1/26/2016 Microbes Pathology,Infection,and Disease Learning Objective Invisible Invaders Define pathology,etiology,infection,and disease. Amazing Allies Chapter 14 Principles of Disease and Epidemiology Pathology:the study of disease Infection:invasion or colonization of the body by Pathology has three objectives. pathogens presence of a microbe in a 1-Etiology:the cause of a disease part of the body where it is not normally found 2-Pathogenesis:the development of MRSA disease 3-Structural and functional changes brought about by disease and their in effects on the body performing normal functions E.coW 0157:H7 An infection may exist in the absence of detectable disease.No symptoms are apparent
1/26/2016 1 Invisible Invaders Amazing Allies Chapter 14 Principles of Disease and Epidemiology Pathology, Infection, and Disease Learning Objective Define pathology, etiology, infection, and disease. Pathology: the study of disease Pathology has three objectives. 1-Etiology: the cause of a disease 2-Pathogenesis: the development of disease 3-Structural and functional changes broug y ht about by disease and their effects on the body Infection: invasion or colonization of the body by pathogens presence of a microbe in a p y art of the body where it is not normally found Pathogens: disease-causing microorganisms Disease: an abnormal state in which the body is not perf i l f ti forming normal functions An infection may exist in the absence of detectable disease. No symptoms are apparent
1/26/2016 Normal Microbiota Bacterial disease is a rare event Most bacteria are never pathogeric Learning Objectives Qg具 Define normaland transient microbiota. 538 species are known human pathogers Compare commensalism,mutualism,and 0.05%of total bacterial species parasitism,and give an example of each. Contrast normal microbiota and transient Many bacteria have the potential to be microbiota with opportunistic pathogeric microorganisms. Very few bocteria are always pathogenic Requires the human host for survival Many harmless microorganisms establish inside parts of the human body and on Normal Microbiota its surface in microbial communities Transient microbiota may be present for days, called microbiomes weeks,or months Normal microbiota permanently colonize the ·Human body contains host and do not cause disease under normal conditions 1x 1013 human cells Human Microbiome Project 1 x 1014 bacterial cells ween microbial Microbes benefit our health as well as Goal:to understand the relationship between human cause disease
1/26/2016 2 Normal Microbiota Learning Objectives Define normal and transient microbiota. Compare commensalism, mutualism, and parasitism, and give an example of each. Contrast normal microbiota and transient mi bi t ith pp t nisti microbiota with opportunistic microorganisms. Most bacteria are never pathogenic 1 million species of bacteria Bacterial disease is a rare event 538 species are known human pathogens 0.05% of total bacterial species Many bacteria have the potential to be pathogenic Very few bacteria are always pathogenic Requires the human host for survival • Many harmless microorganisms establish inside parts of the human body and on its surface in microbial communities called m crob omes icrobiomes • Human body contains 1 x 1013 human cells 1 x 1014 bacterial cells • Microbes benefit our health as well as cause disease Normal Microbiota • Transient microbiota may be present for days, weeks, or months • Normal microbiota permanently colonize the host and do not cause disease under normal conditions • Human Microbiome Project analyzes relationships between microbial communiti th b d d h h lth ities on the body and human health Goal: to understand the relationship between changes in the microbiome and human health and disease
1/26/2016 Microbes are not found throughout the body but instead are localized in certain regions of the body THE HUMAN MICROBIOME Intestines Urogenita 四 Humans may now be identified by their own Normal Microbiota unique microbial cloud -Nutrients:dead cells,food in the intestines, secreted cellular products,body fluids -Physical and chemical factors:pH,temperature, oxygen levels,carbon dioxide,salinity,sunlight -Host defenses:molecules and activated cells that kill microbes inhibit theirg,prevent adhesion to host cells,neutralize toxins Mechanical factors:chewing,flow of gastric juices,flow of saliva,flushing of urine Microbes can colonize only the body parts that supply the right nutrient
1/26/2016 3 Mouth Microbes are not found throughout the body but instead are localized in certain regions of the body Stomach Skin Respiratory Eyes Intestines Urogenital Humans may now be identified by their own unique microbial cloud Normal Microbiota • Distribution and composition of normal microbiota are determined by many factors – Nutrients: dead cells, food in the intestines, s t d ll l p d ts b d fl ids secreted cellular products, body fluids – Physical and chemical factors: pH, temperature, oxygen levels, carbon dioxide, salinity, sunlight – Host defenses: molecules and activated cells that kill microbes, inhibit their growth, prevent adhesion to host cells, neutralize toxins – Mechanical factors: chewing, flow of gastric juices, flow of saliva, flushing of urine Microbes can colonize only the body parts that supply the right nutrients
1/26/2016 Relationships between the Normal If the balance between the normal microbiota and pathogens is disturbed.disease can occur Microbiota and the Host An example,Clostridium difficile infection,a mild diarrhea Microbial antagonism (competitive to severe to fatal inflammation of the colon.Responsible for exclusion)is a competition between most gastrointestinal infections after antibiotic therapy microbes Normal microbiota protect the host by: -Competing for nutrients -Producing substances harmful to invading microbes -Fecal transplants 。。 -Affecting pH and available oxyger Pills containing fecal bacteric When the balance between the normal mic robiota and pathogens is disturbed,disease can occur
1/26/2016 4 Relationships between the Normal Microbiota and the Host • Microbial antagonism (competitive exclusion) is a competition between mi b s cro e • Normal microbiota protect the host by: – Competing for nutrients – Producing substances harmful to invading microbes – Affecting pH and available oxygen • When the balance between the normal microbiota and pathogens is disturbed, disease can occur. If the balance between the normal microbiota and pathogens is disturbed, disease can occur. • An example, Clostridium difficile infection, a mild diarrhea to severe to fatal inflammation of the colon. Responsible for most gastrointestinal infections after antibiotic therapy -F p ecal transplants - Pills containing fecal bacteria
1/26/2016 Relationships between the Normal SYMRIOGES Microbiota and the Host Commensalism:one organism Symbiosis is the relationship between normal benefits,and the other is microbiota and the host unaffected -Commensalism:one organism benefits,and the Staphylococcus epidermidis other is unaffected that inhabit the skin Mutualism:both organisms benefit the surface of the eye -Parasitism:one organism benefits at the expense mycobacteria that inhabit of the other w四2 the ear Some normal microbiota are opportunistic pathogens These bacteria live on secretions and sloughed off cells but bring no harm to the host L8oog nisms bene m both Parasitism:one organism Escherichia coli that inhabit benefits at the expense of the the large intestine other Many disease-caus baec2earepaasi2 Host absorbs and uses these HIN1 (a new influenza virus) vitamins virus particles on a host cell -In return,the lar used by the bacteria to survive
1/26/2016 5 Relationships between the Normal Microbiota and the Host • Symbiosis is the relationship between normal microbiota and the host – Commensalism: one organism benefits, and the other is unaffected – Mutualism: both organisms benefit – Parasitism: one organism benefits at the expense of the other • Some normal microbiota are opportunistic pathogens – Commensalism: one organism benefits, and the other is unaffected – Staphylococcus epidermidis that inhabit the skin – corynebacteria that inhabit the surface of the eye – mycobacteria that inhabit the ear – These bacteria live on secretions and sloughed off cells but bring no harm to the host Mutualism: both organisms benefit – Escherichia coli that inhabit the large intestine synthesizes vitamin K and some B vitamins – Host absorbs and uses these vitamins – In return, the large intestines provide nutrients used by the bacteria to survive Parasitism: one organism benefits at the expense of the other – Many disease-causing bacteria are parasites – H1N1 (a new influenza virus) virus particles on a host cell