B. Cereus Cudmore-Lewis

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Classification

Domain: Bacteria
Phylum: Firmicutes
Class: Bacilli
Order: Bacillales
Family: Bacillaceae

Species

NCBI: Taxonomy

Bacillus cereus

B. cereus under an electron microscope(7).

Habitat Information

Soil Sample Dig Location:
Lat:30.002092
Long:-97.883009
Soil: Castephen Clay Loam/ 3-5% slopes, eroded
Description: New housing development, empty lot
Precipitation:Not within 48 hours
Temperature:70, few clouds
Depth: 1.25 inches
Visibility: 10 miles
Humidity: 59%
Wind: S 10 mph
Sea Level: 1011.8
Date & Time: September 8, 2016, 18:53

Description and Significance

Description:
Color: Yellow (mustard-like color)
Form: Circular
Margin: Entire
Consistency: Semi-mucoid
Texture: Smooth
Elevation: Raised

• A standard Gram stain was performed on the sample to observe cellular morphology.
  

Gram reaction: positive
Cellular morphology: very small, clustered rods

Antibiotics
Antimicrobial Activity: Negative
Drug Resistance: B. cereus produce large amounts of β lactamase and are resistant to penicillin, ampicillin, cephalosporins, trimethoprim(8).
Significance

B. cereus can be considered significant in food manufacturing, livestock health, human disease, and pharmaceutical manufacturing.

Genome Structure

The genome of B. cereus is very similar to the genome of B. anthracis (3). B. cereus has a single, circular chromosome that is 5,411,809 nt long (4).

S Ribosomal sequences obtained from PCR:

Gel Electrophoresis results from Microbiology class. Well 4 is B. cereus sample collected by Lewis and Cudmore.

Cell Structure, Metabolism and Life Cycle

B. cereus is a rod shaped, Gram positive bacteria. B. cereus is motile via flagella and produces endospores (6).
B. cereus is a facultative anaerobe. Some metabolic molecules B. cereus makes include NADH dehydrogenases, succinate dehydrogenase, complex III, non-proton-pumping cytochrome bd quinol oxidases, and proton-pumping oxidases such as cytochrome c oxidase and cytochrome aa3 quinol oxidase (5).

Other stain results:
Capsule stain: negative
Endospore stain: negative

Additional Test Results:
Gelatinase Test: Positive for Gelatinase production

Deoxyribonuclease Test: Positive for DNAse

Lipase Test: Negative

Starch Hydrolysis: Negative

Citrate (Enteric) Test: Positive

Urea Test:Negative

Methyl Red: Negative
Voges-Proskauer: Negative

Blood Agar:(α)alpha (partial hemolysis)

SIM Test:

• Sulfur-negative
• Indole-positive
• Motility-negative

Nitrate Test: Negative for Nitrate reduction

Phenylalanine Deaminase Test: Negative
Phenol Red Test:

• Lactose-Fermentation with acid/gas production
  
• Sucrose-fermentation with acid/gas production
  
• Glucose-Fermentation with acid/gas production
  

Casease Test: Positive for Casease

Triple Iron Sugar Agar(TSI):

• Alkaline with gas production
  

Decarboxylation Test:

• Arginine-Negative
• Lysine-Positive
• Ornithine-Negative
  

Mannitol Salt Test: Positive for Mannitol Fermentation

Bile Esculin Test: Positive for Esculin breakdown

6.5% Salt Tolerance Test: Positive for Salt toleration

MacConkey Agar Test: Negative

Eosin Methylene Blue: Negative

Hektoen Enteric Agar Test: Negative

Bacitracin Susceptibility Test:

• Bacitracin (A disk)- Suceptible
• Optochin ( P disk)-Susceptible
  

Phenylethyl Alcohol Agar (PEA):Positive

Physiology and Pathogenesis

The pathogenicity of B. cereus, whether intestinal or non-intestinal, is intimately associated with the production of tissue-destructive exoenzymes.Among these secreted toxins are four hemolysins, three distinct phospholipases, an emesis-inducing toxin, and proteases. (1)

B. cereus has been known to cause food-borne illness (most notably "fried-rice syndrome"), as well as skin infections (most commonly keratitis) in humans.
In some animals, B. cereus can be used as a probiotic.
B. cereus was found to be the most common contaminant in pharmaceutical manufacturing. (2)

References

1. Bottone, Edward J. “Bacillus Cereus, a Volatile Human Pathogen.” Clinical Microbiology Reviews 23.2 (2010): 382–398. PMC. Web. 7 Dec. 2016.

2. Sandle, Tim (28 November 2014). "The Risk of Bacillus cereus to Pharmaceutical Manufacturing". American Pharmaceutical Review (Paper). 17 (6): 56.

3. Ivanova, Natalia. "Genome sequence of Bacillus cereus and comparative analysis with Bacillus anthracis." Nature, vol. 423, 1 May 2003, pp. 87-91.

4. Rasko, D., Altherr, M., Han, C., and Ravel, J. “Genomics of the Bacillus cereus group of organisms.” FEMS Microbiology Reviews. 2005. Volume 29(2). p.303-329.

5. Duport, C., Zigha, A., Rosenfeld, E., and Schmitt, P. “Control of Enterotoxin Gene Expression in Bacillus cereus F4430/73 Involves the Redox-Sensitive ResDE Signal Transduction System.” Journal of Bacteriology. 2006. Volume 188. p. 6640–6651.

6. Senesi, S., Celandroni, F., Salvetti, S., Beecher, D., Wong, A., and Ghelardi, A. “Swarming motility in Bacillus cereus and characterization of a fliY mutant impaired in swarm cell differentiation.” Microbiology. 2002. Volume 148. p. 1785-1794.

7. http://cdn.phys.org/newman/gfx/news/hires/2013/structuralst.png

8. http://www.phac-aspc.gc.ca/lab-bio/res/psds-ftss/bacillus-cereus-eng.php

Author

Page authored by Carley Cudmore and Jennifer Lewis, students of Prof. Kristine Hollingsworth at Austin Community College.