Chapter 16: Host-Microbe InteractionsVocabulary:Normal microbiota: population of microorganisms that routinely reside on the body’s surfacesColonization: establishment and growth (multiplication) of a microorganism on the body surfacePathogen: microorganism/infectious agent capable of causing disease in a healthy individual. Invasion/toxinsImmunocompromised: 2^ to diabetes (DM), malnutrition, cancer, AIDS, dz (disease), surgery, wounds, genetic defects, alcohol (EtOH)/drug abuse, transplant, RxAnatomical Barriers- Skin and mucous membranesMutualism- Both partners benefit- Bacteria/ large intestineCommensalism- Association in which one partner benefits and other is unharmed- Bacteria/skinParasitism- Association in which parasite derives benefit at expense of host- Pathogen = parasiteNormal Flora- Defined as population of microorganisms routinely found growing on the body of healthy individual- Commensals- 1) Protect against potentially harmful organisms by competing with pathogenso Covering binding sites used for pathogenic attachmento Tropism = attachmento Consume available nutrientso Produce toxic compounds such as antibiotics - 2) stimulation of the immune system- If killed or grown suppressed, pathogens may colonize and cause diseaseo Antibiotics/clostridium difficile Nosocomical/HAI: hospital acquired infection Endospore Chronic diarrhea o Opportunistic infection: normal flora may infect host- Resident flora inhabit body sites for extended periods- Transient flora are temporaryo They form associations for a short time and are replaced- Both resident and transient flora do NOT interfere with normal body functionsDynamic Nature of Normal Flora- Human fetus is sterile until amniotic sac ruptures- Normal flora established – passage through birth canal- Composition is dynamicPrinciples of Infectious Disease (16.3)- If colonized organisms have parasitic relationship with host, the term infection applies- Infection does not always lead to noticeable adverse effects- Infection: growth and multiplication of parasitic organism/virus in or on the body of the host +/- production of disease- Subclinical/in apparent infection: Sx non-existent or mild - Carrier state: person with asymptomatic infection, or who has recovered from an infection but continues to carrythe organism and may shed it- Infection disease (ID): infection that results in disease- Disease: process resulting in tissue damage or noticeable impairment of body functiono Characterized by signs and symptoms- One infectious disease may leave individual predisposed to developing new disease- Primary infection = initial disease- Secondary infection = additional infection resulting from primary infection- 1^ viral URI –> 2^ bacterial pneumonia.o Pneumonia: death by drowning- Influenza  Haemophilus influenzaeo Pandemic: world-wideo Interferons: natural defense against viral infections-Symptomso Subjective indication of diseaseo Effects of a disease experienced by the patiento Any morbid phenomenon or departure from the normal in structure, function, or sensation experienced by the patiento Pain, nausea, malaise, headacheSignso Objective: abnormality indicative of diseaseo Effects of the disease observed by examining the patiento Exanthema, pus, edema, fever,