Gram Postive Bacilli Flashcards
Classification of bacillus based on the location and shape of the spore: Ellipsoidal and does not cause swelling.
Group 1.
General Characteristics: Sporeformer (central spore) Strictly aerobic/Facultative Anaerobe Catalase positive M except B.anthracis; Thermophilic
Bacillus
Classification of bacillus based on the location and shape of the spore:has large cell more than 0.9 um.
Subgroup 1: B.anthracis, B.cerues, B.megaterium, B.thuringiensis
Classification of bacillus based on the location and shape of the spore: has small cell less than 0.9 um.
Subgroup 2: B.subtilis, B.coagulans, B.pumilus
Classification of bacillus based on the location and shape of the spores: oval shaped and are swollen.
Group 2: B.stearothermophilus, B.polymxa, B.circulans
Classification of bacillus based on the location and shape of the spore: circular shape and are swollen. Most fastidious and has complex nutrition.
Group 3: B.sphaericus, B.panthothenicus.
On 5% sheep’s blood agar, B.cereus are:
Alpha or beta hemolytic with lavander color.
Other Bacillus sp. appear as:
Large, flat and dull with a ground glass appearance.
Bacillus infection: involves the eye (Keratitis, conjunctivitis, orbital abscess)
Local Infection
Bacillus infection: infection with other organisms (wound, burnt)
Mixed infection
Bacillus infection: organism cultured from blood and CSF (meninggitis, bacteremia)
Disseminated infection
Common name of Bacillus anthracis
Anthrax Bacillus
Most virulent human pathogen in this genus. Large, NM, encapsulated, gm. (+) with square ends forming long chains. With oval, central or sub terminal spore not swollen. Disjointed bamboo fishing rod appearance.
Bacillus anthracis
Cultural characteristics of B.anthracis on BAP:
Non-hemolytic; with comma shaped growths described as Medusa head colony or lion head or cut-glass appearance or comet tail.
Cultural characteristics of B.anthracis on med. containing small amount of penicillin:
Organism can still grow but will produce similar string of pearl.
Cultural characteristics of B.anthracis on gelatin medium:
Inverted Fir Tree or Inverted Chrismtas Tree; produce acid from glucose, maltose and sucrose
Diseases of Bacillus anthracis:
Anthrax, Silberian Fever, Black Bair
Cutaneous anthrax or malignant pustule; skin contract
External
Internal: transmitted by inhalation of spore while handling wool; woolsorter’s disease or ragpicker’s disease.
Pulmonary
Internal: ingestion of improperly cooked infected meat.
Intestinal anthracis or violent enteritis
Laboratory DX of Bacillus anthracis: stained smears:
Macfadyeau’s method
Laboratory DX of Bacillus anthracis: culture m;
PLET Medium ( Polymixin, Lysozyme, Disodium EDTA, Thallou acetate)
Laboratory DX of Bacillus anthracis: the extracts if infected tissue show a ring of ppt when layered over immuned serum. Diagnosis precipitin test for B.anthracis.
Ascoli Test
Common name of Bacillus cereus.
Fried rice bacillus.
2nd most virulent human pathogen. They are called anthrax-like or pseudoanthrax bacilli; NE, M, beta-hemolytic. Most resistant species.
Bacillus cereus
Appear as rough, dry and cremated with distinct bright blue color.
PEEMBA Medium (Polymixin pyruvate-egg-yolk-mannitol-brom Thymol blue agar)
Differentiation test between B.anthracis and other Bacillus sp.
Lectin Agglutination Assays
Specimen used in B.cereus:
Blood, swab with pus, sputum, feces
Bacillus subtilis is also know as
Hay bacillus or grass bacillus
Gm +, catalase positive, bacterium commonly found in soil, obligate aerobe, rod shaped and has the ability to form a tough, protective endospore, allowing the organism to tolerate extreme environmental conditions. Common lab contaminant.
Bacillus subtilis
An intesticide
Bacillus thurgiensis
Strictly anaerobe/some are aerotolerant; catalase negative.
Clostridium
All are motile (Peri) except:
C. Perfringens, C.ramosum, C.inocuum
All have swollen spores except:
C.perfringens, C.bifermentans
All are non-encapsulated except:
C.perfringens
All are lactose + except:
C.perfringens and C.septicum
All are sucrose + except:
C.perfringens
All are single hemolytic except:
C.perfringens (double hemolysis)