms found in the oropharynx?

Answer 8

Assorted streptococci, nonpathogenic Neisseria, nontypeable Haemophilus influenzae, Candida Albicans

Question 9

What does nontypeable Haemophilus mean?

Answer 9

Haemophilus that has no capsule

Question 10

What are some medically relevant organisms that are found in gingival crevices?

Answer 10

Anaerobes: Bacteroides, Prevotella, Fusobacterium, Streptococcus, Actinomyces

Question 11

What are some medically relevant organisms that are found in the stomach?

Answer 11

none

Question 12

What are some common or medically relevant organisms that reside in the colon?

Answer 12

microaerophilic/ anaerobic

Babies: breast fed only
Bifidobacterium

Adult:
Bacteroides/ Prevotella
(predominant organism)

Escherichia

Bifidobacterium

Question 13

What are some less common but notable organisms that can be found in the colon in babies?

Answer 13

lactobacillus, streptococci

Question 14

What are some medically relevant organisms that reside in the vagina?

Answer 14

lactobacillus

Question 15

What organisms colonize the vagina of 15-20% of women and may infect the infant during labor or delivery, causing septicemia and/or meningitis? What organism may infect the neonate from fecal flora?

Answer 15

Group B Streptococcus

E. coli from fecal

Question 16

Characteristics of obligate aerobes?

Answer 16

• require oxygen
• have no fermentative pathways
• generally produce superoxide dismutase

Question 17

Important genera found to be obligate aerobes?

Answer 17

• mycobacterium
• pseudomonas (bacillus)

Question 18

What are characteristics of microaerophilic organisms?

Answer 18

require low but not full oxygen tension

Question 19

What are some important genera considered microaerophilic organisms?

Answer 19

• Campylobacter
• Helicobacter

Question 20

Characteristics of facultative anaerobes?

Answer 20

Will respire aerobically until oxygen is depleted and then ferment

Question 21

Important genera of facultative anaerobes?

Answer 21

most bacteria, e.g., Enterobacteriaceae

Question 22

What are some important characteristics to remember about obligate anaerobes?

Answer 22

• lack superoxide dismutase
• generally lack catalase
• are fermenters
• cannot use O2 as terminal electron acceptor

Question 23

What are some genera that are considered obligate anaerobes?

Answer 23

• Actinomyces
• Bacteroides
• Clostridium

Question 24

How do you remember some of the most important obligate anaerobes?

Answer 24

ABC’s

• Actinomyces
• Bacteroides
• Clostridium

Question 25

What color do Gram + organisms stain? Why?

Answer 25

purple/blue Have large peptidoglycan layer so can absorb crystal violet better

Question 26

What color do Gram (-) bacteria turn with gram stain? Why?

Answer 26

red/ pink peptidoglycan layer is not as large so won't absorb crystal violet as well

Question 27

What color do acid fast organisms stain?

Answer 27

red

Question 28

What color do non-acid fast bacteria stain?

Answer 28

blue

Question 29

Another name for acid fast stain?

Answer 29

Ziehl-Neelson or Kinyoun stain

Question 30

All cocci are Gram negative or Gram positive with what exceptions?

Answer 30

Gram-positive with the exception of Neisseria, Moraxella, and Veillonella

Question 31

All spore formers are Gram negative or Gram positive?

Answer 31

Gram positive

Question 32

Background in stains modified for tissue will be what color?

Answer 32

red

Question 33

What are 2 protozoan parasites that have acid fast oocysts?

Answer 33

Cryptosporidium and Isospora

Question 34

List Gram negative cocci bacteria.

Answer 34

* Neisseria * Moraxella * Veillonella

Question 35

List major groups of Gram negative rods.

Answer 35

rods, curved or helical, enterobacteriaceae, anaerobic rods, gram-variable rods, spirochetes

Question 36

List gram negative rods.

Answer 36

* Pseudomonas * Burkholderia * Acinetobacter * Eikenella * Kingella * Haemophilus * Bartonella * Legionella * Brucella * Bordetella * Francisella * Capnocytophaga * Pasteurella

Question 37

List gram negative curved or helical rods.

Answer 37

* Campylobacter * Helicobacter * Vibrio

Question 38

List the organisms of the enterobacteriaceae family.

Answer 38

* Escherichia * Shigella * Salmonnella * Klebsiella * Proteus * Yersinia * Aeromonas * Serratia * Citrobacter * Enterobacter

Question 39

List the organisms considered gram negative anaerobic rods?

Answer 39

* Bacteroides * Prevotella * Porphyromonas * Fusobacterium

Question 40

List the gram-variable rods.

Answer 40

* Gardnerella * Mobiluncus

Question 41

List the spirochetes.

Answer 41

* Treponema * Borrelia * Leptospira

Question 42

List the Gram positive cocci.

Answer 42

Staphylococcus Streptococcus Enterococcus

Question 43

List the types of Gram positive rods (groups)?

Answer 43

* aerobic or facultative anaerobic * anaerobic

Question 44

What are the aerobic or facultative anaerobic gram positive rods?

Answer 44

* bacillus * listeria * corynebacterium * nocardia * mycobacterium

Question 45

What are the anaeorbic gram positive rods?

Answer 45

* clostridium * actinomyces * propionibacterium * lactobacillus

Question 46

Gram + spore formers?

Answer 46

Clostridium Bacillus

Question 47

What are 3 classes of non- Gram- staining bacteria?

Answer 47

* Mycoplasmataceae * Rickettsiaceae * Chlamydiaceae

Question 48

What are the organisms found in the Mycoplasmataceae family?

Answer 48

* Mycoplasma * Ureaplamsa

Question 49

What are some organisms found in the Rickettsiaceae family?

Answer 49

* Rickettsia * Ehrlichia * Coxiella

Question 50

What are some organisms found in the Chlamydiaceae family?

Answer 50

* Chlamydia * Chlamydophila

Question 51

Why does mycobacterium not stain well with gram stain? What is it technically considered (Gram negative or positive)

Answer 51

Waxy cell wall does not work well with gram stain; considered gram positive

Question 52

What organisms are so thin that the color of gram stain cannot be seen and are organisms that are all considered gram negative?

Answer 52

spirochetes, chlamydiae, and rickettsias

Question 53

What organisms that is Gram negative, does not stain well with traditional gram stain unless counterstain in increased?

Answer 53

Legionella