1. CHAPTER 4
MICROBIOLOGY

2. OBJECTIVES
With successful completion of this chapter, students will
be able to:
1. Define the term microbiology
2. 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.

3. 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.

4. INFECTION CONTROL
Primary function of Central Service
Department is :
Infection control
• Patient Safety
• Protect patients from infection

5. 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.

6. INFECTION CONTROL
SERVICES INCLUDE
• Cleaning
• Disinfection
• Sterilization
• Sterility
Maintenance

7. IT IS IMPOSSIBLE TO SEE MICROORGANISMS
WITHOUT A MICROSCOPE

8. MUST LEARN TO SEE
MICROORGANISMS WITH
THEIR “MIND’S EYE”
CENTRAL SERVICE
TECHNICIANS

9. 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.

10. TOR INFECTED BY CONTACT WITH INFECTIOUS
ORGANISMS OR OTHER MATERIAL.
CONTAMINATION

11. 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

12. BASIC FACTS ABOUT MICROORGANISMS

13. 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.

14. SIZE AND STRUCTURE OF
BACTERIA
• Most bacterial
cells are 1-2
microns in size.
• A micron is
1/25,000 of an
inch.

16. 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

17. COMMON WAY TO IDENTIFY AND
CLASSIFY MICROORGANISMS INCLUDE
• Bacteria are often classified by their:
• Shape
• Color Change
• Need for Oxygen

18. 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.

19. SHAPES
• COCCI
(round)
i.e.:
Staphylococcu
s Aureus
• BACILLUS
(rods)
i.e.:
Pseudomona
s Aeruginosa
• SPIRILLUM
(Spirals)
i.e.:
Helicobacte
rPyroli

20. 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

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

22. 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

23. 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.

24. NEED THE RIGHT CONDITIONS TO GROW.
BACTERIA

25. 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.

26. 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.

27. SOME MICROORGANISMS ADAPT AND CHANGE TO INCREASE THEIR
CHANCES OF SURVIVAL
RESISTANT
MICROORGANISMS

28. 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

29. 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)

30. VIRUSES, PROTOZOA, AND FUNGI
NON-BACTERIAL
ORGANISMS

31. ONE OF A GROUP OF MINUTE INFECTIOUS
AGENTS THAT ONLY GROW IN LIVING TISSUE
OR CELLS
VIRUS

32. 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)

33. COMMON VIRAL DISEASES
• Smallpox
• Rabies
• Yellow Fever
• Influenza
• Measles
• Acquired Immune
Deficiency
Syndrome (AIDS)
• Mumps
• Polio
• Common Colds
• Shingles
• Cold Sores
• Warts
• Hepatitis

34. 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.

35. 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.

36. ANY ONE-CELLED ANIMAL-LIKE
MICROORGANISM IN THE SUB-
KINGDOM OF PROTOZOA
PROTOZOAN

37. 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

38. SUPERFICIAL FUNGI
• Attack mainly
epidermis, hair, nails,
and mucosal surfaces.
• For example, Ringworm
and Athlete’s Foot.

39. 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).

40. 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.

41. DISEASE-PRODUCING
CENTRAL SERVICE TECHNICIANS PROTECT PATIENTS FROM
PATHOGENIC ORGANISMS
PATHOGENIC

42. FOR OUR PATIENTS
•The hospital
is a very
dangerous
place.

43. OUR JOB IS TO PROTECT
THEM!

44. 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.

45. THE CHAIN OF INFECTION
Causative
Agent
Reservoir
of the
Agent
Portal of Exit
Of the Agent
from the
Reservoir
Mode of
Transmission
Portal of Entry
Into the Host
Susceptible
Host

46. 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.

47. BREAK THE CHAIN OF INFECTION BY:
• Eliminating the Causative Agent.
• That can be accomplished by:
• Avoiding cross-contamination.
• Thorough Cleaning
• Disinfection
• Sterilization

48. THE PLACE WHERE AN INFECTIOUS
AGENT CAN SURVIVE
RESERVOIR OF THE AGENT

49. 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

50. THE PATH BY WHICH AN INFECTIOUS
AGENT LEAVES THE RESERVOIR
PORTAL OF EXIT

51. 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.

52. 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.

53. THE METHOD OF TRANSFER OF AN
INFECTIOUS AGENT FROM THE RESERVOIR TO
A SUSCEPTIBLE HOST
MODE OF TRANSMISSION

54. 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)

55. 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.

56. THE PATH USED BY AN INFECTIOUS
AGENT TO ENTER A SUSCEPTIBLE HOST
PORTAL OF ENTRY

57. PORTALS OF ENTRY
• Respiratory Tract
• Genitourinary Tract
• Gastrointestinal Tract
• Skin/Mucous Membranes
• Transplacental
• Parenteral

58. 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.

59. A PERSON OR ANIMAL THAT LACKS THE
ABILITY TO RESIST INFECTION BY AN
INFECTIOUS AGENT
SUSCEPTIBLE HOST

60. HOST SUSCEPTIBILITY IS
AFFECTED BY:
• Age
• Disease
• Nutritional status
• Compromised immune
status
• Trauma

61. THE CHAIN OF INFECTION*
*(FROM A CS PERSPECTIVE)
Bacteria
Surgical
Instrument
Instrument
Inadequately
Sterilized
Between
Patients
Patient # 1
Instrument
Introduced
Into
Patient # 2
Patient # 2
Infected

62. WHAT WE CAN’T SEE CAN HURT US!
•Millions of tiny
bacteria, too
small to see,
inhabit our
work area.

63. UNDERSTANDING
MICROORGANISMS HELPS CENTRAL
SERVICE TECHNICIANS:
• Prevent them from Reproducing
• Control their Transmission
• Destroy them.
• Protect Patients, employees and ourselves.

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