B. Cereus Cudmore-Lewis

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Classification

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

Species

NCBI: Taxonomy

Bacillus cereus

Sembcereus.png
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

Soil dig.jpg

Description and Significance

Streak plate.jpg

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: Genes.jpg


GelE.jpeg
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
Gels.jpg
Deoxyribonuclease Test: Positive for DNAse
Dnase.jpg
Lipase Test: Negative
Lipase.jpg
Starch Hydrolysis: Negative
Starch.jpg
Citrate (Enteric) Test: Positive
Citrate.jpg
Urea Test:Negative
Urea.jpg
Methyl Red: Negative
Voges-Proskauer: Negative
Mrvp.jpg
Blood Agar:(α)alpha (partial hemolysis)
Ba.jpg
SIM Test:

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

Sim.jpg
Nitrate Test: Negative for Nitrate reduction
Nitrate.jpg
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

Decarb.jpg
Casease Test: Positive for Casease
Milk.jpg
Triple Iron Sugar Agar(TSI):

  • Alkaline with gas production

Tsi.jpg
Decarboxylation Test:

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

Dcjpg.jpg
Mannitol Salt Test: Positive for Mannitol Fermentation
Msa.jpg
Bile Esculin Test: Positive for Esculin breakdown
Bile.jpg
6.5% Salt Tolerance Test: Positive for Salt toleration
Saltbc.jpg
MacConkey Agar Test: Negative
Macjpg.jpg
Eosin Methylene Blue: Negative
Emb.jpg
Hektoen Enteric Agar Test: Negative
He.jpg
Bacitracin Susceptibility Test:

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

Ap1.jpg
Ap2.jpg
Phenylethyl Alcohol Agar (PEA):Positive
Pea.jpg

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.