Jordan.Arredondo
Classification
Domain: Bacteria
Kingdom: Eubacteria
Phylum: Firmicutes
Class: Bacilli
Order: Bacillales
Family: Bacillaceae
Genus: Bacliiius
NCBI link to find]
Species
NCBI: Taxonomy |
Genus species: Bacillus Cereus
Habitat Information
Describe the location and conditions under which the organism was isolated.
After taking my original soil sample from the loading docks area on Town Lake, off of the shores of the Colorado River and yielding no substantial growth on the agar plate containing 12 samples, I began to work with another student's gram positive sample on 2/27/15.
Basically this aerobic bacteria is found all around the world, near vegetative growth.
This Bacteria has optimum growth conditions and they are as follows:
1.) 28 - 35 degress celsius
2.) Oxygen
3.) Sediment
4.) Food products act as a host
Description and Significance
Describe the appearance (colonial and cellular), possible antimicrobial activity etc. of the organism, and why the organism might be significant.
This organism is a large, rod-shaped, endospore forming gram positive bacteria. Bacillus Cereus is said to be most closely related to Bacillus Anthracis, which causes Anthrax!!! and also related to Bacillus thuringiensis, which is found in some insect pesticides.
Without stating where, the bacteria was first isolated in 1969 from a man with a fatal case of pneumonia, samples taken from his blood and lung fluid.
https://microbewiki.kenyon.edu/index.php/Bacillus_cereus
http://textbookofbacteriology.net/B.cereus.html
Genome Structure
Describe the size and content of the genome.
How many chromosomes? 5481 genes
Circular or linear? Circular
Other interesting features? A cluster within the genome encodes for an arginine deiminiase metabolic pathway that is said to have a role in it's survival with the resistance from acidic type conditions. The arginine deiminase produces ammonia and that is what protects the cells from high acidic environments until the levels rose to level out.
What is known about its sequence?
Include S Ribosomal sequence that you obtained from PCR and sequencing here.
https://microbewiki.kenyon.edu/index.php/Bacillus_cereus
http://www.ncbi.nlm.nih.gov/pubmed/2843090
Cell Structure, Metabolism and Life Cycle
Interesting features of cell structure;
To maintain the cell's shape, a thick peptidoglycan makes up the inner membrane. This organism is motile, using a flagella for swimming and swarming. In a single cell it uses a swimming motion with a shorter flagellated rods and when the organism uses a swarming function, the flagellum has been seen to be 3 to 4 times longer.
how it gains energy; This is a facultative aerobe that can use oxygen as a terminal electron acceptor, and uses methods of anaerobic respiration for energy as well. In aerobic respiration, the organism reduces equivalents produced from glycolysis and the Kreb's cycle, reoxidizing them by the electron transport chain. In anaerobic respiration, the organism uses fermentation to make energy.
what important molecules it produces.
https://microbewiki.kenyon.edu/index.php/Bacillus_cereus
Physiology and Pathogenesis
Biochemical characteristics,
enzymes made,
other characteristics that may be used to identify the organism;
contributions to environment (if any).
Not all strains produce toxins, in fact some are used as an antifungal compound and have been useful for farming, suppressing fungi in crop disease.
If relevant, how does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
SInce 1955, B. cereus has been recognized as a cause of food poisoning in humans, but has never really become noticeable in food poisoning cases overall. It is stated that in 2003 only two food borne diseases were reported to the CDC positive for B. cereus. As a food borne illness some of the symptoms are caused, consist of abdominal cramps, diarrhea and has an incubation time of 8-16 hours, that is considered the long incubation forming versus the short incubation forming which has an incubation period of 8 hours with symptoms of abdominal cramps, nausea and vomiting. An illness in both short and long incubation is said to last about 24 hours.
B. cereus produces one emetic toxin and three different enterotoxins. The third enterotoxin (EntK) which is a single component protein is stated as the one that's involved in food poisoning. Holes are made in the membranes of the affected cells by all three of the cytotoxic enterotoxins. One of the three enterotoxins, non-hemolytic enterotoxin (Nhe) is the one responsible for causing diarrhea in food poisoning cases.
A few of the virulence factors include: HBL that can result in blindness and detachment of the retina, gangrene, cellulitis, and septic meningitis and endocarditis.
From a blood culture study in 1988, by Weber et al. showed the following about susceptibility and resistance during microdilution:
All strains showed susceptible to imipenem, vancomycin, chloramphenicol, gentamicin and ciprofloxacin (shown to be highly effective in B. cereus wound infections) Many strains were susceptible to erythromycin and tetracycline Most strains were resistant to clindamycin, cefazolin, and cefotaxime
All B. cereus isolates were also shown to be resistant to penicillin, oxacillin and cephalosporins, but no to mezlocillin.
https://microbewiki.kenyon.edu/index.php/Bacillus_cereus
http://textbookofbacteriology.net/B.cereus.html
References
Author
Page authored by Jordan Arredondo, student of Prof. Kristine Hollingsworth at Austin Community College.