PMHS - Pittsford Central School District



PMHS Name ____________

Microbiology – Mr. Mauks Date ____________

Guided Notes Microbe-Human Interactions: Infection and Disease

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Healthy?

• Infection- a condition in which ______________________________________ _________________________________________________________________

• Disease – ________________________________________________________ _________________________________________________________________

Resident flora

• includes bacteria, fungi, protozoa, viruses and arthropods

• ________________________________________________________________ harbor resident microbes; large intestine has the highest numbers of bacteria

• internal organs & tissues & fluids are _______________________

• bacterial flora benefit host by ________________________________________ ___________________________________________________________

Landscape of the skin

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Distribution of flora

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Pathogen

• True pathogens – _______________________________________________ ___________________________________________________________

– Influenza virus, plague bacillus, malarial protozoan

• Opportunistic pathogens – _______________________________________ ____________________________________________________________

– Pseudomonas sp & Candida albicans

Overview of infection

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Portals of entry

• skin

• gastrointestinal tract

• ________________________________

• ________________________________

Infectious dose (ID)

• ___________________________________________________________

• microbes with small IDs have greater virulence

– 1 rickettsial cell in Q fever

– 10 bacteria in TB, giardiasis

– 109 bacteria in cholera

• ______________________________________________________________

Mechanisms of adhesion

• ________________________

• flagella

• ____________________________________________

• cilia

• suckers

• hooks

• barbs

Mechanisms of adhesion

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Virulence factors

• exoenzymes – ______________________________________________________

• Toxigenicity – capacity to produce toxins at the site of multiplication

– endotoxins – lipid secreted by gram-negative bacteria

– exotoxins – proteins secreted by gram-positive and gram-negative bacteria

• antiphagocytic factors – _____________________________________________, include leukocidins and capsules

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Patterns of infection

• localized infection– ______________________________________________ ______________________________________________

• systemic infection– ________________________________________________ __________________________________________________

• focal infection – when infectious agent breaks loose from a local infection and is carried to other tissues

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Patterns of infection

• Mixed infection – _____________________________________________

• Primary infection – __________________________________________

• Secondary infection – _________________________________________

• Sign – _____________________________ of disease as noted by an observer

• Symptom – ____________________________ of disease as sensed by the patient

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Portals of exit

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Portals of exit

• __________________________________

• ________________________________________

• Fecal exit

• Urogenital tract

• Removal of blood

• Sequelae – ______________________________________________________________

Epidemiology

• The study of the _______________________________________________ _____________________________________________________________

• Surveillance –collecting, analyzing, & reporting data on rates of occurrence, mortality, morbidity and transmission of infections

• Reportable, notifiable diseases must be reported to authorities

CDC

• Centers for Disease Control and Prevention (CDC) in Atlanta, GA – principal government agency responsible for keeping track of infectious diseases nationwide

•

• Prevalence – ____________________________________________________ _______________________________________________________________

• Incidence – _____________________________________________________ ______________________________________________________________

Mortality VS Morbidity

• Mortality rate – ____________________________________________________

• Morbidity rate – ____________________________________________________

A Spreading Menace

• Endemic – disease that exhibits a _____________________________________ _________________________________________________________________

• Sporadic – when occasional cases are __________________________________

• Epidemic – when prevalence of a disease is ______________________________

• Pandemic – epidemic ______________________________

Patterns of disease occurrence

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Reservoirs of infection

• Primary habitat in the natural world from which a pathogen originates

• Living reservoirs ________________________________________________

– Asymptomatic carriers

– Passive carriers

– Vectors – __________________________________________________

• Nonliving reservoirs – ________________________________

Types of carriers

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Vectors

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Patterns of transmission

• __________________________________________

• Indirect contact

– Vehicle – inanimate material, food, water, biological products

– Airborne – droplet nuclei, aerosols

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Nosocomial infections

• Diseases that are acquired _____________________________________

• Most commonly involve urinary tract, respiratory tract, & surgical incisions

• Most common organisms involved ____________________________________, E. coli, Pseudomonas, Staphylococcus

Nosocomial infections

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Koch’s postulates

1. Find evidence of a particular microbe in every case of a disease

2. Isolate that microbe from an infected subject and cultivate it artificially in the laboratory

3. Inoculate a susceptible healthy subject with the laboratory isolate and observe the resultant disease

4. Re-isolate the agent from this subject

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