Health Skills I Student Lecture Packet

Health Skills I

Unit 101Infection Control

Objectives

• Identify the nature of microorganisms, how organisms grow, their transmission, body defenses of the human host, and related terminology

Unit 101.1Microorganisms

• Anton Van Leeuwenhoek– first observed

microorganism under a microscope in 1693

Microorganisms are Everywhere!

• inside and outside our bodies• in food, air, and water• some are useful– fermentation of food

• small percentage cause disease• organisms can be spread• healthcare workers need to understand how

to break cycle

Exciting Moments in Microbiology• Ignatz

Semmelweiss 1860

• reduced the transmission of puerperal fever by handwashing

More Exciting Moments in Microbiology

• LOUIS PASTEUR 1861

• proposed the “Germ Theory”

Definitions• Microorganism– microscopic living things that individually are

too small to be seen with the naked eye, only seen under microscope • example: germs & microbes

• Pathogen– microorganisms capable of causing disease

Definitions• Communicable disease– a pathogenic organism passed from one host

to another• Host – one infected with a pathogenic microorganism

• Susceptible host– one unable to fight off infection due to low

resistance

Definitions

• Colonized – presence of microorganisms in or on a patient,

without clinical signs and symptoms• Infection– colonization invasion of body tissues by

disease producing pathogenic microorganisms• Re-infection – infected a second time by same pathogen

Definitions

• Cross infection – spread to another person by air currents or

health worker• Co-infection – infected with more than one organism

• Secondary infection – an infection acquired following a primary

illness• Nosocomial – infection acquired within a healthcare facility.

Pathogenic OrganismsVirus

• acellular– cannot survive independently

• parasite – can only survive on living tissue– cannot be treated by antibiotics, may use

antiviral drugs– vaccinations can prevent a number of viral

infections

Pathogenic OrganismsVirus

• Examples: – polio, influenza,

common cold, HIV, Hepatitis B, mumps, herpes

Bacteriophage (virus that infects bacteria)

Pathogenic OrganismsBacteria

• simple unicellular organism– three shapes

• coccus, bacillus, spirillium

• Clostridium tetani– bacterium that causes

tetanus

Pathogenic Organisms Bacteria

• can be treated by antibiotics– examples: • strep throat, abscesses, gonorrhea, syphilis,

chlamydia, Rocky Mountain Spotted Fever, Lyme disease

• vaccinations can prevent some bacterial infections – example:• pneumonia

Pathogenic Organisms Fungi

• molds and yeast– multicellular or unicellular organisms, more

complex than bacteria

Pathogenic Organisms Fungi

• Examples: – athletes foot,

ringworm, vaginal yeast infection, thrush

Pilobolus, a fungus

Pathogenic Organisms Protozoa

• largest single celled organism• relatively few cause disease in humans• many parasites passed by insects• transmitted by food

Pathogenic Organisms Protozoa

• Examples: – malaria, dysentery,

sleeping sickness

Amoeba, a protozoan

Pathogenic OrganismsClostridium difficile

(C. difficile)

• C. difficile is: – a pathogenic species of anaerobic bacteria

causing pseudomembranous colitis and diarrhea, after receiving antibiotic therapy. This is frequent cause of nosocomial diarrhea

Definitions

• Anaerobic – a microorganism that grows and lives in the

complete or almost complete absence of oxygen

• Pseudomembranous colitis– diarrhea caused by overuse of antibiotics

transmitted by healthcare workers not washing hands properly

Pathogenic Organisms C. difficile

– common hazard of antibiotic use– most common cause of nosocomial infectious

diarrhea– may cause bleeding & bowel perforation– can exist months on environmental surfaces &

flourishes on hands of healthcare workers– At risk patients: • chemotherapy, antibiotic therapy &

gastrointestinal procedures

C. difficile

• Standards of care for patient w/ diagnosis of C. difficile– good handwashing before & after patient care

procedures– use of Standard Precaution barriers for Contact

Isolation guidelines (gown, gloves, private room)– the antibiotic related to the cause of C. difficile

will be discontinued by physician and further care will begin

Pathogenic OrganismsVancomycin Resistant Enterococcus (VRE)

• VRE is: – a bacteria that normally lives in the digestive

tract that has developed a resistance to the antibiotic vancomycin and most other antibiotics

Definitions

• Vancomycin – antibiotic used to treat strep and staph

infections• Enterococcus – any Streptococcus that inhabits the intestinal

tract

Pathogenic Organisms VRE

– caused by overuse of antibiotics– VRE infections frequently found in:

• urinary tract, at surgical sites, and in the bloodstream– spreads through:

• direct contact with a VRE infected patient• direct contact with surfaces & equipment

contaminated with VRE • hands of a healthcare worker contaminated with VRE

– lives weeks on surfaces

VRE

• At risk patients for VRE:– immunosuppressed conditions– history of vancomycin therapy– indwelling urinary or central venous catheters– elderly– abdominal surgery patients– wounds/burn victims

VRE

• Standards of Care for VRE diagnosed patients:– good handwashing before & after care– use Standard Precaution barriers and contact

Isolation Precautions – the antibiotic will be discontinued by a

physician with plan for further care

Pathogenic Organisms (MRSA)

• Methicillin Resistant Staphylococcus Aureus (MRSA) is:– bacteria that populates the skin, mucous

membranes and upper respiratory tract, the intestines and genitourinary tracts that has become resistant to the antibiotics methicillin and penicillin

Pathogenic Organisms MRSA

– endemic (expected “normal” incidence) within community & tertiary hospitals, skilled-nursing facilities & long-term care

– most frequent sites of this bacteria is the nares, groin, axilla and gut

– transmitted primarily on the hands of the healthcare workers

MRSA

• At risk patients for MRSA:– those on broad-spectrum antibiotics therapy– immunosuppressed patients– burn patients– central venous catheters– surgical wounds– prolonged hospital stays

MRSA

• Standard of care for patient w/MRSA diagnosis:– topical ointment to nostrils– if infected, vancomycin

Key FactorsC. difficile, VRE, MRSA

– handwashing & standard precautions– single room for infected/colonized patients– use antiseptic cleansers in high risk areas – daily cleansing of environmental surfaces that

have had direct hand contact

Key FactorsC. difficile, VRE, MRSA

– dedicate equipment for exclusive use for infected patient(stethoscopes, BP cuffs, etc.)

– keep equipment off bed & bed tables– provide protective gear to patient when

leaving their room (mask, gown, etc.)

Infection Cycle

• Three Elements Required:– source of infecting

microorganisms– susceptible host– mode of transmission

source

susceptible host

mode oftransmission

Infection Cycle

• Source– may include persons with acute disease– persons in the incubation period of disease– persons who are colonized by infectious agent– persons who are chronic carriers– can be inanimate objects

Infection Cycle

• Host– one infected with a pathologic microorganism– resistance varies– may develop immunity– may be an asymptomatic carrier– may develop clinical disease

Infection CycleTransmission

• May be transmitted by more than one route

• Five main routes:– contact-direct or indirect– droplet– airborne– common vehicle– vectorborne

1. Contact Transmission

• *most frequent mode of noscomial infection• Direct Contact – skin to skin

• Indirect Contact – contact with an inanimate object contaminated

by the infected patient

2. Droplet Transmission

– a form of contact transmission

– droplets are propelled a short distance (3 feet)

– droplets are deposited on hosts such as the mucous membranes of eye, nose or mouth

droplets are generated bycoughing, sneezing or talking

2. Droplet Transmission

– droplets transmitted during medical procedures of bronchoscopy or suctioning that put healthcare workers at risk

– private room ideal• Can be placed w/other similar conditions 3’ apart

if room availability is an issue– healthcare worker must wear mask when

caring for a person with droplet isolation precautions

– Example: • Influenza

3. Airborne Transmission

– spreads by way of airborne droplets or dust particles containing infectious agents (microorganisms) and inhaled by the new host

– spread by air currents– special handling and ventilation required to prevent

transmission– requires private room – Examples

• tuberculosis, rubeola, and varicella (chicken pox), herpes zosters viruses spread via airborne transmission

3. Airborne Transmission

– spreads by way of airborne droplets or dust particles containing infectious agents

– spread by air currents– special handling and ventilation required to

prevent transmission– requires private room – Examples

• tuberculosis, rubeola, and varicella (chicken pox), herpes zosters viruses spread via airborne transmission

4. CommonVehicle Transmission

– microorganisms transported by contaminated food, water, medication or equipment

– Examples: • Hepatitis A, salmonella, Typhoid Fever

5. Vectorborne Transmission

– vectors transport disease• mosquitoes, flies, ticks,

rats and other vermin transmit disease

– Examples: • rabies, malaria, Rocky

Mountain FeverTick

How Microorganisms Grow in Humans

• Need:– food– oxygen

• aerobes-need oxygen• anaerobes-do not need oxygen

– temperature• 98.6 F or 36 C or warmer

– moisture– pH

• acidity or alkalinity

Natural Defenses of the Host

• Hairs– cilia

• Fluid– tears, ear wax, blood

• Skin Tissue– intact and healthy

• Proper Rest• Proper Nutrition

• Natural Immunity– childbirth & disease

process

• Phagocytosis– cells that can destroy

bacteria

• Normal flora– bacteria present that do

not normally cause disease

– streptococci

Predisposing Factors for Disease

• Poor nutrition• Fatigue• Poor health habits• Pre-existing illness• Gender• Genetics• Climate/Weather• Occupational

• Age– very young– very old

• Medical treatment– chemotherapy,

radiation therapy, bone morrow transplants, immuno-suppressed conditions, indwelling catheters

Knowledge Assessment

• 1. Give the definition for microorganism.• 2. List two examples of virus, bacteria, and fungi.• 3. List the 3 required elements of the infection cycle.• 4. Compare and contrast contact, droplet, and

airborne transmission of microorganisms.• 5. List five natural defenses of the body.