00:00 / 00:00
Bacterial structure and functions
Bacillus anthracis (Anthrax)
Bacillus cereus (Food poisoning)
Corynebacterium diphtheriae (Diphtheria)
Clostridium botulinum (Botulism)
Clostridium difficile (Pseudomembranous colitis)
Clostridium tetani (Tetanus)
Streptococcus agalactiae (Group B Strep)
Streptococcus pyogenes (Group A Strep)
Bartonella henselae (Cat-scratch disease and Bacillary angiomatosis)
Legionella pneumophila (Legionnaires disease and Pontiac fever)
Salmonella typhi (typhoid fever)
Yersinia pestis (Plague)
Vibrio cholerae (Cholera)
Bordetella pertussis (Whooping cough)
Francisella tularensis (Tularemia)
Haemophilus ducreyi (Chancroid)
Mycobacterium tuberculosis (Tuberculosis)
Mycobacterium avium complex (NORD)
Gardnerella vaginalis (Bacterial vaginosis)
Coxiella burnetii (Q fever)
Ehrlichia and Anaplasma
Rickettsia rickettsii (Rocky Mountain spotted fever) and other Rickettsia species
Borrelia burgdorferi (Lyme disease)
Borrelia species (Relapsing fever)
Treponema pallidum (Syphilis)
0 / 14 complete
0 / 2 complete
Bacillus Cereus Characteristics
Bacillus Cereus Disease
Bacillus anthracis and Bacillus cereus
food poisoning p. 175, 727
spore formation p. 129
Bacillus cereus p. , 136
With Bacillus Cereus or just B. Cereus, “bacillus” means little rod, and “cereus” means wax.
So Bacillus Cereus refers to a rod-shaped bacteria that looks like a wax-candle.
Most often, this bacteria causes food poisoning, but it can also cause more serious infections, mainly in immunocompromised individuals.
B. cereus has a thick peptidoglycan cell wall, which takes in purple dye when Gram stained - so this is a gram-positive bacteria.
Also, it is a motile bacteria, as it has thread-like flagella that can help it swim in a liquid media, or swarm on a solid surface such as culture media.
It’s also aerobic, meaning it requires oxygen for growth.
B. cereus is catalase positive, meaning it produces catalase enzyme.
This can be tested by adding a few drops of hydrogen peroxide to a colony of bacteria, and catalase makes hydrogen peroxide dissociate into water and oxygen, making the mixture foam.
It is also a beta-hemolytic bacteria, because when cultivated on a medium called blood agar, B. cereus colonies cause beta-hemolysis, also called complete hemolysis.
That’s because B. cereus makes a toxin called beta-hemolysin, that causes complete lysis of the hemoglobin in the red blood cells, making the blood agar change color from red to transparent yellow around the colonies
Finally, Bacillus Cereus is a spore-forming bacteria, so it can undergo endosporulation when it feels threatened by the environment, like when the temperature becomes too high or too low, in case of extreme dryness, or when there’s harmful radiation around.
Endosporulation means that the bacteria starts by replicating its DNA, and then it forms a wall inside the cell, isolating a portion from the rest of the cell - let’s call it the mother cell.
Next, the plasma membrane of the cell surrounds the mother cell and then pinches it off, forming a separate body known as a forespore.
The forespore then invaginates into the mother cell and gets completely engulfed by it.
Inside the dying mother cell, the forespore loses water and accumulates calcium, and at the same time gets wrapped in a super tough cortex from the dying mother cell.
Bacillus cereus is a rod-shaped, spore-producing, gram-positive bacterium that's known to cause food poisoning. It can contaminate a variety of foods, including cooked rice, pasta, and potato salad. As a spore-forming bacteria, Bacillus cereus can survive for long periods outside of the body. Symptoms include profuse watery diarrhea, nausea, vomiting, and abdominal cramping. Symptoms usually start within 6 to 15 hours after ingesting contaminated food.
Latest on COVID-19
Nurse Practitioner (NP)
Physician Assistant (PA)
Create custom content
Raise the Line Podcast
Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Cookies are used by this site.
Terms and Conditions
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.