Introduction-Microbiology-sciencesss.ppt

life science of invisible world

1. © 2009 The McGraw-Hill Companies, Inc. All rights reserved
Introduction to MicrobiologyIntroduction to Microbiology
PowerPoint® presentation to accompany:
Medical Assisting
Third Edition
Booth, Whicker, Wyman, Pugh, Thompson

2. 46-2
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Learning Outcomes
46.1 Define microbiology.
46.2 Describe how microorganisms cause disease.
46.3 Describe how microorganisms are classified and
named.
46.4 Explain how viruses, bacteria, protozoans, fungi,
and parasites differ and give examples of each.

3. 46-3
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Learning Outcomes (cont.)
46.5 Describe the process involved in diagnosing an
infection.
46.6 List general guidelines for obtaining specimens.
46.7 Describe how throat culture, urine, sputum, wound,
and stool specimens are obtained.
46.8 Explain how to transport specimens to outside
laboratories.

4. 46-4
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Learning Outcomes (cont.)
46.9 Describe two techniques used in the direct
examination of culture specimens.
46.10 Explain how to prepare and examine stained
specimens.
46.11 Describe how to culture specimens in the medical
office.

5. 46-5
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Learning Outcomes (cont.)
46.12 Explain how cultures are interpreted.
46.13 Describe how to perform an antimicrobial
sensitivity determination.
46.14 Explain how to implement quality control
measures in the microbiology laboratory.

6. 46-6
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Introduction
Microorganisms
cause disease or
infection
Pathogenic in nature
Displaced from their
natural environment
Medical assistant
Identification of
microorganisms
Proper collection
techniques
Testing procedures
Quality control

7. 46-7
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Microbiology and the Role of the
Medical Assistant
Microbiology – study of microorganisms
(simple forms of life visible only with a
microscope)
Microorganisms
Normal flora
Pathogenic

8. 46-8
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Medical assistant
Assists physician
Obtains specimens
Prepares specimens for direct examination
Prepares specimens for transportation to
reference laboratory
If office has a POL, performs microbiologic
procedures
Microbiology and the Role of the
Medical Assistant (cont.)

9. 46-9
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How Microorganisms Cause Disease
Cause disease in variety of ways
Use nutrients needed by cells and tissues
Damage cells directly
Produce toxins
May remain localized or become systemic
Transmission
Direct contact
Indirect contact

10. 46-10
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How Microorganisms Cause
Disease (cont.)
Localized
symptoms
Swelling
Pain
Warmth
Redness
Generalized symptoms
Fever
Tiredness
Aches
Weakness
Normal flora
Provides a barrier
Can cause an infection

11. 46-11
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your Knowledge
1.What role does the medical assistant play in relation to
microbiology?
ANSWER: The medical assistant may assist the physician in
obtaining specimens, obtain specimens herself, prepare
specimens for direct examination or transport to a reference
laboratory, and possibly perform microbiologic procedures.
2.How do microorganisms cause disease?
ANSWER: Organisms cause disease by
using nutrients needed by cells and
tissues, damaging cells directly, or
producing toxins.

12. 46-12
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Classification and Naming of
Microorganisms
Classification by structure
Subcellular – DNA or RNA surrounded by a
protein coat – viruses
Prokaryotic – simple cell structure with no
nucleus or organelles – bacteria
Eukaryotic – complex cell structure with nucleus
and specialized organelles – protozoans, fungi,
parasites

13. 46-13
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Standardized naming
Genus
Category of biologic classification
Example – Staphylococcus
Species of organism
Represents a distinct type of microorganisms
Examples – Staphylococcus aureus and
Staphylococcus epidermidis
Classification and Naming of
Microorganisms (cont.)

14. 46-14
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Apply Your Knowledge
Describe the classifications of microorganisms and give
an example of each.
ANSWER: Microorganisms are classified as:
Subcellular organisms that have DNA or RNA surrounded
by a protein coat – viruses
Prokaryotic organisms have a simple cell structure with no
nucleus or organelles – bacteria
Eukaryotic have a complex cell structure with nucleus and
specialized organelles – protozoans, fungi, parasites

15. 46-15
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Viruses
Smallest known
infectious agents
Subcellular
microorganism
Have only nucleic acid
surrounded by a protein
coat
Must live and grow in
living cells of other
organisms
Hepatitis virus

16. 46-16
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Viruses (cont.)
Illnesses caused by viruses
Colds
Influenza
Croup
Hepatitis
Warts
Vaccines are available for many viruses
AIDS
Mumps
Rubella
Measles
Herpes

17. 46-17
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Bacteria
Single-celled prokaryotic organisms
Reproduce rapidly
Classification
Shape
Ability to retain dyes
Ability to grow
with / without air
Biochemical reactions
Bacillus bacterial
classification

18. 46-18
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Bacteria: Classification and
Identification
Shape
Coccus – spherical, round, or ovoid
Bacillus – rod-shaped
Spirillum – spiral-shaped
Virbrio – comma-shaped Spirillum bacterial
classification

19. 46-19
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Ability to retain certain dyes
Gram’s stain
Acid-fast stain
Ability to grow in presence or absence of air
Aerobes – grow best in the presence of oxygen
Anaerobes – grow best in the absence of oxygen
Biochemical reactions
Bacteria: Classification and
Identification (cont.)

20. 46-20
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Special groups
Mycobacteria – bacilli
with a cell wall that
differs from most bacteria
Rickettsiae
Very small
Live and grow within
other living organisms
such as mites and ticks
Chlamydiae
Cell wall structure
differs from other
bacteria
Live and grow within
other living cells
Mycoplasmas –
completely lack the
rigid cell wall
Bacteria: Classification and
Identification (cont.)

21. 46-21
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Protozoans
Single-celled eukaryotic organisms, larger than
bacteria
Found in soil and water
Illnesses
Malaria
Amebic dysentery
Trichomoniasis vaginitis
Leading cause of death in developing countries
Protozoan
Trichomonas
vaginalis

22. 46-22
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Fungi
Eukaryotic organisms
with rigid cell wall
Yeasts
Single-celled
Reproduce by budding
Molds
Large, fuzzy,
multicelled organisms
Produce spores
Superficial infections
Athlete’s foot
Ringworm
Thrush
Can cause systemic
infections
Yeast: a single-
celled fungi

23. 46-23
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Multicellular Parasites
Organisms that live on or in another organism and
use it for nourishment
Parasitic worms
Usually due to poor
sanitation
Roundworms
Flatworms
Tapeworms
Parasitic insects
Bite or burrow under
the skin
Mosquitoes
Ticks
Lice
mites

24. 46-24
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your Knowledge
Matching:
___ Yeast or mold A. Virus
___ Tapeworm / lice B. Bacteria
___ Classified by shape C. Protozoan
___ Subcellular organism D. Fungus
___ May be aerobic or anaerobicE. Multicellular parasite
___ Smallest known organism
___ Found in soil and water
E
ANSWER:
D
A
B
B
C
A
Very
Good!

25. 46-25
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How Infections Are Diagnosed
Steps to diagnosis and treatment
1.Examine the patient
Presumptive diagnosis
May or may not need additional tests
2.Obtain specimen(s)
Label properly
Include presumptive diagnosis

26. 46-26
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How Infections Are Diagnosed (cont.)
3.Examine specimen directly
Wet mount
Smear
4.Culture specimen
Culture medium – contains nutrients
Examine culture visually and microscopically

27. 46-27
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How Infections Are Diagnosed (cont.)
5.Determine sensitivity to
antibiotics
6.Treat the patient as
ordered
Antimicrobial – to kill
pathogen or suppress its
growth

28. 46-28
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your Knowledge
What is the process for diagnosing an infection?
ANSWER: There are six steps for diagnosis and treatment of
an infection:
1.Examine the patient 4. Culture the specimen
2.Obtain specimen(s) 5. Determine sensitivity
3.Examine specimen directly6. Treat patient / appropriate
antimicrobial
Super!

29. 46-29
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Specimen Collection
Must be collected correctly
If not, may not grow in
culture
Contaminants may be
mistakenly identified
Patient may receive
incorrect or harmful therapy

30. 46-30
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Specimen Collection (cont.)
Devices
Use appropriate collection
device or specimen container
Sterile swabs – absorbent
material on the tip
Collection and transporting systems
Sterile, self-contained
Transport medium
Aerobic or anaerobic

31. 46-31
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Specimen Collection: Guidelines
Avoid causing harm,
discomfort, or undue
embarrassment
Collect from
appropriate site
Obtain specimen at
correct time
Use appropriate
devices
Obtain sufficient
quantity of specimen
Obtain specimen prior
to the start of
antimicrobial therapy
Label correctly

32. 46-32
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Specimen Collection (cont.)
Throat culture specimens
Swab back of throat in the area
of the tonsils
Avoid touching any structures
in the mouth
Prepare culture plate or
prepare correctly for
transport to laboratory

33. 46-33
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Specimen Collection (cont.)
Urine specimen
Clean-catch
midstream to
minimize
contaminants
Process within 60
minutes or
refrigerate
Sputum specimen
Specimen from
lungs
Avoid
contaminating
specimen with
saliva

34. 46-34
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Specimen Collection (cont.)
Wound specimen
Swab wound or
lesion
Do not touch
outside of wound
Stool Specimens
Technique varies
Bacterial infection
Protozoal or
parasitic infection
Instruct patient in
correct collection
procedure

35. 46-35
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your Knowledge
What are the general guidelines for specimen collection?
ANSWER: They are to avoid causing harm, discomfort, or
undue embarrassment; collect from appropriate site; obtain
specimen at correct time; use appropriate collection devices;
obtain sufficient quantity of specimen; obtain specimen prior
to the start of antimicrobial therapy; and label specimen
correctly.

36. 46-36
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Transporting Specimens to an
Outside Laboratory
Many offices send cultures to an outside lab
Three main objectives
Follow proper collection
procedures and proper
collection device
Prevent deterioration of
specimen
Protect anyone handling
specimen

37. 46-37
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Transporting Specimens to an
Outside Laboratory (cont.)
Regularly scheduled daily
pickups by the lab
Most reliable
As-needed pickup by the lab
Through the mail
Follow U.S. Public Health Service
regulations
Etiologic Agent label

38. 46-38
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your Knowledge
What are the objectives for transporting a specimen to an
outside laboratory?
ANSWER: They are to follow proper collection procedures
and use proper collection device, prevent deterioration of the
specimen during transport, and protect anyone that will handle
specimen from exposure.
Impressive!

39. 46-39
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Direct Examination of Specimens
Enables physician to initiate treatment immediately
Wet mounts
NaCl mixed with
specimen of glass slide
Presence of pathogen
and movement of
microorganism
Potassium hydroxide
(KOH) mounts
Used if a fungal
infection of the skin,
nails, or hair is
suspected
KOH dissolves keratin
that can mask presence
of a fungus

40. 46-40
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Preparation and Examination of
Stained Specimens
Quick, tentative
diagnosis
Differentiation
between types of
infections
Gram’s stain
Moderate-
complexity test
Bacteria either
retain or lose purple
color
Gram-positive
bacteria
Gram-negative
bacteria

41. 46-41
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Culturing Specimens in the
Medical Office
More common to send
specimens for culture to
outside labs
Culturing involves placing a sample of
specimen on a culture medium
Medium – nutrients
Place in incubator for growth – colony develops
as microorganism multiplies

42. 46-42
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your Knowledge
1.What are the methods for preparing a slide for direct
examination by the physician?
ANSWER: They are wet mount and KOH mount.
2.How does the examination of stained specimens
facilitate patient care?
ANSWER: Stained specimens enable the physician
to provide a quick, tentative diagnosis and
differentiate between types of infections.

43. 46-43
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your Knowledge
3.What is the process for culturing a specimen?
ANSWER: The culture medium is inoculated with
the specimen and placed in an incubator to
promote growth of the organism on the culture
medium.

44. 46-44
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Culturing Specimens (cont.)
Culture media
Liquid, semisolid, or
solid forms
Contains agar
Selective or nonselective
Special culture units
Rapid urine culture – Uricult
Also available for throat, vaginal, and blood
specimens

45. 46-45
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Culturing Specimens (cont.)
Inoculating a culture plate
Transfer some of the specimen onto a culture
plate
Label the plate correctly
Qualitative analysis – determination of type of
pathogen
Quantitative analysis – number of bacteria
present in sample

46. 46-46
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Culturing Specimens (cont.)
Incubating culture plates
35 to 37
º
C for 24 to 78 hours
Agar side up
Interpreting cultures
Requires skill and practice
Characteristics of colonies
Relative number
Changes to media around colonies

47. 46-47
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Determining Antimicrobial Sensitivity
An outside lab
reports
Sensitive – no
growth
Intermediate – little
growth
Resistant –
overgrown
Procedure
Filter paper containing
antimicrobial agents
placed on inoculated
agar plate
Incubated for 24 hours
Evaluate effectiveness
of agent

48. 46-48
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your Knowledge
1.What is the difference between selective and
nonselective culture media?
ANSWER: Selective culture media allows the growth of only
certain kinds of bacteria. Unselective culture media support
the growth of most organisms.
2.The office received a culture sensitivity report on a
bacteria that said it was resistant to an antimicrobial.
What does this mean?
ANSWER: It means that the bacteria was not killed by the
antimicrobial and that there was an overgrowth of the bacteria.

49. 46-49
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Quality Control in the Medical Office
Ongoing evaluation
of the quality of
medical care being
provided
Objective means to
define, monitor, and
correct potential
problems
Routine evaluation
All media, staining
solutions, and
reagents
Equipment

50. 46-50
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Quality Control: Impact of CLIA ’88
Appropriate policies and procedures
Proper documentation
Lab policies and procedures
Materials
Personnel qualifications and training
Participation in proficiency testing program

51. 46-51
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Apply Your Knowledge
What is the purpose of a quality control program in the
medical office?
ANSWER: To provide an ongoing evaluation of the
quality of medical care provided and to provide an
objective means to define, monitor, and correct
potential problems.
Very Good!

52. 46-52
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
In Summary
Microorganisms are a major cause of disease
Medical assistant
Collects specimens
Processes or transports specimens
Quality control – ensures quality medical care

53. 46-53
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End of Chapter
Each organism's
environment,
for the most
part, consists of
other
organisms.
~ Kevin Kelly