Exam 2 Lecture 15

Question 1

True or false: Mycoplasma and Ureaplasma spp are relatively easy to grow/culture

Answer 1

False: they are fastidious

Question 2

M. pneumoniae primarily causes what type of infections?

Answer 2

Middle/lower respiratory tract infections

Question 3

Which Mycoplasma species cause GU infections?

Answer 3

M. hominis & M. genitalium

Question 4

True or false: M. hominis & M. genitalium are primarily GU organisms, but they can disseminate to the lungs.

Answer 4

True

Question 5

Ureaplasma are similar to M. hominis and M. genitalium in that they typically cause:

Answer 5

GU infections

Question 6

Describe Mycoplasma ultrastructure

Answer 6

not a typical appearance for a bacterial cell wall: 3 layers, no peptidoglycan (no cell wall)

Question 7

Since Mollicutes do not have a cell wall, what does this imply about Tx?

Answer 7

we can’t use cell wall antibiotics (vancomycin, beta lactams) because they don’t have peptidoglycan

Question 8

Size/shape of M. pneumoniae

Answer 8

Tapered rods, 1-2 x 0.2 microns (tiny)

Question 9

Size/shape of M. hominis

Answer 9

Coccoid, 0.2-0.3 microns (smaller than M. pneumoniae)

Question 10

Size/shape of Ureaplasma spp

Answer 10

Coccoid, 0.2-0.3 microns (same as M. hominis)

Question 11

What does a small genome imply for the Mollicutes?

Answer 11

less flexibility for LOF mutations since they have lost their own metabolism pathway genes; depend on host cell for growth/replication

Question 12

When Mollicutes are grown on medium, what do we see?

Answer 12

Colonies aren’t immediately visible, very small, fried-egg appearance

Question 13

How long does it take to grow M. pneumoniae in lab?

Answer 13

several weeks

Question 14

How long does it take to grow M. hominis & Ureaplasma in lab?

Answer 14

2-4 days

Question 15

True or false: culture is the best/primary method to detect Mollicutes

Answer 15

false: takes a long time + risk of false negatives

Question 16

M. pneumoniae typically causes diseases such as?

Answer 16

bronchitis (tracheobronchitis); pneumonia (CAP)

Question 17

What is the age group that is most at risk for M. pneumoniae infections?

Answer 17

5-17 y.o. (school age kids + adolescents)

Question 18

There are typically _____ cases/year of pneumonia caused by M. pneumoniae

Answer 18

~ 100,000

Question 19

True or false: M. pneumoniae infections are becoming increasingly nosocomial acquired

Answer 19

False: more community acquired

Question 20

____ infections can occur with M. pneumoniae

Answer 20

Recurrent

Question 21

What are some extrapulmonary infections of M. pneumoniae?

Answer 21

encephalitis, dermatitis, SJS

Question 22

Encephalitis is typically ____-acquired and occurs in __. Symptoms include:

Answer 22

hospital; kids; acute psychiatric symptoms, rarely stroke

Question 23

If extrapulmonary, M. pneumoniae commonly causes ____ and ____ ____

Answer 23

SJS (dermatidites); cold agglutinin

Question 24

What is SJS?

Answer 24

Stevens-Johnson Syndrome; auto-immune mediated necrolisis of skin involving mucous membranes + epidermis

Question 25

M. pneumoniae adhesin is called __ ____, and is important for ____ ____

Answer 25

P1 adhesin; glidiing motility

Question 26

M. pneumoniae produces ___ ___, which is another bipartite toxin

Answer 26

CARDS toxin

Question 27

Other Mycoplasma and Ureaplasma diseases include: (lots)

Answer 27

1. upper urinary tract infections 2. non-gonococcal urethritis 3. cervicitis, salpingitis, endometritis, PID 4. post-partum fever 5. congenital/neonatal infections 6. septic arthritis 7. bacteremia 8. meningitis, osteomyelitis, wound infx

Question 28

Ureaplasma virulence factors

Answer 28

1. IgA protease 2. Urease 3. multiple adhesins (poorly characterized) 4. MB (major antigen from host perspective)

Question 29

Lab detection (2)

Answer 29

* we rely on molecular methods since Cx is tough * 1. PCR (good but not great, 40% sensitivity in early infx) 2. Serology for M. pneumoniae (4-fold change in titer is significant)

Question 30

Mycoplasma and Ureaplasma Treatment

Answer 30

- emperic antibiotics for outpatient PNA | - usually azithromycin, levo/moxifloxacin, oral tetracycline

Question 31

Is there a vaccine available for Mycoplasma/Ureaplasma?

Answer 31

no

Question 32

True or false: for M. hominis infection, usually we use doxycycline to prevent abx increased resistance

Answer 32

true

Question 33

Legionella characteristics

Answer 33

- fastidious - bacillus - gram-negative but poor staining

Question 34

L. pneumophila is transmitted via ___

Answer 34

water supply (environmental transmission)

Question 35

L. pneumophila life cycle

Answer 35

1. often lives in amoeba bc it's a facultative parasite | 2. multi-organism biofilm growth in water supplies

Question 36

How does L. pneumophila cause disease in humans?

Answer 36

transmitted through aerosolized water, inhalation, then invades phagocytes

Question 37

Legionella are ___ to grow than Mollicutes, but needs ____-____ agar.

Answer 37

easier; charcoal-containing

Question 38

Describe L. pneumophila gram stain

Answer 38

gram negative, filamentous bacilli (but coccobacillary in humans)

Question 39

what do L. pneumophila colonies look like when cultured

Answer 39

grey-white, round/convex

Question 40

Legionella are ____ ____, ____, and ____.

Answer 40

obligate aerobes; fastidious; asacharolytic (in vitro)

Question 41

Asacharolytic

Answer 41

do not derive energy from sugars, instead they catabolize amino acids

Question 42

All Legionella spp require ____

Answer 42

L-cysteine

Question 43

____ is important for Legionella pathogenesis

Answer 43

iron acquisition system or siderophore

Question 44

For Legionella cultivation, use ___ ___ ___ ___

Answer 44

Buffered Charcoal Yeast Extract (BCYEalpha)

Question 45

What environmental conditions are best for Legionella growth

Answer 45

1. 35-37ºC 2. pH 6.7-6.9 (generally lower pH) 3. also salt sensitive

Question 46

Legionella Lab detection

Answer 46

1. Urine antigen testing for L. pneumophila serogroup 1 ONLY (!!) 2. PCR 16S rDNA (helpful for dif serogroup) 3. report to public health labs

Question 47

Legionnaire's Disease usually caused by ___ ___

Answer 47

serogroup 1

Question 48

Legionnaire's Disease characterizations

Answer 48

1. bacterial pneumonia acquired from aerosolized water 2. 18k cases/year in US 3. systemic symptoms like headache, muscle ache, loss of appetite, fever

Question 49

Legionnaire's Disease treatment

Answer 49

erythromycin, tetracycline, other drugs higher CFR

Question 50

Besides Legionnaire's Disease , L. pneumophila can also cause ___ ___

Answer 50

pontiac fever

Question 51

Legionnaire's Disease is ___ attack rate, ___ mortality

Answer 51

low, high

Question 52

Pontiac fever characterizations

Answer 52

1. upper respiratory infection, not pneumonia 2. high attack rate, non fatal 3. symptoms within 4-60 hrs exposure 4. cough, fever, loss of appetite, aches, belly pain, increased HR 5. more so inflammatory response than actual infection