infection and its mode of transmission

8/19/2019 Infection and Its Mode of Transmission

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INTRODUCTION TO

INFECTION


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INFECTION

1. DEFINITION

2. CAUSES – MODES OF DISEASETRANSMISSION

3. CHAIN OF INFECTION

4. PROCESS BREAKAGE

5. PREVENTION

6. UNIVERSAL PRECAUTIONS


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Infection is the

lodgement andmultiplication of

organism in the

tissue of host

Biofilms of the different

types of bacteria

Microcolonies


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INFECTIOUS DISEASE

Any microorganism that can cause a disease suchas a bacterium, virus, parasite, or fungus. Reasons

that the organism will cause an infection are

virulence (ability to multiply and grow),

invasiveness (ability to enter tissue), andpathogenicity (ability to cause disease).


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TYPES OF INFECTIOUS AGENTS

BACTERIA

FUNGI

PROTOZOA

RICKETTSIA VIRUSES


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NATURE OF MICROORGANISMS

Microorganisms (microbes) are

small, living organisms that are

not visible to the naked eye.Pathogens (germs) are

microorganisms that cause

disease.


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NATURE OF MICROORGANISMS

At times, a microorganism that is beneficial in

one body system can become pathogenic when

it is present in another body system.Escherichia coli (E. coli) bacteria:

Large intestine: beneficial, part of the

natural flora.

Urinary system: causes an infection.


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TYPES OF MICROORGANISMS

BacteriaSimple, one-celled

microorganisms that areclassified according totheir shape andarrangement.

Cause diseases such asstrep throat, pneumonia,meningitis andtuberculosis.


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TYPES OF MICROORGANISMSFungi A plantlike organism thatlives on dead organic matter.

Yeasts and molds can bepathogenic.

Cause conditions such asringworm, athlete’s foot,yeast infections, and thrush.

Antifungal medications Usedto treat patient.


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ProtozoaOne-celled animal like organisms

often found in decayed materialsand contaminated water.Many contain flagella which allow

them to move freely.Cause diseases such as malaria,

trichomonas, and amebic dysentery.


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Rickettsiae

Parasites that live inside the cells of

other living organisms.

Commonly found in fleas, lice, ticks, and

mites and are transmitted to humans by

the bites of these insects.

Cause diseases such as Rocky Mountainspotted fever and typhus fever.

Antibiotics are effective against many

diseases.


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Viruses

Smallest of all microorganisms – visible onlyusing an electron microscope.

Cannot reproduce unless they are insideanother living cell.Spread by contact with blood and otherbody fluids.

Difficult to destroy. Not affected byantibiotics.

Associated with diseases such as thecommon cold, chicken pox, herpes, hepatitisB, measles, warts, polio, influenza, and

AIDS.


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VIRUSES

Three viruses are of major concern to the

health care worker:Hepatitis B – leads to destruction and scarring of

liver cells. Vaccine is available.

Hepatitis C – also causes serious liver damage. No

vaccine. Often misdiagnosed as the flu.

AIDS/HIV – suppresses the immune system. No

cure and no vaccine.


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FACTORS THAT

INFLUENCE MICROBIALGROWTHFollowing factors influence microbial growth:

TemperaturepH, or the values used in chemistry to express thedegrees of acidity or alkalinity of a substance

DarknessFoodMoistureOxygen


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FACTORS THAT

INFLUENCE MICROBIALGROWTH Aerobic microbes – live only

in the presence of oxygen.

Anaerobic microbes – grow

best in the absence of oxygen.


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CAUSING AN INFECTION

Pathogenic microorganisms cause infection

and disease in different ways.Produce poisons (toxins) which harm the body. Ex:

Tetanus.

Allergic reaction in the body causing runny nose,

watery eyes, sneezing.

Attack and destroy the living cells they invade. Ex:

Malaria (rbc’s).


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CLASSIFICATION OF INFECTION

Endogenous – disease originates within thebody. Ex: metabolic disorders, congenitalabnormalities, tumors.

Exogenous – disease originates outside thebody. Ex: chemical agents, electricalshock, trauma.

Nosocomial – acquired by an individual in

a health care facility (workers to patient).Many are antibiotic resistant, life-threatening.

Opportunistic – occur when the body’sdefenses are weak. Ex: pneumonia w/AIDs.


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Focal infection: It is a condition where due to

infection at localized sites like appendix and

tonsil, general effects are produced.

Cross infection: When a patient suffering from a

disease and new infection it set up from

another host or external source

CLASSIFICATION OF INFECTION


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STAGES OF INFECTIOUS DISEASE

Incubation period – no symptoms. Prodromal period – mild and

generalized symptoms (fever,

weakness, headache). Invasive stage – symptoms specific to

the disease.

Decline stage – symptoms subside.Convalescence – no symptoms,

health returns to normal.


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CHAIN OF INFECTION

For an infection to develop,

each link of the chainmust be connected.

Breaking any link of the chain

can stop the transmissionof infection!


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CHAIN OF INFECTION

Chain of

infection

contains six

elements. If

broken,

infection will

not occur.


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CHAIN OF INFECTION

Infectious Agent – pathogen such as

a bacteria or virus.

Reservoir – a place the pathogen

can live.Examples: human body, animals, the

environment, fomites.

Fomites are objects contaminated with

infectious material that contains

pathogens.Ex: doorknobs, bedpans, linens, instruments.


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CHAIN OF INFECTION

Portal of Entry – way to enter the new

reservoir or host.Respiratory tract, mucous membranes, and

gastrointestinal tract are common.Damaged skin.


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CHAIN OF INFECTION

Susceptible Host – one that is capable of being

infected.Microorganisms must be present in large enough

quantity to be virulent.The host must be susceptible.Individuals with an immunity to certain pathogens

will not be susceptible.


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CHAIN OF INFECTION

Mode of Transmission – way inwhich it can be transmitted toanother reservoir or host where it

can live.Can be through direct contact or airborne droplet.Contaminated hands are one of the most commonsources of direct transmissions.

Hand washing is one of the mosteffective means of preventing the spreadof pathogens.


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CHAIN OF INFECTION

Portal of Exit – way to escape from thereservoir in which it has beengrowing.UrineFecesSalivaRespiratory tract

SkinBloodGastrointestinal tractMucous dischargeTears


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BODY DEFENSESIf defense mechanisms are intact and theimmune system is functioning, a humancan frequently fight off the causative agentand not contract the disease.Mucous membranes (traps pathogens)Cilia (propel pathogens out of respiratory tract)Coughing and sneezingHydrochloric acid (stomach)Tears in the eyes(contain bacteriocidal chemicals)FeverInflammation (wbc’s destroy pathogens)Immune response (produce antibodies)


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SIGNS & SYMPTOMS OF

INFECTION Redness Swelling Tenderness Warmth

Drainage Red streaks leading awayfrom wound


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BREAKAGE OF CHAIN OF

INFECTION

There are various methods of breaking the chain

of infection to reduce harm to patient and

prevent disease


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THANK YOU

infection and its mode of transmission

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