pathology 8 (362-385) bacterial infections

Question 1

describe the stain and shape of staphylococcus

Answer 1

pyogenic gram positive cocci that form clusters resembling bunches of grapes

Question 2

what type of staphylococcus can cause UTIs in women

Answer 2

S. saprophyticus

Question 3

what does protein A of staphylococcus do

Answer 3

binds the Fc portion of immunoglobulins, allowing the organisms to escape antibody-mediated killing

Question 4

what does alpha toxin of S. aureus do

Answer 4

protein that intercalates into the plasma membrane of host cells, forming pores that allow toxic levels of calcium to leak into cells

Question 5

what do the exfoliative A and B toxins produced by S.aureus do

Answer 5

serine proteases that cleave the desmosomal protein desmoglein 1, which holds epidermal cells tightly together

Question 6

what do the super antigens produced by S. aureus cause

Answer 6

food poisoning and TSS

Question 7

what, besides S. aureus, can cause TSS

Answer 7

Streptococcus pyogenes

Question 8

what is another name for staphylococcal scalded-skin syndrome

Answer 8

ritter disease

Question 9

what type of infections do streptococci cause

Answer 9

suppurative infections

Question 10

describe the shape of streptococci

Answer 10

gram positive cocci that grow in pairs or chains

Question 11

what diseases does S. pyrogenes cause

Answer 11

pharyngitis, scarlet fever, erysipelas, impetigo, rheumatic fever, TSS, and glomerulonephritis

Question 12

how do enterococci grow

Answer 12

gram positive cocci that grow in chains

Question 13

how does S. mutans cause dental caries

Answer 13

by metabolizing sucrose to actin acid and by secreting high-molecular weight gluons that promote aggregation of bacteria and plaque formation

Question 14

what is the emergence of enterococci as pathogens primarily due to

Answer 14

resistance to antibiotics

Question 15

what is erysipelas caused by

Answer 15

exotoxins from superficial infection with S. pyogenes

Question 16

what is diphtheria caused by

Answer 16

corynebacterium diphtheriae

Question 17

describe the stain and shape of corynebacterium

Answer 17

slender gram positive rod with clubbed ends

Question 18

what blocks host cell protein synthesis with C. diptheriae

Answer 18

phage-encoded A-B toxin

Question 19

what finding in CSF is virtually diagnostic for L. monocytogenes infections

Answer 19

gram positive, mostly intracellular bacilli in the CSF

Question 20

what is anthrax characterized by

Answer 20

necrotizing inflammatory lesions in the skin or GI tract or systemically

Question 21

describe the shape and stain of bacillus anthrax

Answer 21

large, spore-forming gram positive rod-shoed bacterium found in environmental sources

Question 22

which subunit of the toxin is toxic for anthrax

Answer 22

A subunit

Question 23

what does EF of anthrax bind to in the cytoplasm

Answer 23

calcium and calmodulin to form adenylate cyclase

Question 24

what does LF of the toxin of anthrax do

Answer 24

protease that destroys MAPKKs

Question 25

what histologic finding is most indicative of anthrax

Answer 25

presence of large, boxcar-shaped gram positive extracellular bacteria in chains

Question 26

where are nocardia found

Answer 26

gram positive bacteria found in soil that appear in branching filaments

Question 27

what type of stain do nocardia stain with

Answer 27

modified acid-fast stain (fite-faraco stain)

Question 28

what can N. gonorrheae infection in men cause

Answer 28

urethritis

Question 29

what does the long pili of N. gonorrheae bind to

Answer 29

CD46 (protein expressed on all human nucleated cells)

Question 30

what bacteria causes pertussis/whooping cough

Answer 30

bordetella pertussis (gram negative coccobacillus)

Question 31

how is the diagnosis of pertussis made

Answer 31

PCR

Question 32

what does B. pertussis colonize

Answer 32

the brush border of the bronchial epithelium and also invade macrophages

Question 33

what does the A subunit of the A-B toxin produced by B. pertussis do

Answer 33

ADP-ribosylates and inactivates guanine nucleotide-binding proteins

Question 34

what is the stain and shape of pseudomonas aeruginosa

Answer 34

opportunistic aerobic gram negative bacillus

Question 35

who is pseudomonas infection particularly deadly in

Answer 35

people with cystic fibrosis, severe burns or neutropenia

Question 36

what does P. aeruginosa secrete in the lungs of people with cystic fibrosis

Answer 36

alginate, which forms a biofilm that protects bacteria from antibodies, complement, phagocytes and antibiotics

Question 37

what infection is likely if there is a gram-negative bacterial vasculitis accompanied by thrombosis and hemorrhage

Answer 37

P. aeruginosa

Question 38

how does Y. pestis ensure its owns spread

Answer 38

forming a biofilm that obstructs the gut of the infected flea

Question 39

where is the infected fleabite usually located with bubonic plague

Answer 39

in the leg, where it forms a small pustule or ulcer

Question 40

what causes chancroid

Answer 40

Haemophilus ducreyi

Question 41

describe (generally) mycobacterium

Answer 41

slender, aerobic rods that grow in straight or branching chains

Question 42

what is the critical mediator that enables macrophages to contain the M. tuberculosis infection

Answer 42

IFN-gamma

Question 43

what cells are the primary mediators of M. tuberculosis infection

Answer 43

Th1 cells

Question 44

what part of the lung does secondary pulmonary TB classically involve

Answer 44

apex of the upper lobes of one or both lungs

Question 45

what do bacteria are involved in MAC infection

Answer 45

Mycobacterium avium and Mycobacterium intracellulare

Question 46

MAC infection is uncommon except in people with what>

Answer 46

T-cell immunodeficiency due to AIDS or immunosuppression resulting from treatment for transplant rejection or autoimmune disease

Question 47

what is the hallmark of MACinfections in patients with HIV

Answer 47

abundant acid-fast bacilli within macrophages

Question 48

what is the virulence of M. leprae based on

Answer 48

components of its cell wall (it secretes NO toxins)

Question 49

what determines if the M. leprae infection with cause tuberculoid or lepromatous leprosy

Answer 49

the Th cells response

Question 50

describe the stain and shape of spirochetes

Answer 50

gram negative, slender corkscrew-shaped bacteria with axial periplasmic flagella wound around a helical protoplasm

Question 51

what bacteria causes syphilis

Answer 51

Treponema pallidum

Question 52

what finding is characteristic of all stages of syphilis

Answer 52

proliferative endarteritis affecting small vessels with a surrounding plasma cell-rich infiltrate

Question 53

how is infantile syphilis most often manifested

Answer 53

nasal discharge and congestion (snuffles) in the first few months of life

Question 54

what is the main finding with primary syphilis

Answer 54

chancre

Question 55

what is the triad often associated with late manifestations of congenital syphilis

Answer 55

interstitial keratitis, hutchinson teeth and 8th nerve deafness

Question 56

what causes lime disease

Answer 56

arthropod-borne illness caused by Borrelia burgdorferi

Question 57

what is is the arthropod used to transmit lime disease

Answer 57

ixodes deer ticks

Question 58

what bacteria causes gas gangrene

Answer 58

C. perfringens

Question 59

what does C. botulinum do

Answer 59

blocks synaptic release of ACh and causes flaccid paralysis of respiratory and skeletal muscles

Question 60

what is the most important toxin that C. perfringens produces and what does it do

Answer 60

alpha toxin: it is a phospholipase C that degrades lecithin, a major component of cell membranes, and also destroys RBCs, platelets and muscle cells, causing myonecrosis

Question 61

what is the name for the infectious body of Chlamydial trachomatis

Answer 61

elementary body: metabolically inactive, spore-like structure

Question 62

what is the metabolically active part of chlamydial trachoma's

Answer 62

reticulate body

Question 63

what is the primary infection caused by C. trachomatis characterized by

Answer 63

mucopurulent discharge containing a predominance of neutrophils

Question 64

how is epidemic typhus (caused by rickettsia) transmitted

Answer 64

from person to person via body lice

Question 65

how is scrub typhus trnasmitted

Answer 65

by chiggers

Question 66

how is rocky mountain spotted fever transmitted to humans

Answer 66

by dog ticks

Question 67

what cells do rickettsia infections primary effect

Answer 67

endothelial cells

Question 68

how does bordetella pertussis appear microscopically

Answer 68

gram-negative coccobacillus

Question 69

which staphylococcus aureus hemolytic toxin lyses RBCs

Answer 69

gamma toxin

Question 70

what is similar about whooping cough and cholera toxins

Answer 70

pertussis and cholera ADP-ribosylate G proteins to stop signal transduction

Question 71

what is similar about diphtheria and pseudomonas toxins

Answer 71

diphtheria (A-B toxin) and pseudomonas (exotoxin A) prevent protein production (ADP-ribosylate ribosomes)

Question 72

what protein does Yersinia pests express to prevent phagocytosis

Answer 72

plague uses Yops to wreck phagocytosis and cytokine production as it spreads through the lymph nodes

Question 73

what causes epidemic relapsing fever and what is it

Answer 73

caused by spirochete B. recurrent, features multi organ failure, fever, chills, recurs, with lesser severity each time or spontaneous cure

Question 74

what disease causes erythema chronic migraines

Answer 74

B. burgdorferi

Question 75

what is a classic lesion in the immunosuppressed with infection of cryptococcus neoformans

Answer 75

soap bubble lesions form in the virchow-robin spaces as gelatinous masses of fungi grow unchecked

Question 76

what fungus often causes allergies and produces aflatoxin when it grows on peanuts

Answer 76

aspergillus

Question 77

what are the invasive signs and lesion of aspergillus infection

Answer 77

primary lesions are necrotizing pneumonia with sharply delineated hemorrhagic borders; target lesions; spreads widely throughout the body

Question 78

why are many gambians immune to P. vivax infections

Answer 78

gambians tend to have no duffy blood group antigens, which are the protein that P. vivax binds to

Question 79

how can Babes be distinguished from malarial microbes

Answer 79

Babes forms maltese crosses in erythrocytes and symptoms tend to be milder

Question 80

what transmits leishmania

Answer 80

sand files

Question 81

how does hydatid disease occur

Answer 81

consumption of Echinococcus granulosus/multilocularis eggs

Question 82

what chronic problem does T. spiralis cause

Answer 82

myositis

Question 83

What parasite should be considered with biliary tract disease, cholangiocarcinoma

Answer 83

Clonorchis sinensis

Question 84

What parasite should be considered with brain cysts and seizures

Answer 84

Taenia sodium (neurocysticerosis)

Question 85

What parasite should be considered with hematuria, squamous cell bladder cancer

Answer 85

Schistosomes haematobium

Question 86

What parasite should be considered with liver (hydatid) cysts

Answer 86

Echinococcus granulosus

Question 87

What parasite should be considered with microcytic anemia

Answer 87

Ancylostoma, Necator

Question 88

What parasite should be considered with Myalgias, periorbital edema

Answer 88

Trichinella spiralis

Question 89

What parasite should be considered with perinatal pruritis

Answer 89

Enterobius

Question 90

What parasite should be considered with portal hypertension

Answer 90

Schistosomes Manson I, Schistosoma japonicum

Question 91

What parasite should be considered with vitamin B12 deficiency

Answer 91

Diphyllobothrium Latum