What is the characteristics of Bacillus anthracis?
Bacillus anthracis is a large (1–1.5×3–10 μm) gram-positive sporulating rod, with square or concave ends. It can readily grow on sheep blood agar leading to the formation of rough gray white colonies of 4 to 5 mm, with characteristic comma-shaped or “comet-tail” protrusions (Pile et al., 1998).
What are the characteristics of Bacillus?
Bacillus species are rod-shaped, endospore-forming aerobic or facultatively anaerobic, Gram-positive bacteria; in some species cultures may turn Gram-negative with age. The many species of the genus exhibit a wide range of physiologic abilities that allow them to live in every natural environment.
What is the role of lecithinase?
Lecithinase is a type of phospholipase that acts upon lecithin. perfringens alpha toxin (lecithinase) causes myonecrosis and hemolysis. The lecithinase of S. aureus is used in detection of coagulase-positive strains, because of high link between lecithinase activity and coagulase activity.
What is lecithinase test?
Lecithinase test or Nagler’s reaction is a biochemical test used to identify organisms that liberate phospholipases (lecithinases) e.g. Clostridium perfringens. perfringens has phospholipase activity and hence, helps in the differentiation of C. perfringens from other Clostridium spp that also produce lecithinase (C.
What is unique about Bacillus anthracis?
Bacillus anthracis is a Gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent (obligate) pathogen within the genus Bacillus. Its infection is a type of zoonosis, as it is transmitted from animals to humans.
What disease does Bacillus cause?
Bacillus cereus is a foodborne pathogen that can produce toxins, causing two types of gastrointestinal illness: the emetic (vomiting) syndrome and the diarrhoeal syndrome. When the emetic toxin (cereulide) is produced in the food, vomiting occurs after ingestion of the contaminated food.
Which organism is lecithinase positive?
In identification of Clostridium perfringens, Staphylococcus aureus, Pseudomonas aeruginosa or Listeria monocytogenes . The lecithinase activity of S. aureus is used in detection of coagulase-positive strains, because of high link between lecithinase activity and coagulase activity.
What is egg yolk agar used for?
Egg Yolk Agar (EYA) is an enriched, nonselective, and differential medium used for the presumptive differentiation of Clostridium spp. and other obligate anaerobes.
What are the physical characteristics of Bacillus anthracis?
Bacillus anthracis — Key Characteristics. Large, box-car shaped, gram-positive rod in short or long chains. Non-swelling, oval spores formed when grown on culture media. (Not usually seen in clinical specimens.) Encapsulated rods may be seen in clinical specimens. Ground-glass appearance of colonies. Nonhemolytic on sheep blood agar. Nonmotile.
How can lecithinase be used to identify Bacillus?
Identification of Bacillus species using Mannitol Egg Yolk Polymixin agar. Bacillus cereus, a strong lecithinase positive organism, can be identified using Mannitol-egg yolk-polymyxin (MYP) agar plates.
Which is Lecithinase Positive bacteria in MYP agar?
B. cereus is typically mannitol-negative, produce pink-red colonies in MYP agar with a zone of precipitate around the colonies, indicating lecithinase-positive activity. Bacillus subtilis, is also an aerobic spore producing bacterium, and non-pathogenic to humans.
What are the characteristics of a Gram positive bacillus?
Large, box-car shaped, gram-positive rod in short or long chains. Non-swelling, oval spores formed when grown on culture media. (Not usually seen in clinical specimens.) Encapsulated rods may be seen in clinical specimens.