1 / 10

Bacteriology

Bacteriology. Gram positive cocci. Gram positive rods. “big 4”. Gram negative cocci. Gram negative rods. Acid-fast bacteria. Spirochetes. The Chlamydia. The Rickettsia. The Mycoplasmas. Staphylococci. gram-positive cocci , occurring singly, in pairs, tetrads, or grapelike clusters

lave
Download Presentation

Bacteriology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Bacteriology Gram positive cocci Gram positive rods “big 4” Gram negative cocci Gram negative rods Acid-fast bacteria Spirochetes The Chlamydia The Rickettsia The Mycoplasmas

  2. Staphylococci • gram-positive cocci, occurring singly, in pairs, tetrads, or grapelike clusters • facultative anaerobes and usually catalase positive • normal inhabitants of upper respiratory tract, skin, intestines and vagina • Staphylococcus aureus – coagulase positive, pathogenic • S. epidermidis – coagulase negative, less pathogenic • found on implanted medical devices • S. saprophyticus – coagulase negative, urinary tract infections only Pyogenic (pus forming)

  3. Abscess = local collection of pus Development involves both bacteria and host factors Early: acute inflammatory response (neutrophils) Some neutrophils lysed by bacteria (neutrophil contents damaging) Host surrounds area with thick-walled fibrin capsule Blood supply is cut off Center of abscess necrotic Dead neutrophils, dead and live bacteria Edema fluid Problems if abscess located in a vital area of the body.

  4. Humans are the major reservoir for S. aureus Binding of Staphylococci to human hosts several human proteins are targets for binding fibronectin (FNBP) collagen IV sialoprotein laminin Staphylococci defenses against neutrophils capsule peptidoglycan teichoic acid protein A slime

  5. Slime • many pathogenic strains are slime producers • viscous extracellular glycoconjugate that allows bacteria to adhere to smooth surfaces and form biofilms • inhibits neutrophil chemotaxis, phagocytosis, and antimicrobial agents slime

  6. Enzymes and toxins produced by Staphylococci

  7. Toxic shock syndrome • caused by S. aureus strains that release toxic shock syndrome toxin and other toxins • most cases occur in females who use superabsorbent tampons • clinical manifestations • low blood pressure, fever, diarrhea, extensive skin rash, and shedding of skin Scalded skin syndrome (SSS) • caused by strains of S. aureus that carry a plasmid-borne gene for exfoliative toxin (exfoliatin) • epidermis peels off revealing red area underneath Food poisoning • caused by enterotoxins (even in absence of organism) • heat stable toxins • intensive intestinal peristalsis

  8. Staphylococcal diseases • treatment, prevention, and control • isolation and identification based on catalase test, coagulase test, serology, DNA fingerprinting, and phage typing • draining abscesses • antibiotic therapy • many drug-resistant strains • use semisynthetic penicillins and cephalosporins • vancomycin, if necessary • other antibiotics • personal hygiene, food handling, and aseptic management of lesions

More Related