Gram- Positive Bacilli

Question 1

It is both a human and animal pathogen
It is aerobic or facultatively anaerobic and non-spore formin

Answer 1

Listeria monocytogenes

Question 2

It is motile with pretrichous flagella and exhibits a characteristic ―tumbling motility

Answer 2

Listeria monocytogenes

Question 3

It can grow in a high salt medium with up to 10% NaCl

Answer 3

Listeria monocytogenes

Question 4

 It is recovered from the soil, dust, water, dairy products, and processed meats
 It causes miscarriage or stillbirth in humans

Answer 4

Listeria monocytogenes

Question 5

Virulence factors of Listeria monocytogenes

Answer 5

Listeriolysin O, catalase, supeoxide dismutase, phospholipase C, and p60

Question 6

Mode of acquisition of Listeria monocytogenes

Answer 6

Ingestion of contaminated food such as meat, chicken, dairy products, and
vegetables

Question 7

Microscopy: Coccobacillary in form and are arranged singly or in short chains that resemble
streptococci

Answer 7

Listeria monocytogenes

Question 8

Culture: BAP-colonies are small, smooth, transluscent, grayish blue, and are surrounded by a
narrow zone of Beta hemolysis

Answer 8

Listeria monocytogenes

Question 9

It is a serious infection that affects neonates, pregnant women, and immunocompromised hosts
 Processed meat products should be thoroughly cooked or heated before consumption as a
primary preventive measure

Answer 9

Listeriosis

Question 10

are the most important host defense against Listeriosis

Answer 10

Macrophages and T-lymphocytes

Question 11

It usually occurs during the third trimester of pregnancy
 It leads to miscarriage or stillbirth
 Signs and symptom: Flu-like illness, fever, headache, and myalgia

Answer 11

Maternal disease (Pregnancy)

Question 12

It is associated with an intrauterine infection due to the aspiration of infected amniotic
fluid
 The infected infants are at full term and appear healthy at birth
 It leads to meningitis that is usually seen by the third week of life

Answer 12

Neonatal disease

Question 13

It develops though the ingestion of contaminated dairy products and processed meat
products

Answer 13

. Disease of immunocompromised host

Question 14

SIM test: Has an ―”umbrella-shaped” or inverted Christmas tree‖ pattern at room
temperature at 25C but not at 35C

Answer 14

Listeria monocytogenes

Question 15

Biochemical test for Listeria monocytogenes

Answer 15

(+) Glucose fermentation
(+) Catalase and motility
(+) CAMP reaction-―block type‖ hemolysis
(+) Hippurate and bile esculin hydrolysis
(+) growth in 6.5% NaCl
(+) Voges-Proskauer and Methyl red tests
(-) H2S production, nitrate reduction, and urease

Question 16

Gram positive bacilli, the only catalase-negative, non-spore-forming, Gram-positive, rod-shaped bacterium that
produces hydrogen sulfide.

Answer 16

Erysipelothrix rhusiopathiae

Question 17

It is isolated from wild and domestic animals like birds and fish

Answer 17

Erysipelothrix rhusiopathiae

Question 18

Major: reservoir of Erysipelothrix rhusiopathiae

Answer 18

Domestic swine

Question 19

Gelatin stab culture: Has a pattern of a ―”pipe cleaner” or a ―”test tube brush” at 22C

Answer 19

Erysipelothrix rhusiopathiae

Question 20

Mode of transmission: Direct contact with infected excreta, blood, and flesh of animals through
skin breaks

Answer 20

Erysipelothrix rhusiopathiae

Question 21

Predisposed individuals: Veterinarians and fish handlers

Answer 21

Erysipelothrix rhusiopathiae

Question 22

Culture: BAP- Colonies are pinpoint with alpha-hemolytic zone

Answer 22

Erysipelothrix rhusiopathiae

Question 23

Best specimens for Erysipelothrix rhusiopathiae

Answer 23

Tissue biopsies or aspirates from skin lesion

Question 24

the best site for collecting specimens of Erysipelothrix rhusiopathiae

Answer 24

the outward margin of the lesion

Question 25

a. Large and rough colonies-curled, slender, filamentous with a tendency to overdecolorize and become Gram-negative bacilli  b. Small and smooth colonies-transparent, glistening, and slender rods

Answer 25

E.rhusio

Question 26

Culture: BAP- Colonies are pinpoint with alpha-hemolytic zone The organism can grow on BAP and CAP for up to seven days

Answer 26

Erysipelothrix rhusiopathiae

Question 27

curled, slender, filamentous with a tendency to overdecolorize and become Gram-negative bacilli

Answer 27

Large and rough colonies

Question 28

transparent, glistening, and slender rods

Answer 28

b. Small and smooth colonies-

Question 29

(+) H2S production in a TSI medium (+) Glucose and lactose fermentation (-) Catalase, oxidase, esculin hydrolysis, nitrate reduction, VP, and urease

Answer 29

Erysipelothrix rhusiopathiae

Question 30

The species of this genus are classified Gram-positive rods as pleomorphic, non-motile, rod-shaped,

Answer 30

Arcanobacterium

Question 31

Biochemical test: (-) catalase

Answer 31

Arcanobacterium

Question 32

is both lipase-and lecithinase-positive and has a positive reverse CAMP reaction due to phospholipase D

Answer 32

Arcanobacterium haemolyticum

Question 33

Significant species of Arconbacterium

Answer 33

A. haemolyticum, A. pyoges, and A. bernardiae

Question 34

Culture: BAP-Colonies have a narrow zone of Beta hemolysis; exhibit pitting of the agar with a black opaque dot

Answer 34

Arcanobacterium

Question 35

 They can cause pharyngitis and endocarditis

Answer 35

arcanobacterium

Question 36

 Culture: BAP-Colonies have a narrow zone of Beta hemolysis; exhibit pitting of the agar with a black opaque dot

Answer 36

Acranobacterium

Question 37

is both lipase-and lecithinase-positive and has a positive reverse CAMP reaction due to phospholipase D

Answer 37

A. haemolyticum

Question 38

The members of this genus are obligately aerobic Gram-positive rods that are motile by peritrichous flagella

Answer 38

Kurthia

Question 39

BAP-Colonies exhibit a large ―"medusa-head" appearance Nutrient agar- Colonies exhibit a rhizoid growth

Answer 39

Kurthia

Question 40

Biochemical test: (+) Catalase; (-) gelatinase and oxidase

Answer 40

Kurthia

Question 41

The mebers of this large and diverse group are composed of Gram-positive bacilli

Answer 41

Aerobic Actinomycetes

Question 42

The members are classified as aerobes with a branching filamentous growth that extends along the agar due to the substrate hyphae, and into the agar due to the aerial hyphae

Answer 42

Aerobic Actinomycetes

Question 43

Microscopy: Filamentous Gram-positive rods with a "beaded appearance"

Answer 43

Aerobic Actinomycetes

Question 44

 Culture: Cells elongate to form branching, filamentous forms while some organisms form hyphae on the agar surface or into the agar.

Answer 44

Aerobic Actinomycetes

Question 45

Aerobic actinomycetes with a branching filamentous growth along the agar due to the?? and into the agar due to the?

Answer 45

Substrate hyphae; aerial hyphae

Question 46

o Wet mount/hanging drop method: Exhibits a "tumbling motility‖ at room temperature

Answer 46

L.mono

Question 47

SIM test: Has an ―umbrella-shaped‖ or inverted Christmas tree‖ pattern at room temperature at 25C but not at 35C

Answer 47

L.mono

Question 48

o Growth occurs at a wide temperature range of 0.5C to 45C o It requires a slightly increased amount of CO2

Answer 48

L.mono

Question 49

Their cell wall contains peptidoglycan, meso-diaminopimelic acid (DAP), and the sugars, arabinose and galactose

Answer 49

Nocardia

Question 50

The species grow on media that are used to recover fungi

Answer 50

Nocardia

Question 51

Culture: Colonies exhibit wrinkled, chalk-like, and orange-tan pigmentation.

Answer 51

Nocardia

Question 52

o It is a chronic, localized, painless subcutaneous infection that is characterized by the presence of sulfur granules in the affected tissue

Answer 52

Actinomycetoma (Actinomycotic mycetoma)

Question 52

Differential test: Resistant to lysozyme

Answer 52

Nocardia

Question 53

o It is a confluent bronchopneumonia where the sputum is thick and purulent, although the encapsulation of the abscess is absent o The affected tissues do not have sulfur granules

Answer 53

2. Pulmonary disease Causative agent: N. cyriacigeorgica and N. farcinic

Question 54

what agar is used to observe the morphology of actinomyctes, and to differentiate branching Nocardia species from non-branching Rhodococcus species

Answer 54

Tap water agar

Question 55

Incubation at ___ promotes the growth of Nocardia species

Answer 55

Incubation at 10% CO2

Question 56

It is non-motile and partially acid-fast, and is composed of mycolic acid with longer carbon chains

Answer 56

Rhodococcus equi

Question 57

it can persist and replicate within macrophages

Answer 57

Rhodococcus equi

Question 58

Microscopy: Coccobacilli with a ―zigzag‖ pattern and a filamentous form  Culture: BAP-Colonies exhibit a pale pink or yeloow color

Answer 58

Rhodococcus equi

Question 58

It can infect immunocompromised individuals (HIV patients) and cause slowly progressive, granulomatous pneumonia

Answer 58

Rhodococcus equi

Question 59

The species of this genus vary from Gram-positive to Gram-variable rods

Answer 59

Gordonia

Question 59

Culture: Colonies are smooth and slimy with irregular edges; but may appear as dry or rough; and exhibit the presence of mycelia

Answer 59

Gordonia

Question 59

Differential test: Susceptible to lysozyme

Answer 59

Rhodococcus equi

Question 60

The members are slightly acid-fast when the kinyoun method is used

Answer 60

Tsukamurella

Question 61

Culture: Colonies are circular with rhizoid edges; has no aerial hyphae; and exhibit white or orange pigmentatio

Answer 61

Tsukamurella

Question 62

Culture: Colonies are dry to chalky and heaped; some colonies exhibit a grayish white color and a ―musty basement odor‖

Answer 62

Streptomyces

Question 63

 The microscopic and colony morphology of the species of this genus is very similar to that of the Nocardia species

Answer 63

Actinomadura

Question 64

 It causes fungal wound infection that is known as eumycetoma

Answer 64

Actinomadura

Question 65

The most common form of eumyctetoma is known as mycetoma pedis in which the infection is localized on the patient‘s foot

Answer 65

Actinomadura

Question 66

Culture: Routine agar-Colonies exhibit a ―molar tooth‖ appearance

Answer 66

Actinomadura

Question 67

t is the etiologic agent of Whipple‘s disease that affects the gastrointestinal tract joints, and muscles and is characterized by abdominal pain and diarrhea

Answer 67

Tropheryma whipplei

Question 68

It is a gram-positive actinomycete and a facultative, intracellular pathogen

Answer 68

Tropheryma whipplei

Question 68

 It is isolated from human feces, saliva, and gastric secretions  Diagnostic test: (+) periodic acid Schiff staining (PAS) macrophages

Answer 68

Tropheryma whipplei