Micro - Acid Fast and Bacteria Without Cell Walls

Question 1

tuberculosis

Answer 1

mycobacterium tuberculosis

Question 2

leprosy

Answer 2

mycobacterium leprae

Question 3

rods with acid-fast staining

Answer 3

mycobacteria

Question 4

acid-fast organism

Answer 4

mycobacteria

nocardia

Question 5

acid-fast stain

Answer 5

smear of sputum covered with red carbolfuchsin and heated

• acid alcohol poured over
• methylene blue counterstained
• cell wall lipids don’t dissolve - so red stain holds
• not acid fast - turn blue

Question 6

1/3 of HIV patients

Answer 6

also harbor mycobacterium tuberculoid

Question 7

mycosides

Answer 7

class of lipid in acid-fast organisms

mycolic acid bound to carbohydrate

Question 8

cord factor

Answer 8

mycoside formed by union of two mycolic acids with a disaccharide

inhibits neutrophil migration and damages mitochondria

Question 9

tuberculosis

Answer 9

chronic disease - associated with weight loss

-can be confused with cancer

Question 10

sulfatide

Answer 10

mycoside that resemebles cord factor with sulfates attached to disaccharide

Question 11

wax D

Answer 11

complicated mycoside

Question 12

caseous necrosis

Answer 12

in tuberculosis

-due to cell-mediated immunity destroying infected lung tissue

Question 13

PPD skin test

Answer 13

for mycobacterium tuberculosis
-reveal whether individual has been infected

-positive test - latent TB

> 5mm - HIV positive or immunosuppressed
10mm - common risk factors for exposures
15mm - all other individuals

Question 14

false positive PPD test

Answer 14

if individual had BCG vaccine

Question 15

false negative PPD test

Answer 15

some patients do not react to PPD even if infected

Question 16

asymptomatic primary tuberculosis

Answer 16

bacteria walled off in caseous granulomas

calcified tubercle in middle or lower lung zone - ghon focus

Question 17

symptomatic primary tuberculosis

Answer 17

children, elderly, immunocompromised

• enlarged mediastinal or hilar lymph nodes
• untreated - leads to cavities in lung (necrosis)

cavitary lesions with air-fluid levels

Question 18

secondary tuberculosis

Answer 18

-pulmonary - most common site - chronic low grade fever, night sweats, weight loss, productive cough

pleural/pericardial - fluid collection around lung or heart

lymph node - cervical common - swollen, mat together, and drain - scrofula

kidney - sterile pyuria - red and white blood cells in urine

skeletal - potts disease

joints - chronic arthritis of one joint

CNS - subacute meningitis - granulomas in brain

miliary - granulomas all over body

Question 19

potts disease

Answer 19

IV discs and vertebral bodies destroyed in secondary tuberculosis

Question 20

Gene Xpert MTB/RIF

Answer 20

easy, fast, reliable diagnosis of tuberculosis

but expensive

Question 21

MDR and XDR tuberculosis

Answer 21

multi-drug and extremely-drug resistant

Question 22

TB rule of fives

Answer 22

5 % risk of reactivation
high five (HIV) 5 + 5% risk of reactivation per year
droplet nuclei - 5 micrometers

Question 23

hansens disease

Answer 23

leprosy

caused by mycobacterium leprae

grows in cool areas of body - damages skin, nerves, eyes, nose, testes

Question 24

lepromatous leprosy

Answer 24

severest form

• skin lesions cover entire body
• leonine facies - thickened skin of face
• saddle nose deformity
• testicular damage
• blindness
• loss of sensation in extremities in glove distribution

Question 25

tuberculoid leprosy

Answer 25

can mount cell-mediated response
-contain skin damage

-localized superficial, unilateral skin, and nerve involvement

1 or 2 skin lesions
-well-defined hypopigmented elevated blotches

Question 26

single skin lesion, no hair growth on lesions, loss of sensation or extremities, no acid fast bacilli in skin scraping, positive lepromin skin test

Answer 26

tuberculoid leprosy

Question 27

lepromin skin test

Answer 27

measures ability of host to mount delayed hypersensitivity response against myocbacterium leprae

Question 28

nontuberculous mycobacterium

Answer 28

AIDs patient with disseminated MAC disease

-unexplained fever, weight loss, diarrhea, malaise, elevation fo alkaline phosphatase

Question 29

most common cause of nontuberculous mycobacterium lung disease

Answer 29

MAC

• upper lung cavitary disease - male smokers
• lower and middle lung with bronchiectasis and nodular infiltrates in middle-aged non-smoking women

Question 30

smallest free-living organisms capable of self-replication

Answer 30

mycoplasma

• no peptidoglycan wall
• cell membrane with sterol
• can contort shape

Question 31

walking pneumoniae

Answer 31

mycoplasm pneumoniae
-gradual onset of fever, sore throat, malaise, persistent dry hacking cough

patients don’t feel very sick

Question 32

number one cause of bacterial bronchitis and pneumonia in teenagers and young adults

Answer 32

mycoplasma pneumoniae

Question 33

stevens-johnson syndrome

Answer 33

severe skin reaction with erythematous vesicles in mucocutaneous junctions of mouth, eyes, skin

mycoplasm pneumoniae

Question 34

cold agglutinins

Answer 34

monoclonal IgM Abs against RBC antigens
-cause them to aggllutinate

in patients infected with mycoplasm pneumoniae

Question 35

test for cold agglutinins

Answer 35

patient blood in tube

• put in ice - blood will clump
• when warmed up - will unclump

Question 36

T-strain mycoplasm

Answer 36

ureaplasma urealtyticum

breaks down urea

normal flora in sexually active women
-causes lower urinary tract infection - urethritis

can metabolize urea into ammonia and CO2

Question 37

no cell wall

Answer 37

mycoplasm pneumoniae

ureaplasma urealyticum