Gram Positive Bacilli Aerobes Flashcards
Spore – forming
Bacillus spp.
Clostridium spp.
Non – sporeforming
Corynebacterium spp.
Listeria spp.
Most members are saprophytic organisms prevalent in soil, water, and air and on vegetation.
Bacillus spp.
Bacillus spp. Are motile except
B. anthracis and B. mycoides
Biochemical tests of bacillus spp.
(+) catalase; ferments glucose; starch hydrolyzers
causative agent of ANTHRAX
Bacillus anthracis
a disease of wild and domestic animals including sheep, goats,
horses and cattle.
ANTHRAX
produces endospores (central/subterminal) which are highly
resistant to heat and desiccation.
Bacillus anthracis
Habitat of Bacillus anthracis
SOIL (contracted by HERBIVORES)
Mode of Transmission: Inoculated with the spores, either by traumatic introduction, ingestion or inhalation during exposure to contaminated animal products.
Bacillus anthracis
Bacillus anthracis Gram positive (+) in chains;
“bamboo – fishing rod appearance”
Capsule of Bacillus anthracis
polypeptide D-glutamic acid
Bacillus anthracis Gram positive arranged singly;
“boxcar”
Gray to white colonies, raised with curled, irregular whirling margin
Bacillus anthracis
“MEDUSA HEAD” or “ground glass colonies”
Bacillus anthracis
Used for Cultural Characteristics of Bacillus anthracis
Blood Agar
disturbed portion of colony stands up like “BEATEN EGG WHITE” when lifted up
Bacillus anthracis
Gelatin: inverted pine – tree growth
Bacillus anthraci
Reduced nitrates to nitrite
Bacillus anthracis
Pathogenicity of Bacillus anthracis
Polypeptide capsule
Anthrax toxin
B. anthracis
complex protein toxin produced in vivo responsible for the signs and symptoms of disease
Anthrax toxin
3 types of Anthrax toxin
Protective antigen (PA);
Edema factor (EF);
Lethal factor (LF)
Binds to specific cell receptors; forms a membrane channel that mediates entry of EF and LF into the cell
PROTECTIVE ANTIGEN
an adenylate cyclase; with PA, it forms a toxin known as edema toxin
EDEMA FACTOR
with PA forms lethal toxin which is major virulence factor and cause of death in infected animal.
LETHAL FACTOR
Pathology of Bacillus anthracis
CUTANEOUS ANTHRAX (Malignant Pustule)
PULMONARY ANTHRAX/WOOLSORTER’S DSS.
GASTROINTESTINAL ANTHRAX/MILZBRAND
Occurs on exposed surfaces of the arms or hands followed in frequency by the face and neck
CUTANEOUS ANTHRAX (Malignant Pustule)
A pruritic papule develops 1–7 days after entry of the organisms or spores through a scratch; it rapidly changes into a vesicle or small ring of vesicles, and necrotic ulcer develops
CUTANEOUS ANTHRAX (Malignant Pustule)
Lesions are 1 – 3 cm in diameter and have a characteristic central black eschar.
CUTANEOUS ANTHRAX (Malignant Pustule)
Lesions are 1 – 3 cm in diameter and have a characteristic central black eschar.
CUTANEOUS ANTHRAX (Malignant Pustule)
PULMONARY ANTHRAX/WOOLSORTER’S DSS.
Early manifestations: marked hemorrhagic necrosis and edema of mediastinum; substernal pain is prominent
PULMONARY ANTHRAX/WOOLSORTER’S DSS.
Hemorrhagic pleural effusion follows; cough is secondary to the effects on trachea; sepsis occur; bowel ulceration; hemorrhagic meningitis
PULMONARY ANTHRAX/WOOLSORTER’S DSS.
acquired through ingestion of spores and affects either the oropharyngeal or the abdominal area.
GASTROINTESTINAL ANTHRAX/MILZBRAND
o oropharyngealsymptomsincludesorethroat, lymphadenopathy and edema of throat and chest.
o Abdominal symptoms include abdominal pain, vomiting and bloody diarrhea are clinical signs.
GASTROINTESTINAL ANTHRAX/MILZBRAND
In gram staining B. anthracis, the bacteriologic smear could be
Exudate, pus, sputum or blood
Serological tests for Bacillus anthracis
ASCOLI test
ELISA
Microhemagglutination
Fried rice Bacillus
Bacillus cereus
a very close relative to Bacillus anthracis, found within the soil.
Bacillus cereus
spores are NOT killed by BOILING
Bacillus cereus
Habitat: vegetative cells and spores ubiquitous in nature, may transiently colonize skin or GIT or respiratory
Bacillus cereus
Small shiny, compact to large, feathery, spreading type, maybe “MEDUSA head”, frosted glass colonies
Bacillus cereus
Penicillin resistant, beta – hemolytic, MOTILE, produces a wide zone of lecithinase on egg yolk agar
Bacillus cereus
Virulence Factors of Bacillus cereus
Enterotoxins (ST and LT)
Cerelysin
Phospolipase C
Pyogenic Toxin
common LABORATORY CONTAMINANTS
Bacillus subtilis
Hay fever
Bacillus subtilis
used for antibiotic production
Bacillus subtilis
Treatment of infection with Bacillus subtilis
β – lactam antibiotics
Diagnostic tests for B. subtilis
i. Ascoli Test (Precipitin Test)
ii. Catalase Test
iii. Direct Fluorescent Antibody Test
differentiates Bacillus from Clostridium
Catalase test
Corynebacterium diphtheriae Group
C. diphtheriae
C. ulcerans
C. pseudotuberculosis
clubbed or irregularly shaped
Corynebacterium spp.
“coryneform or diphtheroid “ bacteria
Corynebacterium spp.
“Kleb-loeffler’s bacillus”
Corynebacterium diphtheriae
Habitat: human nasopharynx but only in carrier state
Corynebacterium diphtheriae
pleomorphic, club-shaped “picket-fence” or “Chinese characters”
Corynebacterium diphtheriae
Corynebacterium diphtheriae
CULTURE and ISOLATION:
Gray black after 48 hrs.
May be both large and small and flat or convex
Cystine–Tellurite agar
Corynebacterium diphtheriae
CULTURE and ISOLATION:
Dark brown to black with brown to black halos
Tinsdale’s agar
Corynebacterium diphtheriae
CULTURE and ISOLATION:
Pleomorphic appearance, arranged side by side
Display metachromatic granules – “ Babes-Ernst granules”
Loeffler agar
Corynebacterium diphtheriae virulence factor:
DIPTHERIA TOXIN
Corynebacterium diphtheriae virulence factor:
DIPTHERIA TOXIN
a potent exotoxin that destroys host cells by inhibiting protein synthesis
DIPTHERIA TOXIN
Pathology/Spectrum of Dss of Corynebacterium diphtheriae
RESPIRATORY DIPTHERIA
CUTANEOUS DIPHTHERIA
a pharyngitis characterized by the development of an exudative membrane that covers the tonsils and pharyngeal wall.
RESPIRATORY DIPTHERIA
• Barcoo rot
• Slow healing ulcers and membrane formation
• Complication is less common
CUTANEOUS DIPHTHERIA
an animal pathogen causing mastitis in domestic animals
Corynebacterium ulcerans
MOT: contact with animals and/or ingestion of unpasteurized dairy products
Corynebacterium ulcerans
MOT: contact with animals and/or ingestion of unpasteurized dairy products
Corynebacterium ulcerans
an animal pathogen causing granulomatous lymphadenitis in humans
Corynebacterium pseudotuberculosis
Virulence factor of Corynebacterium pseudotuberculosis
dermonecrotic toxin; can also produce diphtheria toxin
MOT of Corynebacterium pseudotuberculosis
contact with animals
Motile with the characteristic of tumbling motility
Listeria monocytogenes
Gram positive coccobacilli, in singly or short chains resembling streptococci
Listeria monocytogenes
Culture: small, smooth, translucent grayish blue colonies surrounded by a narrow zone of beta hemolysis
Listeria monocytogenes
SIM: umbrella-shaped / inverted Christmas tree at 25°C but not at 35°C
Listeria monocytogenes
VF of Listeria monocytogenes
Flagella
Endotoxin –Listeriolysin O (hemolytic & cytotoxic)
Pathology of Listeria monocytogenes
- Granulomatosisinfantiseptica
- Neonatalmeningitis
- Septicemia
Specimens for diagnosis of listeriosis
blood, swabs of lesions and CSF
Specimens for diagnosis of listeriosis
blood, swabs of lesions and CSF
“red disease”
Erysipelothrix rhusiopathiae
“red disease”
Erysipelothrix rhusiopathiae
Only species in the genus that cause human disease; not part of the human flora
Only species in the genus that cause human disease; not part of the human flora
Erysipelothrix rhusiopathiae
Gelatin stab culture – “pipe cleaner” or “test tube brush” pattern at 22 deg. Celsius
Erysipelothrix rhusiopathiae
localized skin infection that resembles streptococcal erysipelas; self- limiting
Erysipeloid
