CHAPTER 4

MICROBIOLOGY

OBJECTIVESWith successful completion of this chapter,

students will be able to:1. Define the term microbiology2. State the facts about various microbes;

bacteria virus and fungi 3. Identify and classify bacteria according to its

shape, color change and need for oxygen.3. Describe transmission of microorganisms and

discuss chain of infection.4. Review basic procedures of infection control

and discuss the important role of CS technician in controlling infection.

MICROBIOLOGY• The study of microorganisms. The science which treats the nature, life and action of microorganisms.• Central Service Department protects patients from harmful microorganisms.

• CS Tech• Must understand basic microbiological principles to provide that protection.

INFECTION CONTROL

Primary function of Central Service Department is :

Infection control• Patient Safety• Protect patients from infection

WORKER SAFETY• Central Service Technicians must also have a basic understanding of microbiology to protect themselves from pathogens that may be present during their routine duties.

INFECTION CONTROL

SERVICES INCLUDE• Cleaning

• Disinfection

• Sterilization

• Sterility Maintenance

IT IS IMPOSSIBLE TO SEE MICROORGANISMS WITHOUT A

MICROSCOPE

MUST LEARN TO SEE MICROORGANISMS WITH

THEIR “MIND’S EYE”

CENTRAL SERVICE TECHNICIANS

LOOKING THROUGH A MICROSCOPE

• A magnified picture of a contaminated needle illustrates what the naked eye cannot see.

• Microorganisms can pose a threat to both patients and employees.

TOR INFECTED BY CONTACT WITH INFECTIOUS ORGANISMS OR OTHER

MATERIAL.

CONTAMINATION

TO EFFECTIVELY CONTROL MICROORGANISMS, CS TECHNICIANS

MUST UNDERSTAND• Basic facts about microorganisms

• How microorganisms are identified and classified

• How they grow

• What conditions they need to grow and reproduce

• How they are transmitted from person-to-person and place-to-place

• How they can be controlled and killed

BASIC FACTS ABOUT MICROORGANISMS

NOT ALL MICROORGANISMS ARE HARMFUL

• Microorganisms are necessary for our existence.• Microorganisms help with:• Food Development• Decay of Leaves and

other natural waste• Sewage Treatment• And more.

SIZE AND STRUCTURE OF BACTERIA

•Most bacterial cells are 1-2 microns in size.

• A micron is 1/25,000 of an inch.

Cell Wall the structure that

surrounds the cell and helps it maintain

its shape.

Cell Membrane Allows some liquids and gasses

to seep in and out of the cell.

Cytoplasm -a generally clear jelly like

material that fills the cell. The cell's chemical reactions and

protein syntheses are carried out in the cytoplasm.

Nucleus the controlling unit of the cell.

It regulates growth, the use of food, and the production of new

cell components.

Flagella- thread like "tails" attached

to the cell that enable it to move through liquid.

Capsule A mucous material

that surrounds the wall of some cells and provides

protection.

A MICROORGANISM CAPABLE OF FORMING A THICK WALL AROUND

ITSELF THAT ENABLES IT TO SURVIVE IN ADVERSE CONDITIONS; A RESISTANT FORM OF BACTERIA

*BACTERIAL SPORES POSE SPECIFIC CHALLENGES TO CS TECHNICIANS

SPORE

COMMON WAY TO IDENTIFY AND CLASSIFY MICROORGANISMS INCLUDE

• Bacteria are often classified by their:• Shape• Color Change•Need for Oxygen

CLASSIFICATION BY SHAPE

• Bacteria are divided into 3 main groups by shape:• Cocci are round or spherical shaped and

occur in pairs, clusters, or chains.

• Rods (bacilli) may be large and brick-shaped or small and stick-like.

• Spirals vary from comma-shaped to longer bacteria with many twists.

SHAPES• COCCI (round)

i.e.: Staphylococc

us Aureus

• BACILLUS (rods)i.e.:

Pseudomonas

Aeruginosa

• SPIRILLUM (Spirals)

i.e.: Helicobact

erPyroli

BACTERIA ARE CLASSIFIED BY COLOR CHANGE

• Bacteria are normally clear, color change occurs when bacteria are subjected to certain tests (stains).

• Common Stain Tests• Gram Stain• Ziehl-Neilson Stain

THE GRAM STAIN

• In 1884, Hans Christian Gram, a Danish doctor working in Berlin, developed a process to divide bacteria into two groups.

GRAM STAIN PROCEDURE

• The Gram stain is the most commonly used differential stain for determining cell morphology. Differential stains allow for distinguishing certain characteristics of cells, and the stains commonly use two or more stains. The Gram stain, which divides most clinically significant bacteria into two main groups, is the first step in bacterial identification.

• The Gram stain process:• 1. crystal violet, the primary stain: followed by

iodine, which acts as a mordant by forming a crystal violet-iodine complex, then alcohol, which decolorizes, followed by safranin, the counterstain.

• G+ organisms are purple • G- organisms are red

BACTERIA ARE CLASSIFIED BY THEIR NEED FOR OXYGEN

• Aerobic Bacteria – Capable of growing in the presence of free oxygen. Requires Oxygen.

• Anaerobic Bacteria – Capable of growing in the absence of free oxygen. Does not Require Oxygen.

NEED THE RIGHT CONDITIONS TO GROW.BACTERIA

TEMPERATURE REQUIREMENTS FOR BACTERIA

Name Description Optimum Growth Temperatures

Psychrophiles Likes Cold Temperatures

59o F to 68o F (15o C to 20o C)

Mesophiles* Likes Moderate Temperatures

68o F to 113o F (20o C to 45o C)

Thermophiles Likes Warm Temperatures

122o F to 158o F (50o C to 70o C)

*Mesophiles are often pathogenic to humans and grow well at body

temperature.

BACTERIAL REPRODUCTION

• Bacteria reproduce by dividing.

• This occurs approximately every 20 minutes.

• This process is called Binary Fission.

• This illustration above shows how E. coli reproduces.

SOME MICROORGANISMS ADAPT AND CHANGE TO INCREASE THEIR CHANCES OF SURVIVAL

RESISTANT MICROORGANISMS

MRSA USUALLY OCCURS IN PATIENTS WHO HAVE BEEN ON ANTIBIOTIC THERAPY FOR A

LONG TIME

METHICILLIN-RESISTANT STAPHYLOCCUS AUREUS (MRSA)

Staphyloccus aureus bacteria that have developed a resistance to Methicillin, the

drug of choice

ENTEROCOCCUS BACTERIA THAT ARE NO LONGER SENSITIVE TO VANCOMYCIN

TRANSMISSION CAN OCCUR BY DIRECT CONTACT, OR INDIRECTLY VIA THE HANDS OF PERSONNEL

VANCOMYCIN-RESISTANT ENTEROCOCCUS (VRE)

VIRUSES, PROTOZOA, AND FUNGI

NON-BACTERIAL ORGANISMS

ONE OF A GROUP OF MINUTE INFECTIOUS AGENTS THAT ONLY

GROW IN LIVING TISSUE OR CELLS

VIRUS

VIRUSES ARE TINY• Viruses are about 1000

times smaller than bacteria.

• If you were to enlarge a virus to the size of a baseball, the average bacterium would be the side of a pitcher’s mound, and one single cell from the human body would be the size of the entire ballpark. (www.Mayoclinic.com)

COMMON VIRAL DISEASES

• Smallpox• Rabies• Yellow Fever• Influenza• Measles• Acquired Immune Deficiency Syndrome (AIDS)

• Mumps• Polio• Common Colds• Shingles• Cold Sores• Warts• Hepatitis

HEPATITIS• Five distinct viruses,

A, B, C, D, and E.

• A is often implicated in foodborne illnesses.

• B, C, D, and E are transmitted in body fluids.

• There are vaccines available for A & B.

• Hepatitis B Vaccine is strongly recommended for Central Service Technicians.

HSV & HIV

• Recurrent skin and mucous membrane infections.

• HSV Type 1 is associated with cold sores and fever blisters.

• HSV Type 2 is associated with genital infections.

• Human Immunodeficiency Virus (HIV)• Causes AIDS

• Occurs when the virus enters the blood stream.

ANY ONE-CELLED ANIMAL-LIKE MICROORGANISM IN THE SUB-

KINGDOM OF PROTOZOA

PROTOZOAN

FUNGI

• Plant-like organism group that includes molds, mushrooms, and yeasts without chlorophyll

• They live by feeding off living or dead organisms

• Fungi are involved in the production of most kinds of antibiotics

• Several species of fungi can cause respiratory disease in humans who inhale spores through dust, bird droppings, soil and other sources

SUPERFICIAL FUNGI

• Attack mainly epidermis, hair, nails, and mucosal surfaces.

• For example, Ringworm and Athlete’s Foot.

TRANSMISSION OF MICROORGANISMS

• Microorganisms cannot move by themselves, but they have been called the World’s Greatest Hitchhikers.

• Microorganisms can be transmitted by air currents, dust particles, in liquids, on solid objects like instruments and equipment…and by humans (us).

FACTS ABOUT MICROORGANISMS

• We come in contact with thousands of types of microorganisms each day.

• Only about 1% are harmful to humans.

• However, any microorganism can be harmful to patients whose defenses are compromised due to illness, injury or invasive procedure.

DISEASE-PRODUCINGCENTRAL SERVICE TECHNICIANS PROTECT PATIENTS

FROM PATHOGENIC ORGANISMS

PATHOGENIC

FOR OUR PATIENTS

•The hospital is a very dangerous place.

OUR JOB IS TO PROTECT THEM!

BREAKING THE CHAIN OF INFECTION

• The infectious disease process is a complex relationship between the source, the host, and the environment.

• Central Service Technicians can protect patients from infection by disrupting that process.

THE CHAIN OF INFECTIONCausative

Agent

Reservoir of the Agent

Portal of ExitOf the Agent

from the Reservoir

Mode of Transmission

Portal of EntryInto the Host

Susceptible Host

CAUSATIVE AGENT

• The microorganism that causes an infectious disease.

• Characteristics that make microorganisms capable of causing disease:• Invasiveness• Pathogenicity• Virulence• Infectious Dose• Viability in a free state.• Ability to develop resistance to antimicrobial

agents.

BREAK THE CHAIN OF INFECTION BY:

• Eliminating the Causative Agent.

• That can be accomplished by:• Avoiding cross-contamination.• Thorough Cleaning• Disinfection• Sterilization

THE PLACE WHERE AN INFECTIOUS AGENT CAN

SURVIVE

RESERVOIR OF THE AGENT

BREAK THE CHAIN OF INFECTION BY:

• Reducing Reservoirs

• Central Service Technicians can Reduce Reservoirs by:• Practicing Good Personal Hygiene and Health Habits• Properly cleaning, disinfecting, and sterilizing equipment, instruments, and utensils

THE PATH BY WHICH AN INFECTIOUS AGENT LEAVES

THE RESERVOIR

PORTAL OF EXIT

PORTALS OF EXIT• Respiratory Tract - Through sneezing and coughing.

• Genitourinary Tract – Through urine, vaginal secretions, and semen.

• Gastrointestinal Tract – Through vomit or stools.• Skin/Mucous Membrane – Through mucous or wound

drainage.

• Blood – Through Blood transfusions or contact with blood.

• Transplacental – Through the placenta from mother to baby.

BREAK THE CHAIN OF INFECTION BY:

• Protecting yourself and others from exposure.

• Central Service Technicians should:• Practice proper waste disposal• Wear appropriate Personnel Protective Equipment (PPE) when they may come in contact with infectious substances.

THE METHOD OF TRANSFER OF AN INFECTIOUS AGENT FROM THE

RESERVOIR TO A SUSCEPTIBLE HOST

MODE OF TRANSMISSION

MODES OF TRANSMISSION

• Contact – Direct contact from person-to-person or droplet contact from coughing or sneezing

• Common Vehicle – Occurs when infectious agents are present in a vehicle such as food, blood, or water

• Airborne – Infectious agents found in tiny droplet nuclei or dust that are suspended in the air and may travel. For example, through a ventilation system

• Vector-borne – carried by insects (rare in U.S. Hospitals)

BREAK THE CHAIN OF INFECTION BY:

• Central Service Technicians can disrupt the Mode of Bacterial Transmission by:• Maintaining good hand hygiene• Following good work practices for cleaning, decontamination, disinfection and sterilization.• Following airflow control guidelines.• Following Standard Precautions guidelines.

THE PATH USED BY AN INFECTIOUS AGENT TO ENTER A

SUSCEPTIBLE HOST

PORTAL OF ENTRY

PORTALS OF ENTRY

• Respiratory Tract• Genitourinary Tract• Gastrointestinal Tract• Skin/Mucous Membranes• Transplacental• Parenteral

BREAK THE CHAIN OF INFECTION BY:

• Central Service Technicians can disrupt the Chain of Infection by:• Ensuring that equipment, utensils and instruments are properly cleaned, disinfected, and/or sterilized.• Following Standard Precautions when handling contaminated items.

A PERSON OR ANIMAL THAT LACKS THE ABILITY TO RESIST INFECTION

BY AN INFECTIOUS AGENT

SUSCEPTIBLE HOST

HOST SUSCEPTIBILITY IS AFFECTED BY:

• Age

• Disease

• Nutritional status

• Compromised immune status

• Trauma

THE CHAIN OF INFECTION**(FROM A CS PERSPECTIVE)

Bacteria

Surgical Instrument

InstrumentInadequately

SterilizedBetween Patients

Patient # 1

InstrumentIntroduced

IntoPatient # 2

Patient # 2Infected

WHAT WE CAN’T SEE CAN HURT US!

•Millions of tiny bacteria, too small to see, inhabit our work area.

UNDERSTANDING MICROORGANISMS HELPS

CENTRAL SERVICE TECHNICIANS:

• Prevent them from Reproducing

• Control their Transmission

• Destroy them.

• Protect Patients, employees and ourselves.

PREPAREDNESS

• Understanding the basics about microorganisms is the first step in being prepared to fight them.