SEMR: Gram (+) bacilli Flashcards
-Aerobic Gram-Positive Bacilli
-Catalase Positive
-Slightly curved, gram (+) rods,
PALLISADING (PICKET fence)
-Club shape appearance
-“Chinese letter” arrangement
Corynebacterium spp.
-AKA as Klebs-Loeffler’s bacillus
-Diphtheria Toxin
Corynebacterium diphtheriae
Microscopy
-(pallisadesor as V and L forms)
-(Babes-Ernst granules)
Corynebacterium diphtheriae
Aerobic Gram-Positive Bacilli
Catalase Positive
Tinsdale’s Halo: +
Urease: -
Gelatin Hydrolysis: -
C.diphtheriae
Aerobic Gram-Positive Bacilli
Catalase Positive
Tinsdale’s Halo: +
Urease: +
Gelatin Hydrolysis: +
C.ulcerans
Aerobic Gram-Positive Bacilli
Catalase Positive
Tinsdale’s Halo: +
Urease: +
Gelatin Hydrolysis: -
C. pseudo-tuberculosis
Test for Toxigenicity of Corynebacterium diphtheriae
Elek Test
Aerobic Gram-Positive Bacilli
Catalase Positive
Tinsdale’s Halo: -
Urease: -
Gelatin Hydrolysis: -
C.jeikeium
Virulence Factor
1. Hemolysin (Listeriolysin O)
2. Protein p60
Listeria monocytogenes
Listeria monocytogenes
Virulence Factor
A hemolytic and cytotoxictoxin that
damages the phagosomemembrane
Hemolysin (Listeriolysin O)
Listeria monocytogenes
Virulence Factor
Induces phagocytosisthrough increased
adhesion and penetration into mammalian
cells.
Protein p60
Clinical Infections
Pregnant Women:
Stillbirth and
Spontaneous abortion
Listeria monocytogenes
Clinical Infections
New Born: Bacteremia and meningitis
Listeria monocytogenes
Clinical Infections
Immunosuppressed Host: Meningitis and endocarditis
Listeria monocytogenes
Microscopy:
Gram (+) rods or
coccobacilli in pairs
or in short chains
Cultural Characteristics:
Small, round, smooth
translucent . NARROW
zone of β-hemolysis
Listeria monocytogenes
-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
-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
Aerobic Gram-Positive Bacilli
Catalase Positive
(2)
C. diptheriae
L. monocytogenes
Aerobic Gram-Positive Bacilli
Catalase Negative
(3)
Erysipelothrix rhusiopathiae
Arcanobacterium
Gardnerella vaginalis
localized painful skin infection
(work related inoculation)
Erysipeloid
Aerobic Gram-Positive Bacilli
Catalase Negative
Clinical Infections
Erysipeloid
Septicemia
Diffuse cutaneous infection
Erysipelothrix rhusiopathiae
Erysipelothrix rhusiopathiae
drug of choice
Penicillin
Microscopy
-Thin, filamentous gram
(+) rods
-Arrange singly, in short
chains or V shape
-Gram variable
Erysipelothrix rhusiopathiae
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
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