Staphylococcus aureus evades our humoral immune response by the use of its Protein A on the outer surface. When the Immunoglobulins (Ig's, or antibodies) show up, they can't bind to the bacterium in the normal way. The Fc portion of the Ig is bound to Protein A, and it is supposed to be on the outside so the PMN, polymorphonuclear leukocyte, aka white blood cell specialized for macrophage duty, can bind to it. But with the Fc spot bound, the PMN can't engulf the bacteria and the complement cascade is not activated.
The complement cascade is a biochemical chain reaction which helps clear pathogens from an organism. Part of the larger general immune system, it is not adaptable and does not change over the course of an individual's lifetime; as such it belongs to the innate immune system. However, it can be recruited and brought into action by the adaptive immune system. The complement system consists of a number of small proteins found in the blood, normally circulating as inactive zymogens. When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages. The end result of this activation cascade is massive amplification of the response and activation of the cell-killing membrane attack complex. Over 20 proteins and protein fragments make up the complement system, including serum proteins, serosal proteins, and cell membrane receptors. These proteins are synthesized mainly in the liver, and they account for about 5% of the globulin fraction of blood serum. Three biochemical pathways activate the complement system: the classical complement pathway, the alternative complement pathway, and the mannose-binding lectin pathway.
cytokines = a group of proteins and peptides that are signalling compounds that act via cell-surface cytokine receptors. Mainly smaller (8--30 kDa) water-soluble proteins and glycoproteins, they act like hormones and neurotransmitters but are released by many types of cells (both haemopoietic and non-haemopoietic). Central role in the immune system, also involved in embryogenesis. When the immune system is fighting pathogens, cytokines signal immune cells such as T-cells and macrophages to travel to the site of infection. In addition, cytokines activate those cells, stimulating them to produce more cytokines.
pyogenic = pus producing
pyrogenic = fever producing
AGN = acute glomerulonephritis, may show up 2-3 weeks after strep A infection (not all strains but more common after a skin infx than a sore throat), S/Sx include: a drop in BP, edema of face & ankles, smoky colored urine (RBC's in the urine), the disease is mediated by antigen-antibody complexes on the glomerular basement membrane, too late for antibiotics, could have been prevented by antibiotics early in infx.
S/Sx of imflammatory gastroenteritis: fever, severe gut pain, cramping, tenesmus, bacterial multiply in colon & ileum, PMN leucocytes in stool, responds to absorbable and parenteral antibiotics. Some critters that can cause it: Campylobacter jejuni, EHEC, Shigella, Salmonella. These four are routinely cultured from stool sample.
parenteral = drug that is NOT swallowed into the gut, but needed systemically
enteral = drug given via digestive tract for systemic effect
topical = drug is applied directly where local action is needed. is absorbable similar to this?
vesical tenesmus = difficult or failed attempts to urinate despite the bladder feeling full. As opposed to just regular tenesmus, which is understood to be rectal.
non-inflammatory diarrhea = caused by a toxin but the bacteria don't invade, usu remains in the small intesting and there is no systemic immune response so not leukocyctes in the poop. Vibrio cholera, ETEC and EPEC cause this. Osmotic.. Only EHEC canNOT ferment sorbitol, use EMB agar.
Klebisiella = opportunistic normal flora found in the GI tract, oral mucosa, skin and soil, attacks mainly the immunosuppressed, pathogenic due to capsular antigens
Proteus = gram negative rectangular thing causing UTI's & pneumonia in immune-compromised individuals. Produces urease which alkalinizes uring, precips salts to form struvite stones