Microorganisms and Disease: Normal Flora (BIOL2010-Week9-F24)

www.udst.edu.qa Microorganisms and Disease: Normal Flora Microorganisms and Disease Humans have 30 trillion cells in their body Humans are covered with 40 trillion microorganisms!!! Can include bacteria, fungi, protozoans, and viruses This population constitutes our Normal Flora o...

www.udst.edu.qa Microorganisms and Disease: Normal Flora Microorganisms and Disease Humans have 30 trillion cells in their body Humans are covered with 40 trillion microorganisms!!! Can include bacteria, fungi, protozoans, and viruses This population constitutes our Normal Flora or Human Microbiota The normal flora is a mixture of pathogenic and harmless organisms Comprised of resident and transient microflora Normal flora do not cause disease Symbiosis and Normal Flora Do not typically cause illness in humans IF you have a healthy immune system Can become opportunistic and invade the system of individuals Those with immune deficiencies, elderly, etc. Example: Bacteria of the nose include Streptococcus pneumoniae and Staph aureus Generally benign and cause no issues If they colonize other areas of the body they can be highly pathogenic and KILL Human Microflora Benefits of the human microflora Include chemical secretions such as vitamin B & K Stimulates the immune system Assists with the recognition of foreign bodies Prevents pathogenic bacteria from colonizing tissue Produce bacteriocins Large Intestine: Bifidobacterium – probiotic Escherichia coli Bacterioides Lactobacillus Opportunistic Bacteria Humans can be infected with MOs that seize an advantage Weakened immune system, wounds, altered microbiota Generally do not cause disease in humans but Introduction to areas where they should not be found Lack of competition from commensals Cause infection and disease Agents such as: Pseudomonas aeruginosa Salmonella spp. Streptococcus/Staphylococcus Symbiosis and Normal Flora The location of normal flora can be as follows: Human skin Armpits/Groin/Soles of Feet Hair Follicles/Sweat Glands Respiratory tract Nose/Nostrils Buccal Area Digestive System Urogenital Tract Symbiosis and Normal Flora The location of normal flora depend on several factors: Moisture level pH level Temperature Salinity The presence of waste products Presence of Microbes Symbiosis and Normal Flora The Integument The human skin is a dynamic surface Has a variety of different textures and thicknesses Some areas are more moist than others Moist areas support more growth Dry areas support less growth There are also differences in the pH of skin Pits such as hair follicles and sweat glands bloom anaerobes Armpits/Groin/Soles of the Feet and Hands Symbiosis and Normal Flora The Respiratory Tract – Two divisions: Upper Respiratory Tract: Nose Nasal passages Pharynx (throat) Larynx (“voice box”) Lower Respiratory Tract: Trachea Bronchi Bronchioles Lungs Symbiosis and Normal Flora URT is moist and supports microorganism blooms Most infections are viral in nature Some cases infection is bacterial, fungal, or helminth Many defenses in place to remove pathogens and minimize Cilia filter out and remove organisms Mucous works with the cilia to remove pathogens Hair in nose filters and removes LRT is normally clear of pathogens Damage to area can allow introduction of MO’s Smoking, air pollution, certain gases Symbiosis and Normal Flora Nose / Nostrils Lots of bacteria there but little known about beneficial function Lots of work done to catalogue those living there Staphylococcus aureus Streptococcus pneumonia Symbiosis and Normal Flora Buccal Area Between 100 and 200 species >100,000 living on each tooth surface Streptococci make up the bulk of the species Most are beneficial Streptococcus mutans main cause of tooth decay Mouth contains lots of nutrition and secretions Moist, pH, temperature Support bacterial growth Symbiosis and Normal Flora The Digestive Tract The flora of the digestive tract is affected by several factors Your age The type of diet that you consume Type and frequency of medications Cultural and lifestyle conditions Fast food versus Home Cooking Type of dietary intake Smoking Stress Obesity Geographic location Symbiosis and Normal Flora Stomach is first line of defense against invasive flora Gastric juice contains enzymes and HCl Kill and disrupt the growth of bacteria Some bacteria highly adapted to live in the low pH Helicobacter pylori The small intestine has bacteria in the jejunum and ileum Staphylococcus, Lactobacillus, & Streptobacillus Colon (large intestine) contains the highest numbers of pathogens Mostly opportunistic - E. coli >600 species in the colon Anaerobes live in the colon and digest wastes in the bowel ~50% of your fecal mass is bacteria Symbiosis and Normal Flora Urogenital System Contains your urinary and reproductive systems Generally kidneys, ureters, urethra and bladder are sterile The opening of the urethra to the outside has microbes Generally comprised of bacteria, fungi and viruses Constant flushing of urinary tract prevents buildup Prevents infections UTIs occur from change in normal flora or blockages Infection from inflammation