0
What else can I help you with?
Is shigella indole positive?
Shigella species are generally indole negative, except for Shigella flexneri, which can be indole positive depending on the specific strain. In laboratory identification, indole testing is used to differentiate between various enteric bacteria. Therefore, while most Shigella species do not produce indole, Shigella flexneri may show positive results under certain conditions.
What is the colony morphology for shigella?
Shigella typically forms small, colorless or pale colonies on non-selective media like nutrient agar, as it is non-lactose fermenting and does not produce acid. On selective media such as MacConkey agar, Shigella appears as colorless colonies, while on XLD (Xylose Lysine Deoxycholate) agar, it may produce red colonies due to the inability to ferment xylose. The colonies are generally smooth, shiny, and convex in shape.
Is shigella autotrophic?
No, Shigella is not autotrophic; it is a pathogenic bacterium that is heterotrophic. This means it cannot produce its own food through processes like photosynthesis or chemosynthesis and instead relies on organic compounds from its environment, particularly from the host it infects. Shigella primarily obtains nutrients by invading and multiplying within the intestinal cells of its host, leading to gastrointestinal disease.
How does shigella dysenteriae attack and make people sick each year?
Shigella dysenteriae attacks the human gastrointestinal tract, primarily through ingestion of contaminated food or water. Once inside the intestines, it invades epithelial cells, multiplying and causing cell death, which leads to inflammation and ulceration of the intestinal lining. This results in symptoms such as severe diarrhea, abdominal pain, and fever. The bacterium can also produce toxins that exacerbate the illness and can spread easily, contributing to outbreaks, especially in areas with poor sanitation.
What does shigella do to the human body?
Shigella causes dysentery that results in the destruction of the epithelial cells of the intestinal mucosa in the cecum and rectum. Some strains produce enterotoxins and Shiga toxin, similar to the verotoxin of E. coli. Both Shiga toxin and verotoxin are associated with causing hemolytic uremic syndrome.
Is shigella dysenteria positive for starch hydrolysis?
Shigella dysenteriae is generally considered negative for starch hydrolysis. In laboratory tests, it does not produce the enzyme amylase, which is required to hydrolyze starch into simpler sugars. Therefore, when inoculated on starch agar, it typically does not show a clear zone of hydrolysis around the colonies.
What test will differentiate between Salmonella enteridis and Shigella sonnei?
To differentiate between Salmonella enteritidis and Shigella sonnei, the triple sugar iron (TSI) agar test can be used. Salmonella enteritidis typically produces hydrogen sulfide (H2S), resulting in black colonies on TSI agar, while Shigella sonnei does not produce H2S and will not change the color of the agar. Additionally, biochemical tests such as urease and indole tests can further help distinguish between the two, as Shigella sonnei is urease negative and indole positive, while Salmonella enteritidis is urease negative and indole negative.
Most heart attacks are sudden but one in four?
produce no symptoms
What virus attacks the cells in the immune system that produces that antibodies?
HIV, human immunodeficiency virus, is the virus that attacks the cells in the immune system that produce antibodies.
What bacteria are non-lactose ferment er?
Mnemonic: KEE Klebsiella pneumoniae Enterobacter cloacae E. coli Shigella sonnei can ferment lactose, but only after prolonged incubation and so it is referred to as a '''''late-lactose fermenter'''''. Vibrio cholerae is also a late lactose fermenter.
What bacteria produces enterotoxins?
Several bacteria produce enterotoxins, including Staphylococcus aureus, Clostridium perfringens, Vibrio cholerae, and Escherichia coli. These enterotoxins can cause gastrointestinal illnesses, such as food poisoning and diarrhea, when ingested.
What virus in the body attacks the cells in the immune system that produce antibodies?
HIV, human immunodeficiency virus, is the virus that attacks the cells in the immune system that produce antibodies.
