3.1.2 Bacterial Pathogens Flashcards
Explain the significance of Koch’s postulates as they relate to bacterial pathogenesis
What are some of the various types of virulence factors?
Motility, adhesins, invasins, exotoxins, endotoxins (LPS), degradative enzymes, caspsules, siderophores, resistance to antibiotics
What is a virulence factor?
Help bacteria to invade the host, cause disease, and evade host defenses
What are some different forms of adhesion virulence factors?
Pili (fibriae): Type I pili adhere to receptors containing mannose; P pili attach to receptors containing Gal-Gal
Protein adhesins
Biofilms (e.g. plaque)
What are some of the different types of growth associated with invasion and spread?
Extacellularly
Intracellularly (obligate or facultative)
Give three types of invasion of intracellular pathogens
Passive uptake, active invasion, transcytosis
What is the difference b/t exotoxins and endotoxins?
Bacteria-mediated = exotoxins
Host-mediated pathogenesis = endotoxin (LPS, gram - only)
Give four examples of exotoxins
Enzymes, A-B type toxins, membrane damaging toxins, superantigens
What is the role of the different portions of A-B toxins?
B: Binds cell surface receptor
A: ezymatically active and is transported to the cell interior
What are some of the targets of A subunits in A-B toxins?
How do superantigens illicit a response?
What type of toxin is LPS?
Endotoxin
What are three methods to evade the host immune response?
Defensive, offensive, stealth
What are some of the different sample collection methods?
What are the different types of hemolysis seen in blood agar?
What bacteria are associated with pigment formation?
Yellow: Staph aureus
Blue-green: Pseudomonas aeruginosa
Red: Serratia marcescens
What are three different enzymatic tests that can be performed?
Catalase, coagulase, oxidase
What type of microscopy is required to detect spirochetes?
Darkfield microscopy
Describe staining techniques for microscopic examination of bacteria.
Gram stain: most common stain
Acid-fast stain (Ziehl-Neelsen): mycobacteria and other acid-fast microorganisms
Wright-Giemsa stain: chlamydial inclusion bodies, spriochetes, and Rickettsiae
How is a gram stain performed?
How is an acid-fast stain performed?
What are some of the different serology diagnostic techniques?
Immunodiffusion
Latex agglutination
Enzyme-linked Immunosorbent Assay (ELISA)
Western immunoblot
What is ELISA?
How is Western immunoblot performed?
