Micro: Gram + Bacterial Infections

Question 1

Gram + cocci we will discuss can be grouped into two genera:

Answer 1

Staphylococci & Streptococci

Question 2

Gram + bacilli we will discuss can b grouped into two categories:

Answer 2

Spore forming & non-spore forming

Question 3

Name the Gram +, spore forming aerobic/facultative anaerobic genus

Answer 3

Bacillus

Question 4

Name the Gram +, spore forming obligate anaerobic genus

Answer 4

Clostridia

Question 5

Name the Gram +, non-spore forming, aerobic or facultative anaerobic genera

Answer 5

Corynebacteria & Listeria

Question 6

Staphylococci are found in what microscopic morphology?

Answer 6

Grape-like clusters

Question 7

Streptococci are found in what microscopic morphology?

Answer 7

chains/pairs and chains

Question 8

List the species of Staph we will discuss.

Answer 8

S. aureus
S. epidermidis
S. saprophyticus

Question 9

Streptococcus pyogenes are a group A, group B or group D Strep species?

Answer 9

Group A

Question 10

Streptococcus agalactiae are a group A, group B or Group D Strep species?

Answer 10

Group B

Question 11

Enterococci & Streptococcus gallolyticus are a group A, group B or Group D Strep species?

Answer 11

Group D

Question 12

Are S. aureus coagulase + or -?

Answer 12

Positive

Question 13

Where are S. aureus colonizers?

Answer 13

Skin and mucosa

Question 14

List the 3 clinical manifestations of S. aureus.

Answer 14

1- Pyogenic infections (boils/abscesses, folliculitis, wound infections, impetigo)
2- Disseminated infections (endocarditis, osteomyelitis, pneumonia (Hosp. acq), bacteremia/sepsis
3- Toxigenic (food poisoning, Toxic Shock syndrome, scalded skin syndrome)

Question 15

List the 3 broad categories of S. aureus virulence factors.

Answer 15

Surface proteins, enzymes, toxins

Question 16

T/F: antibiotic resistance is a common and worrisome feature of S. aureus infections.

Answer 16

Truth

Question 17

What is the cause of most Staph epidermidis infections?

Answer 17

occur in the setting of foreign devices (prosthetic joints/other ortho hardware, central lines, artificial valves, etc.)

Question 18

What helps Staph epi adhere to foreign objects?

Answer 18

Surface adhesins; BIOFILM (slime) is then produced which encases bacteria shielding them from Abx and immune response

Question 19

Staphylococcus saprophyticus is normal flora of the female ___________ and ___________.

Answer 19

genital tract; GI tract

Question 20

Are Staph epi & Staph saprophyticus coagulase - or +?

Answer 20

Negative

Question 21

What is the 2nd most common cause of UTIs behind E. coli?

Answer 21

Staph saprophyticus

Question 22

What is the Lancefield antigen?

Answer 22

carbohydrate antigen important for typing, especially for the beta-hemolytic Streps.
Groups A, B, C, D, & G refer to Lancefield antigen

Question 23

Describe alpha, beta and gamma hemolysis.

Answer 23

A- green blood agar around colonies
B- complete clearing of blood agar (group A & B Strep)
G- No change to BAP

Question 24

Describe the hemolysis of Strep pyogenes

Answer 24

Beta hemolytic

Question 25

Describe the Lancefield antigen of Strep pyogenes

Answer 25

Group A

Question 26

List the virulence factors of Strep pyogenes.

Answer 26

M protein, streptokinase, several different toxins

Question 27

What pyogenic diseases does S. pyogenes cause?

Answer 27

Pharyngitis, cellulitis, impetigo, necrotizing fasciitis, erysipelas

Question 28

What toxigenic diseases does S. pyogenes cause?

Answer 28

Scarlet fever, Toxic Shock Syndrome (TSS)

Question 29

What immune related diseases does S. pyogenes cause?

Answer 29

Rheumatic fever, acute glomerulonephritis

Question 30

Which group of Strep causes "Strep throat" (pharyngitis)?

Answer 30

Group A

Question 31

Describe the microscopic morphology of Strep pneumoniae

Answer 31

Lancet shaped diplococci

Question 32

Describe the hemolysis of Strep. pneumoniae

Answer 32

Alpha hemolytic

Question 33

List the diseases associated with Strep pneumoniae (more common in young, old and immunocompromised)

Answer 33

Lobar pneumonia Bacteremia Meningitis (most common cause) Otitis media (most common cause)

Question 34

Name the one virulence factor of Strep pneumoniae

Answer 34

Capsule

Question 35

Is there a vaccine for Strep pneumoniae?

Answer 35

Yes.

Question 36

What are the two genera/species of group D Strep?

Answer 36

Enterococcus sp. & Strep gallolyticus

Question 37

Enterococcus sp of Strep is a part of normal _______ flora.

Answer 37

Colonic flora

Question 38

Enterococcus is associated with these diseases:

Answer 38

Hospital-acquired UTIs Blood stream infections Endocarditis

Question 39

There is a very strong association between pts with colon cancer and Streptococcus gallolyticus induced ___________.

Answer 39

Endocarditis

Question 40

There are two forms of anthrax caused by Bacillus anthracis. List them and what causes their symptoms.

Answer 40

Inhalation anthrax and Cutaneous anthrax (most common form) | Both are toxin-mediated (AB toxin)

Question 41

Which gram positive rod causes food poisoning?

Answer 41

Bacillus cereus. Can be diarrheal or emetic, both toxin-mediated.

Question 42

List the 4 species of Clostridia.

Answer 42

C. perfringens C. difficile C. tetani C. botulinum

Question 43

C. perfringens causes what two diseases?

Answer 43

Gas gangrene (alpha toxin) & food poisoning (toxin) 3rd most common food-borne illness

Question 44

________ (genus & species) is the most common cause of nosocomial diarrhea and most common cause of abx-associated diarrhea.

Answer 44

C. difficile

Question 45

How does one contract C. dif?

Answer 45

Fecal-oral route

Question 46

T/F: C. diff's disease is toxin mediated.

Answer 46

true

Question 47

Where do you find the spores of C. tetani?

Answer 47

soil

Question 48

C. tetani's disease is _______-mediated. Surprise!

Answer 48

Toxin-mediated

Question 49

Infection with ___________ (genus & species) presents as strong muscle spasms and spastic paralysis (lock-jaw).

Answer 49

C. tetani

Question 50

What's the prognosis for a C. tetani infection?

Answer 50

Not good, high mortality. Vaccine is protective against toxin (TdaP, DTap).

Question 51

C. botulinum causes botulism, a _______-mediated disease.

Answer 51

Toxin-mediated. Almost got you!

Question 52

Floppy baby syndrome is caused by: (genus/sp)

Answer 52

Clostridium botulinum

Question 53

What is the 2nd most common cause of botulism?

Answer 53

Food-borne botulism

Question 54

What are the clinical manifestations of botulism?

Answer 54

hypotonia/difficulty feeding/weakness; flaccid paralysis

Question 55

Describe the microscopic morphology of Corynbacterium diptheriae. Do it now.

Answer 55

Pleomorphic (size/shape changes in response to env. conditions), club-shaped, arranged in palisades (chinese characters), beaded appearance.

Question 56

Guess, just GUESS what mediates Corynbacterium diptheriae disease!

Answer 56

AB Toxin you silly goose!

Question 57

Describe the disease caused by Corynbacterium diptheriae.

Answer 57

Acute pharyngitis with formation of an overlying gray membrane (pseudomembrane) which can cause mechanical obstruction

Question 58

What is the prophylactic vaccine for C. diptheriae?

Answer 58

DTap/TDaP

Question 59

Listeria monocytogenes causes these diseases in the extremes of age and in immunocompromised patients?

Answer 59

meningitis, bacteremia

Question 60

Infection in pregnancy with this bacterium can be devastating- nonspecific flu-like symptoms that can ultimately lead to fetal demise,/miscarriage/infection at birth.

Answer 60

Listeria monocytogenes

Question 61

If you see chinese language looking bacteria under a microscope, what is it?

Answer 61

Corynbacterium diptheriae

Question 62

T/F: Group A Strep is ALWAYS susceptible to Penicillins.

Answer 62

True

Question 63

Impetigo caused by group A strep will have what character and can be found where on the body?

Answer 63

Small, scabbed lesions. Around the mouth.

Question 64

Impetigo caused by S. aureus will have what character and be found where on the body?

Answer 64

More blister like, more bulbous. Found all over the body.

Question 65

Clostridium perfringens has a unique micro morph for a gram + bacterium. Describe it.

Answer 65

large "box-car" rods