SEMR: Gram (+) bacilli Flashcards by JHOANNA LYNN LUMBOY

-Aerobic Gram-Positive Bacilli
-Catalase Positive

-Slightly curved, gram (+) rods,
PALLISADING (PICKET fence)
-Club shape appearance
-“Chinese letter” arrangement

Corynebacterium spp.

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-AKA as Klebs-Loeffler’s bacillus
-Diphtheria Toxin

Corynebacterium diphtheriae

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Microscopy
-(pallisadesor as V and L forms)
-(Babes-Ernst granules)

Corynebacterium diphtheriae

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Aerobic Gram-Positive Bacilli
Catalase Positive

Tinsdale’s Halo: +
Urease: -
Gelatin Hydrolysis: -

C.diphtheriae

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Aerobic Gram-Positive Bacilli
Catalase Positive

Tinsdale’s Halo: +
Urease: +
Gelatin Hydrolysis: +

C.ulcerans

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Aerobic Gram-Positive Bacilli
Catalase Positive

Tinsdale’s Halo: +
Urease: +
Gelatin Hydrolysis: -

C. pseudo-tuberculosis

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Test for Toxigenicity of Corynebacterium diphtheriae

Elek Test

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Aerobic Gram-Positive Bacilli
Catalase Positive

Tinsdale’s Halo: -
Urease: -
Gelatin Hydrolysis: -

C.jeikeium

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Virulence Factor
1. Hemolysin (Listeriolysin O)
2. Protein p60

Listeria monocytogenes

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Listeria monocytogenes
Virulence Factor

A hemolytic and cytotoxictoxin that
damages the phagosomemembrane

Hemolysin (Listeriolysin O)

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Listeria monocytogenes
Virulence Factor

Induces phagocytosisthrough increased
adhesion and penetration into mammalian
cells.

Protein p60

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Clinical Infections

Pregnant Women:
Stillbirth and
Spontaneous abortion

Listeria monocytogenes

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Clinical Infections

New Born: Bacteremia and meningitis

Listeria monocytogenes

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Clinical Infections

Immunosuppressed Host: Meningitis and endocarditis

Listeria monocytogenes

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Microscopy:
Gram (+) rods or
coccobacilli in pairs
or in short chains

Cultural Characteristics:
Small, round, smooth
translucent . NARROW
zone of β-hemolysis

Listeria monocytogenes

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-Very small zone
-β Hemolysis
-37°C
-Metachromatic granules
Pleomorphic (V and L forms)
-Nonmotile
-Black colonies w/
brown halo (CTBA)
-Elek test

C. diphtheriae

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-Narrow zone
-β Hemolysis
-30°C - 35°C (0.5 °C - 45°C)
-UMBRELLA Shape
INVERTED CHRISTMAS TREE
-TUMBLING MOTILITY
-Hippurate and Bile Esculin
Hydrolysis (+)
-CAMP (+): Rectangle

L. monocytogenes

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Aerobic Gram-Positive Bacilli
Catalase Positive
(2)

C. diptheriae
L. monocytogenes

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Aerobic Gram-Positive Bacilli
Catalase Negative
(3)

Erysipelothrix rhusiopathiae

Arcanobacterium

Gardnerella vaginalis

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localized painful skin infection
(work related inoculation)

Erysipeloid

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Aerobic Gram-Positive Bacilli
Catalase Negative
Clinical Infections

Erysipeloid
Septicemia
Diffuse cutaneous infection

Erysipelothrix rhusiopathiae

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Erysipelothrix rhusiopathiae
drug of choice

Penicillin

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Microscopy
-Thin, filamentous gram
(+) rods
-Arrange singly, in short
chains or V shape
-Gram variable

Erysipelothrix rhusiopathiae

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Culture Characteristics

i. Rough colonies
*Large, rough, curled
with irregular edges

ii. Smooth colonies
*small, smooth, transparent

iii. α-hemolytic after
prolonged incubation

Erysipelothrix rhusiopathiae

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Identification -“TEST-TUBE BRUSH LIKE” pattern at 22°C in gelatin stab -Produces Hydrogen sulfide (H2S) in TSI -Non-motile, pleomorphic -Negative: Urease, V-P, Esculinhydrolysis

Erysipelothrix rhusiopathiae

Aerobic Gram-Positive Bacilli Catalase Negative Clinical Infections Clinical Infection i. Pharyngitis ii. Cervical lymphadenopathy iii. Rash and desquamation of hands and feet iv. Soft tissue and sepsis

Arcanobacterium haemolyticum

Microscopy 1. Curved, gram (+) rods with pointed ends and rudimentary branching. 2. Exhibit coccal forms after 48 hours of growth

Arcanobacterium haemolyticum

Culture Characteristics -Small colonies; may be β-hemolytic (narrow zone) -Pits Agar -Black opaque dot is observed when the colony is scraped

Arcanobacterium haemolyticum

-Lipase and Lecithinase positive (EYA) -Exhibit REVERSE CAMP REACTION due to production of phospholipase D that inhibits β-lysin. -Erythromycin is the drug of choice

Arcanobacterium haemolyticum

Arcanobacterium haemolyticum Exhibit reverse camp reaction due to production of -- that inhibits β-lysin.

phospholipase D

Arcanobacterium haemolyticum Exhibit reverse camp reaction due to production of phospholipase D that inhibits--.

β-lysin

Aerobic Gram-Positive Bacilli Catalase Negative Clinical Infections -Bacterial vaginosis -Less commonly associated in UTI

Gardnerella vaginalis

malodorous discharge and vaginal pH > 4.5) reduce Lactobacillus in vagina Polymicrobial including Mobiluncus spp, Prevotella spp

Bacterial vaginosis Gardnerella vaginalis

Aerobic Gram-Positive Bacilli Catalase Negative Microscopy 1. Pleomorphic, gram variable coccobacillus or short rod. 2. Characteristic “clue cells” in wet mount. of vaginal fluid.

Gardnerella vaginalis

Presumptive Test for Gardnerella vaginalis fishlike odor, after the addition of 1 drop of 10% KOH to the vaginal washings.

Whiff Test

drug of choice for Gardnerella vaginalis

Metronidazole

Aerobic Gram-Positive Bacilli Catalase: + Motility (25°C): - Esculin Hydrolysis: - H2S (TSI): - Hemolysis: beta Urease: -

c. diptheriae

Aerobic Gram-Positive Bacilli Catalase: + Motility (25°C): + Esculin Hydrolysis: + H2S (TSI): - Hemolysis: beta Urease: -

L. monocytogenes

Aerobic Gram-Positive Bacilli Catalase: - Motility (25°C): - Esculin Hydrolysis: - H2S (TSI): + Hemolysis: gamma, alpha Urease: -

E. rhusiopathiae

Aerobic Gram-Positive Bacilli Catalase: - Motility (25°C): - Esculin Hydrolysis: - H2S (TSI): - Hemolysis: beta Urease: -

A. haemolyticum

Aerobic Gram-Positive Bacilli Catalase: - Motility (25°C): - Esculin Hydrolysis: - H2S (TSI): - Hemolysis: gamma Urease: +

G. vaginalis

Aerobic Gram-Positive Bacilli Branching Actinomycetes present in dust or soil or plant material

Nocardia

Aerobic Gram-Positive Bacilli Branching Actinomycetes Virulence Factor -Superoxide dismutase and catalase -Nocobactin – iron chelating compound

Nocardia

Aerobic Gram-Positive Bacilli Branching Actinomycetes Clinical Infections-immunocompromised Pulmonary infections

N. asteroides

Aerobic Gram-Positive Bacilli Branching Actinomycetes Clinical Infections- Cutaneous infections

N. brasiliensis

Aerobic Gram-Positive Bacilli Branching Actinomycetes Clinical Infections-yellow-orange pus, granular (“sulfur granules”)

Actinomycoticmycetomas

Aerobic Gram-Positive Bacilli Branching Actinomycetes Other Actinomycetes Gram Stain: Moderate weaving, interwining branching

Actinomadura

Aerobic Gram-Positive Bacilli Branching Actinomycetes Other Actinomycetes Gram Stain: Extensive branching with chains & spores

Streptomyces

Aerobic Gram-Positive Bacilli Branching Actinomycetes Other Actinomycetes Gram Stain: Short Rods

Gordonia

Aerobic Gram-Positive Bacilli Branching Actinomycetes Other Actinomycetes Gram Stain: Long bacilli that fragments

Tsukamurella

Aerobic Gram-Positive Bacilli Branching Actinomycetes Other Actinomycetes Gram Stain: Diptheroid like or coccobacillary (“zigzag”)

Rhodococcus

Aerobic Gram-Positive Bacilli Spore-Forming Virulence Factors 1. Glutamic acid capsule resistant to host proteolytic enzymes 2. Exotoxins

Bacillus anthracis

Bacillus anthracis Exotoxins Binding molecule to EF/LF

Protective factor

Bacillus anthracis Exotoxins Adenylate cyclase that causes edema

Edema Factor (EF)

Bacillus anthracis Exotoxins Protease that kills host cells

Lethal factor (LF)

Aerobic Gram-Positive Bacilli Spore-Forming Clinical infections Cutaneous anthrax

Bacillus anthracis

Bacillus anthracis Clinical infections -Most common but least severe. Occurs at the site of spore penetration. -Manifested by erythematous papule to ulceration and to formation of eschar.

Cutaneous anthrax

Microscopy -Large, gram (+), square- ended, gram (+) rod, singly or in chains. -“Bamboo rod” appearance -Spores are oval, located centrally to subterminally

Bacillus anthracis

Cultural Characteristics -Nonhenmolytic, large, gray and flat with irregular margin(“MEDUSA HEAD”) -Large and MMUCOID COLONIES in bicarbonate agar. -BEATEN EGG WHITE consistency -Produces “STRING OF PEARLS” in MH Agar containing 0.05 -0.5 U/mLpenicillin

Bacillus anthracis

Aerobic Gram-Positive Bacilli Spore-Forming Has 2 clinical infection forms: 1. Diarrheal 2. Emetic

Bacillus cereus

Incubation period: 8-16 hours Predominant symptoms: Diarrhea Duration of illness: 12-24 (24)hours Food Implicated: Meat producers Stability to heat: Negative

Diarrheal Bacillus cereus

Incubation period: 1-5 hours Predominant symptoms: Vomiting Duration of illness: 6-24 (9) hours Food Implicated: Fried and Boiled Rice Stability to heat: Positive

Emetic Bacillus cereus

Aerobic Gram-Positive Bacilli Spore-Forming Lecithinase: + Motile:- Penicillin Sensitivity:+ Parasporal Crystals:-

B. anthracis

Aerobic Gram-Positive Bacilli Spore-Forming Lecithinase: + Motile:+ Penicillin Sensitivity:- Parasporal Crystals:-

B. cereus

Aerobic Gram-Positive Bacilli Spore-Forming Lecithinase: + Motile:+ Penicillin Sensitivity:- Parasporal Crystals:+

B. thuringiensis

Aerobic Gram-Positive Bacilli Spore-Forming Lecithinase: + Motile: - Penicillin Sensitivity: - Parasporal Crystals: -

B. mycoides

Aerobic Gram-Positive Bacilli Spore-Forming Hemolysis: - String of Pearls: + Gelatin Hydrolysis: - Growth in PEA: -

B. anthracis

Aerobic Gram-Positive Bacilli Spore-Forming Hemolysis: + String of Pearls: - Gelatin Hydrolysis: + Growth in PEA: +

B. cereus

SEMR: Gram (+) bacilli Flashcards

(68 cards)