Chapter 9 Infection Control Concepts PDF

CHAPTER 9 Infection Control Concepts  Objectives (1 of 2) List the classifications of microorganisms, compare their physical structures, and give examples of each. Explain why viral diseases are particularly difficult to treat medically. List six factors involved in the cycle of infection. Defi...

CHAPTER 9 Infection Control Concepts  Objectives (1 of 2) List the classifications of microorganisms, compare their physical structures, and give examples of each. Explain why viral diseases are particularly difficult to treat medically. List six factors involved in the cycle of infection. Define opportunistic infection, list conditions under which these infections may occur, and give examples.  Objectives (2 of 2) Define virulence factors and explain how these factors affect the differences between pathogenic organisms and normal flora. List four possible reservoirs of infection. List three common portals of entry and three portals of exit for pathogenic organisms. List and describe six main routes of infection transmission and name a disease that is transmitted by each route. Discuss and contrast the three basic ways in which the human body is protected from invasion by microorganisms.  Key Terms (1 of 2) Airborne Bacterium Acquired transmissio Antibodies Antigens (pl. resistance n bacteria) Droplet Direct Fungus (pl. contaminati Endospore Fomite contact fungi) on Health care- Natural Normal associated Motile resistance flora infection (HAI)  Key Terms (2 of 2) Opportuni Nosocomia Passive stic Pathogen l infection immunity infection Protozoon Phagocyto Prion (pl. Spore sis protozoa) Virulence Vector Vehicle Virion factors Microorganisms Normal Flora: live on body without Pathogens: cause infections causing infections or disease and disease  Microorgani sms ◦ Bacteria ◦ Grow independently ◦ Does not need host ◦ Sometimes grouped by O2 requirements, shape, or staining process (gram-positive/gram-negative) ◦ Sometimes generate endospores: resistant to heat, cold, and drying ◦ Tuberculosis ◦ Streptococal pharyngitis ◦ Viruses ◦ Smallest known disease-causing organisms ◦ Virion: fully developed particle made of DNA or RNA, covered by capsid ◦ Mutate rapidly, some can resist drying for weeks at a time ◦ Covid ◦ HIV ◦ Hepatitis B Microorgani sms ◦ Fungi ◦ Single-celled yeasts or molds ◦ Yeasts reproduce by forming buds ◦ Molds reproduce with spores ◦ Can be useful in nature, but destructive ◦ Athletes foot ◦ Ring worm ◦ Prions ◦ Least understood and smallest ◦ Infectious proteins? ◦ Cause irreversible neurologic damage ◦ Mad-cow disease ◦ Creuzfeldt-Jakob disease Microorgani sms ◦ Protozoa ◦ Complex single-celled animals exist as free- living organisms ◦ Motile or nonmotile ◦ Trichomoniasis ◦ Toxoplasmosis Cycle of Infection ◦ Infectious organisms ◦ Reservoir of Infection ◦ Portal of exit ◦ Susceptible host ◦ Portal of entry ◦ Transmission of disease Infectious Organisms Microorganisms capable of causing disease are called pathogens or pathogenic organisms. Virulence factors distinguish pathogens from nonpathogenic organisms and normal flora. Table 9-1 in your textbook lists common pathogens.  Place where pathogens can thrive in sufficient numbers to pose a threat Reservoi Must have:Suitable Moisture Nutrient temperat r of s ure Infection What can you think of that fits this description? Portal of Exit Any route through which blood, body fluids, excretions, or secretions leave the body Examples: Open Respirat GI tract wound ory tract Susceptible Host Patients are often hosts because of a reduced immune system. ◦ Nosocomial infection, also called HAI ◦ hospital-acquired infection ◦ health care-associated infection ◦ Considered HAI after 48 hours of admission ◦ Opportunistic infections ◦ Normal flora can cause infections when they are located outside usual environment ◦ When the Host’s immune system is compromised ◦ Healthcare workers are also at risk. (occupationally acquired infections) ◦ Exposure to blood and other bodily fluids Portal of Entry ◦ The route by which microorganisms gain access into the susceptible host ◦ Examples: ◦ Respiratory tract ◦ Urinary tract ◦ GI tract ◦ Open wound or break in skin ◦ Mucous membranes of the eyes, nose, or mouth ◦ Bloodstream Transmissio n of Disease ◦ How a disease travels/infects ◦ Most direct way to break the cycle of infection is to prevent transmission of the infectious organism from the reservoir to the susceptible host Transmission of Disease Direct Indirect ◦Droplet ◦Airborne ◦Direct Contact ◦Vehicle ◦Vector Direct Contact ◦Host is touched by infected person and the organisms are placed in direct contact with susceptible tissue. ◦Requires the pathogens to be placed in direct contact with susceptible tissue ◦Examples: ◦Syphilis ◦HIV infections ◦Staph infections Vectors ◦ An arthropod in whose body an infectious organism develops or multiplies before becoming infective to a new host. ◦ Biological: the disease is ingested by the host where it multiplies and takes several days to be infectious ◦ Mechanical: the disease is carried by the host on mouth/body parts and transferred when the vector lands ◦ Examples: ◦ Mosquitos—malaria Vehicles ◦Any medium that transports microorganisms ◦Examples: ◦Contaminated food, water, drugs, or blood Example: Typhoid fever, Salmonella Fomites- Vehicle Borne ◦ An object that has been in contact with pathogenic organisms ◦ Examples: ◦ Contaminated gloves ◦ X-ray table ◦ Positioning sponges Example: wound infection Droplet Contamination Occurs when an infectious individual coughs, sneezes, speaks, or sings in the vicinity of a susceptible host Involves contact of the mucous membranes of the Droplets do not eyes, nose, or mouth of a travel far (3 feet or host with large droplets less) (greater than 5 µm) that contain microorganisms Droplet Contaminatio n ◦Examples: ◦Influenza ◦Meningitis ◦Diphtheria ◦Pertussis ◦Streptococcal pneumonia ◦Covid Airborne ◦ Occurs from dust that contains spores or by means of droplet nuclei ◦ Droplet nuclei are particles of evaporated droplets containing microorganisms and measuring 5 microns (micrometers, µm, 0.001 mm) or smaller. ◦ Can remain suspended in the air for long periods Airborne ◦Examples: ◦TB ◦Varicella viruses (also transmitted via direct contact) ◦Covid  The Body’s Defense Against Infection ◦Natural Resistance ◦ Provided by mechanical barriers of intact skin and mucous membranes ◦ Phagocytosis: inflammation increasing blood flow and permitting the passing of fluids and white blood cells into tissues to engulf and destroy the invading pathogens ◦Acquired Immunity (long term) ◦ Occurs when an individual develops antibodies to a particular organism as a result of either infection or immunization ◦Passive Immunity ◦ Occurs following an injection of preformed antibodies to a particular infection The Body’s Defense Against Infection ◦ Antigens: a foreign substance that enters the body ◦ Antibodies: protein substances formed in response to specific antigens ◦ If you develop your own antibodies, it is acquired/long term immunity. ◦ If you receive a vaccine of preformed antibodies, it is passive/shorter term immunity. QUIZ What are fungi(fungus)? a. Single-celled yeasts b. Filament-like structures called molds c. Both a and b d. Neither a nor b What is a fully developed virus particle called? a. Prion b. Endospore c. Bacteria d. Virion A virus is covered by a coating called _ a. Envelope b. Capsid c. Spore d. None of the above A capsid may be covered by a lipoprotein envelope with spikes a. True b. False What is a complex single-celled animal referred to as? a. Bacteria b. Spore c. Protozoa d. None of the above The process of inflammation increasing blood flow that allow passage of white blood cells into tissues to engulf and destroy invading pathogens is termed? a. Phagocytosis b. Path cytosis c. Cell cytosis d. None of the above BONUS!!! Tuberculosis is caused by a: a. Fungi b. Virus c. Prion d. Bacteria BONUS 2!!!! An endospore is a. A resistant form of the bacterium that is produced within the cell when environmental conditions are unfavorable b. Opportunistic infections relating to fungi and yeasts c. A protein covered coating for a viral particle d. A form of motile protozoa