Microbe-Human Interactions

Contact: Microbes adhere to exposed body surfaces

carrier state develops: microbes are established in tissues but disease is not apparent.

Invasion: microbes cross lines of defense and enter sterile tissue

infection: pathogenic microbes multiply in tissues.

Defenses: hold pathogen in check

immunity/ repair of damage

effects of microbes: result in injury or disruption to tissues and morbidity/mortality occur

Microbiota: normal inhabitant, typically don’t cause disease. (mutual commensal relationships)

Pathogens: not normally found in/on the body (parasitic relationships)

Microbiota include: Bacteria, fungi, protozoa, viruses, animals

Microbiota are found wherever the body encounters the environment: skin and mucous membranes, upper respiratory tract, gastrointestinal tract, outer opening of the urethra , external genitalia, vagina, external ear and canal, external eye (lash, lids, follicles)

Areas without normal microbiota: all internal tissue and organs, heart and circulatory system, liver, kidneys and bladder, lungs, brain and spinal cord, muscles, bones, ovaries/testes, glands (pancreas, salivary), sinuses, middle and inner ear, internal ear

Fluids within an organ or tissue: blood, urine in kidneys, ureters, bladder, cerebrospinal fluid, saliva prior to entering oral cavity, semen prior to entering urethra, amniotic fluid surrounding the embryo and fetus

acquisition of microbiota: prior to birth of a fetus is sterile tissue in a sterile fluid, rupture of the amniotic membranes, birth

Microbiota changes when?: first solid food, eruption of teeth, puberty, menopause, long term antibiotic therapy

Microbiota is found: in the upper epidermis, glands and follicles

Names of microbiota found?: staphylococcus , streptococcus , micrococcus, propionibacterium, fungi, arthropods

Microbiota found in the GI Tract: Streptococcus , s. mutans, s. sanguinis

Microbiota found in the Esophagus/stomach/small intestine?: little microbiota

Large intestine: obligate anaroebes, clostridium, facultative anaerobes, E.coli,

Females: microbiota is found on the external genitalia and part of the urethra

Males: support microbiota only in the outermost portion of the urethra