Bacterial Characteristics Quiz

Biological Characteristics and Pathogenic Materials of Bacteria

• Endotoxin is released after destruction of the bacterial cell wall.
• Pigments can be used for identifying bacteria.
• Bacteriocin is a bactericidal protein produced by many bacteria to inhibit the growth of similar or closely related strains.
• Only bacteria and archaea have the enzymes required for Vitamin B12 synthesis.
• Colony is a visible mass of microorganisms, all originating from a single mother cell, that constitutes a clone of bacteria all genetically alike.
• Staphylococci are divided into two types: coagulase positive (S. aureus) and coagulase negative.
• Streptococci are widely distributed in nature and may be capsulate and arranged in chains or pairs.
• Streptococcus pneumoniae is a diplococcus or pneumococcus that has different types of capsules and is associated with pneumonia.
• Neisseriae are gram-negative cocci that usually occur in pairs and can be found associated with or inside polymorphonuclear cells.
• Pili are thin, hair-like structures on the surface of some bacteria that enable them to attach to surfaces or other bacteria, exchange genetic material, and move.
• Major virulence factors of Streptococcus include cell surface structure and invasiveness, such as lipoteichoic acid and M protein.
• Major virulence factors of S. aureus include coagulase, hemolysins, leukocidin, exfoliative toxin, and toxic shock syndrome toxin-I.

Microbial Pathogens: Streptococci, Neisseriae, and Staphylococci

• Streptococci are widely distributed in nature, some of which are members of the normal human flora, while others are associated with important human diseases.
• Streptococcus pneumoniae is important for causing pneumonia and is characterized by G+ lancet-shaped cocci arranged in pairs and alpha hemolysis.
• Neisseriae are gram-negative cocci that usually occur in pairs and are most commonly found in polymorphonuclear cells.
• Neisseria gonorrhoeae and Neisseria meningitidis are pathogenic for human beings and typically found associated with or inside polymorphonuclear cells.
• Staphylococci are characterized by being about 1 μm in diameter, G+ cocci, and grape-like clusters.
• Staphylococci grow on most bacteriologic media and produce pigments, with S. aureus colonies being deep yellow and S. epidermidis colonies being white to gray.
• Major virulence factors of Streptococcus include cell surface structure, invasiveness, hyaluronidase, and streptokinase.
• Major virulence factors of Staphylococcus include coagulase, hemolysins, leukocidin, exfoliative toxin, and toxic shock syndrome toxin-I.
• Coagulase production is considered synonymous with invasive pathogenic potential in Staphylococcus, while Coagulase-negative Staphylococcus is an opportunistic bacterium that causes urinary tract infections, wound infections, bacteremia, and septicemia.
• Pili, outer membrane proteins, IgA protease, and capsules are important pathogenic materials for Neisseria.
• Diseases caused by Streptococcus include pyogenic infections, toxic diseases like scarlet fever and streptococcal toxic shock syndrome, and allergic diseases like acute glomerulonephritis and rheumatic fever.
• Streptococcus pyogenes is responsible for pyogenic infections like tonsillitis, otitis media, nasopharyngitis, nasosinusitis, and necrotizing fasciitis.