Micro - General lecture 1,2

Question 1

Folliculitis causative agent

Answer 1

Staph aureeus

Question 2

Staphylococcus aureus lab tests

Answer 2

Gram + Cocci in grape like clusters
Catalase +
Coagulase +
Beta hemolytic

Question 3

S. aureus protein A

Answer 3

Inhibits complement activation by binding to Fc portion of IgG

Question 4

Honey Crusted lesions - starting around the mouth and nose

Patches of itchy, oozing vesicles

Answer 4

Impetigo - Staph aureus (also Strep pyogenes)

Question 5

Large blisters over entire body - filled with clear fluid and no bacteria. Entire skin peels within 2 days - grows back in 7-10 days.

Answer 5

Staphylococcal Scaled Skin Syndrome/Ritter’s Disease - caused by S. aureus exfoliative toxin

Question 6

Localized form of Staphylococcal Scalded Skin Syndrome

Answer 6

Bullous Impetigo

Question 7

Fever, hypotension, diffuse, macular erythematous rash (Desquamation of the skin, including palms and soles).
Shock, multiple organ failure, death

Answer 7

Toxic Shock Syndrome - TSST1-superantigen of S. aureus

Question 8

Streptococcus pyogenes lab tests

Answer 8

Group A Beta hemolytic strep growing in chians

Question 9

Warm, erythematous, swollen lesions.
Acute spreading infection of subcutaneous tissue developing within a few hours-days.
Predisposed to trauma or skin lesion

Answer 9

Cellulitis
Strep pyogenes
also S aureus and anaerobes

Question 10

Intense pain at site of infection - pain is disproportionate to appearance of infected area.
Rapidly progressive disease which destroys muscle, fat, and skin tissue

Answer 10

Necrotizing fasciitis - “Flesh eating disease”

Strep pyogenes

Question 11

Different types of Necrotizing fasciitis

Answer 11

Type 1: Polymicrobial (at least 1 anaerobe with at least 2 faculatative bacteria)
Type 2: Strep pyogenes with or without S. auresus
Type 3: Gas gangrene: Clostridium perfringens

Question 12

Sandpaper rash on trunk and inner arms and legs.

Desquamation occurs in about 5-7 days. Strawberry tounge

Answer 12

Scarlet fever.

Complication of strep throat - production of pyrogenic exotoxins (Strep pyogenes)

Question 13

Bright red rash with RAISED boarders - butterfly pattern on face.

Answer 13

Erysipelas - infection spreads from skin to lymph nodes

Question 14

Causative agent of Acne

Answer 14

Propionibacterium acnes

Question 15

Propionibacterium acnes lab tests

Answer 15

Gram + rods

Metabolize sebum - produce propionic acid

Question 16

Causative agent of Leprosy/Hansen’s disease

Answer 16

Mycobacterium leprae

Question 17

Mycobacterium leprae lab tests

Answer 17

Acid-fast rod that does NOT gram stain well because of waxy, thick, mycolic acid (intracellular)

Question 18

2 types (and etiology) of leprosy

Answer 18

Tuberculoid leprosy: Good CMI, less severe infection

Lepromatous leprosy: Poor CMI - severe infection

Question 19

Dry, blotch, red lesions on the face and trunk and extremities.
Nerve damage results in LOSS OF FEELING (prone to trauma)

Answer 19

Tuberculoid leprosy

Question 20

Skin thickening and nodules
large # of bacteria
Thickening of nostrils, ears, and cheeks - eventually destroy septum of nose
“Leonine facial appearance”

Answer 20

Lepromatous leprosy

Question 21

Pseudomonas aeruginosa lab tests

Answer 21

Gram negative rod

Blue-green pigment - grape like smell

Question 22

Hot tub folliculitis (also swimming pool)

Answer 22

Pseudomonas aeruginosa

Question 23

Ecthyma gangrenosum

Answer 23

Characteristic lesion of bacteremia of Pseudomonas aeruginosa

Question 24

Gram + rod with endospores and a glutamic acid capsule
Train/box car arrangement
7-10 days later - develop painless BLACK ESCHAR

Answer 24

Bacillus anthracis - cutaneous anthrax

Wool sorters, cattle ranchers

Question 25

Differentiate between meningitides and gonorrhoeae

Answer 25

Meningitidis metabolizes maltose | Gonorrhoeae metabolizes glucose AND maltose

Question 26

Neisseria meningitdis lab tests

Answer 26

``` Gram negative diplococcic Culture on THAYER-MARTIN agar non-motile, fastidious Capnophilic; 5% CO2 LOS: Lipooligosaccharide (No O antigen) ```

Question 27

N. meningitides major virulence factor for Meningococcemia

Answer 27

Capsule - antiphagocytic

Question 28

Fever, Arthralgia, Muscle pain, PETECHIAL rash | Growth on Thayer-martin agar

Answer 28

Meningococcemia - Neiseria

Question 29

Complication of Meningocooccemia

Answer 29

Waterhouse-Friderichsen Syndrome: Bilateral hemorrhage of adrenal galndes Coma Death can occur in 6-8 hours

Question 30

Menomune

Answer 30

Meningococcemia vaccine - Meningococcal capsular polysaccharide vaccine Does NOT work in children < 2 years old

Question 31

Menactra

Answer 31

Meningococcal conjugate vaccine recommended for college students, army recruits, splenectomy, and travelers

Question 32

Causative Agent o Syphilis

Answer 32

Treponema pallidum

Question 33

Treponema pallidum lab tests

Answer 33

Spirochete - usually NOT visible on gram stain

Question 34

Primary phase of Syphilis

Answer 34

Painless chancre (raised, red lesion) at site of infection

Question 35

Secondary phase of Syphilis

Answer 35

Flu like symptoms Disseminated disease: COPPER COLORED rash over entire body and on PALMS and SOLES of the feet Condyloma latum: Soft fleshy papules in genital region

Question 36

Late phase of Syphilis

Answer 36

Cardiovascular Neurosyphilis Benign tertiary: Gummas

Question 37

Gram negative aerobic rod that is an obligate intracellular bacteria. Lyses the phagosome before lysosome-phagosome fusion. Causes disease spread by the American dog tick.

Answer 37

Rickettsia rickettsii - Rocky Mountain spotted Fever

Question 38

A seasonal disease. Non-itchy rash that begins on the hands and feet and spreads inwards to trunk (centripetal spread). Initial maculopapular rash but later stages becomes petechial and hemorrhagic

Answer 38

Rocky Mountain spotted Fever - Rickettsia rickettsii

Question 39

Centrifugal (trunk to extremities) spread of a maculopapular rash 2-3 days after onset of fever, chills, headache, myalgia, lymphadenopathy

Answer 39

Scrub Typhus - Orientia tsutsugamushi | NOT a tick - think traveler - transmitted by chiggers - mite larvae

Question 40

Clostridium perfringens lab tests

Answer 40

Gram + spore forming rods Strict anaerobe. Spores. alpha toxin, lecithinase: Breaks down lipids in cell membranes resulting in cell death "Drum stick" Or "Tennis racket" appearance

Question 41

Severe pain that is disproportionate to physical findings. Swelling with hemorrhagic bullae Crepitation May have brownish foul smelling discharge

Answer 41

Gas gangrene - C. perfringens

Question 42

Cause of an erysipeloid infection

Answer 42

Erysipelothrix rhusipathiae | Gram + rod in GI tract of animals

Question 43

Lab tests for Vibrio vulnificus

Answer 43

Gram negative, comma shaped | Halophile: wound exposed to salt water

Question 44

Causative agent of Cat scratch fever

Answer 44

Bartonella henselae | Gram negative, aerobic bacillus

Question 45

In AIDS patients - cutaneous papules/nodules that resembles Kaposi sarcoma. Patient has cats.

Answer 45

Bacillary Angiomatosis - B. henselae

Question 46

Animal bites:

Answer 46

Pasteurella multocida Gram negative coccobacillus, oxidase - positive Bipolar staining "Saftey pin"