IS LEC LE 1

• Pathogens have a high probability of causing an infection, but under unusual circumstances any microorganism, even non-pathogens, might be capable of causing an infection.
• Mechanisms of fever: to burn everything; to increase your body temperature so that all the bacteria will die.
• The likelihood of catching a disease depends on the pathogen’s number and invasiveness, your health, nutrition, and immune status, and the portals of entry.
• Organisms are highly selective in their choice of tissues in the host they infect, and their metabolic requirements and protective characteristics contribute to this selection.
• Most organisms are tissue or organ specific, and some are even host-specific.
• Symbiosis in which both members benefit from the relationship is known as mutualism.
• A relationship in which one member benefits, and the other one is harmed in some way is known as parasitism.
• A relationship in which one member benefits, and the other one neither benefits nor harmed is known as commensalism.
• Infectious disease is a set of signs and symptoms of pathogenic illness caused by microorganisms.
• Pathogenic refers to the ability of an organism to cause a disease.
• Virulence is the degree or intensity of pathogenicity; an attribute generally ascribed to a strain.
• Contamination is the presence of microorganisms such as Fomites and food.
• Infection is when parasitic microorganisms increase in number either within or on the body of the host.
• The human adult is estimated to have 30 trillion human cells and 38 trillion bacterial cells in their body.
• Antagonism is competition and the production of inhibitors (bacteriocins) produced by bacteriocins, which are bactericidal barriers that help produce the levels of contaminating bacteria.
• Several probiotic cultures produce bacteriocins and there is good evidence that can help with your gut microflora.
• Adhesins are capsule-adhesion and coating to evade from phagocytosis, as seen in Streptococcus pneumonia, Klebsiella pneumoniae, Streptococcus mutans.
• Tetanus, botulism, anthrax, pseudomonas infections, a variety of fungi are examples of infections from non-living source reservoirs.
• Rabies, plague, leptospirosis, Lyme disease, toxoplasmosis, psittacosis, salmonella, food poisoning are examples of living source infections.
• Mechanical transmission is when the animal host picks up the microbes and moves them around, as seen in cockroaches, lizards, or flies landing on feces or dead animals.
• Biological transmission is when the animal host is needed by the microbe for some metabolic or other essential process, such as in malaria, Lyme disease, sleeping sickness, and the plague.
• Contact transmission, vehicle transmission, and vector transmission are modes of transmission for non-living source infections.
• The outer membrane in gram (-) bacteria contains endotoxin (LPS), as seen in E. coli.
• Water is a common reservoir for non-living source infections such as giardiasis, typhoid fever, amebiasis, leptospirosis.
• Neuraminidase dissolves neuraminic acid, an important mucus component, as seen in Influenza virus.
• Fimbriae (pili) are often tissue-specific, as seen in Escherichia coli, Bordetella pertussis, Neisseria gonorrhea, Streptococcus pyogenes.
• The cell wall in some bacteria have virulence-promoting properties, as seen in Streptococcus pyogenes, Staphylococcus aureus, Mycobacterium tuberculosis.
• If normal flora is destroyed, conditions such as Staphylococcal enteritis and Pseudomembranous colitis can occur.
• Mutualism is a symbiosis in which both members benefit from the relationship.
• Parasitism is a relationship in which one member benefits, and the other one is harmed in some way.
• Normal flora behaves as an antigen, inducing the production of low levels of antibodies that can cross react with similar antigens and pathogens, preventing infection or invasion.
• Production of nutrients Vitamin B and K in the intestines by E coli stimulates maturation of the immune system.
• Septiceemia is when bacteria are actually growing and multiplying in your blood.
• Nosocomial infections can be prevented if you know how to stop the Chain of Infection.
• Opportunists can cause disease if they get into the wrong place, such as E coli normally found in the intestine, but can cause infection if found in the bladder (UTI) or peritoneal cavity; such as when one sees peritonitis after a ruptured appendix.
• Latent bacteremia is when an agent remains inactive then reactivates, examples include TB, toxoplasmosis, shingles.
• A disease that is not spread from one host to another is a non-communicable disease, examples include tetanus, food poisoning, subacute bacterial endocarditis, etc.
• Many hospital organisms are resistant to antibiotics, and nosocomial infections can occur to patients who are immune-compromised (by disease, injury, or chemotherapy).
• The source of the organism can be a human source, such as a sick human with an acute illness that will get better or die, or a carrier with inapparent infections, subclinical infection, or chronic infection.
• Bacteremia is the presence of bacteria in the blood.