1. Medical Assisting Chapter 46
PowerPoint® to accompany
Medical Assisting Chapter 46
Second Edition
Ramutkowski  Booth  Pugh  Thompson  Whicker
Chapter 46
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. Introduction to Microbiology
Objectives:
46-1 Define microbiology.
46-2 Describe how microorganisms cause diseases.
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.
46-5 Describe the process involved in diagnosing an infection.

3. Introduction to Microbiology
Objectives (cont.)
List general guidelines for obtaining specimens.
Describe how throat cultures, urine, sputum, wound, and stool specimens are obtained.
Explain how to transport specimens to outside laboratories.
46-9 Describe two techniques used in the direct examination of cultures specimens.
46-10 Explain how to prepare and examine stained specimens.

4. Introduction to Microbiology
Objectives (cont.)
46-11 Describe how to culture specimen in the medical office.
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.

5. Introduction You will learn:
Processes in identifying microorganisms
Culture medias used
Antimicrobial testing
Quality control
When microorganisms are pathogenic in nature or displaced from their natural environment, they cause infections and disease.
You must understand different life forms of microorganisms, how they may be identified, and how to teach proper collection techniques for common specimens.

6. Microbiology and the Role of the Medical Assistant
Microbiology – study of microorganisms (simple forms of life visible only through a microscope usually single celled)
Found everywhere
Cause infections
Mild
Severe

7. How Microorganisms Cause Disease
By using up nutrients or other materials needed by cells and tissues they invade
By damaging body cells by reproducing inside the cells
By making body cells targets of body’s own defenses
Resulting in:
Fever
Tiredness
Aches
Weakness
Skin reactions
Gastrointestinal upset
Transmitted from one person to another
by direct touching or by vectors,
droplets, or contaminated food or drink.

8. Classifications of Microorganisms
Subcellular – DNA or RNA surrounded by a protein coat
Prokaryotic – simple cell structure no nucleus or organelles
Eukaryotic – complex cell structure with nucleus and specialized organelles

9. Naming of Microorganisms
Types of microorganisms:
Viruses
Bacteria
Protozoans
Fungi
Multicellular parasites
Named by first word refers to genus (biologic classification between family and species) and second word refers to particular species
Staphylococcus aureus

10. Viruses Smallest known infectious agents
Cannot be seen by regular microscope
Consist of only nucleic acid surrounded by a protein coat
Causes:
Colds
Influenza
Croup
Hepatitis
Hepatitis Virus

11. Bacillus bacterial classification
Single-celled prokaryotic organisms
Reproduce quickly
Major cause of diseases
Many different types and ways to identify them
Rapid reproduction is why untreated infections can be dangerous
Bacillus bacterial classification

12. Bacteria Classification
Shape – coccus, bacillus, spirillum, virbrio
Ability to retain certain dyes
Ability to grow in presence or absence of air
Biochemical reactions
Spirillum bacterial classification

13. Protozoan Trichomonus vaginalis
Protozoans
Single celled eukaryotic organisms – larger than bacteria
Found in soil and water
Cause:
Malaria
Amebic dysentery
Trichomonus vaginalis
Protozoan Trichomonus vaginalis

14. Yeast a single-celled fungi
An eukaryotic organism – rigid cell wall
Grow mainly as single-celled
Reduce by budding
Yeasts
Molds
Cause superficial infections
Athlete’s foot
Ringworm
Thrush
Yeast a single-celled fungi

15. Parasites
Organism that lives on or in another and uses that organism to provide nourishment
Infections caused by parasites are called infestations
Worms
Insects -ticks

16. Apply Your Knowledge -Answer How is bacteria classified?
Shape – coccus, bacillus, spirillum, virbrio
Ability to retain certain dyes
Ability to grow in presence or absence of air
Biochemical reactions
-Answer
How is bacteria classified?

17. Diagnosing Infections
Step 1 – Examine the patients signs and symptoms
Step 2 – Obtain Specimens
Step 3 – Examine the Specimens Directly
Step 4 – Culture the Specimen
Step 5 – Determine the Culture’s Antibiotic Sensitivity
Step 6 – Treat the Patient as Ordered

18. Specimen Collection
If specimen is collected incorrectly, the organism will not grow in culture and then cannot be identified.
If a specimen contains contaminants that are identified as causing the infection, the patient may be treated incorrectly.

19. Specimen Collection Devices
Sterile swabs
Absorbent material on the tip
Collection and transporting systems
Contains a polyester swab and a small thin-walled vial of medium in a plastic sleeve

20. Throat Culture Specimens
Avoid touching any structures in the mouth
Get the specimen from the throat area only
Clinical medical assistants must know how to obtain a throat culture specimen correctly

21. Other Specimens
Urine
Obtain clean-catch midstream specimen to prevent contaminants
Sputum
Instruct patient to cough up mucus from the lungs
Wound
Use a swab
Stool
Use clean paper plate or waxed paper

22. Transporting Specimens
Many offices do not perform microbiologic testing.
You may send culture specimens to outside labs.
There are three main objectives.

23. Transporting Specimens (cont.)
Three main objectives:
Follow proper collection procedures and use correct device.
Maintain the samples in a state close to their original as possible.
Protect anyone who handles the specimen container from exposure to potentially infectious material.

24. Methods of Transportation
Regularly scheduled daily pickups by the lab
As needed pickup by the lab
Through the mail

25. Direct Examination of Specimens
Physician may examine specimens under the microscope to detect microorganisms.
Two types of procedures:
Wet mounts- permits quick identification
Potassium Hydroxide (KOH) mounts – suspects a fungal infection of the skin, nails, or hair.

26. Stained Specimens
Enables the doctor to differentiate between types of infections.
The medical assistant should be able to prepare a specimen slide and perform a Gram’s stain.

27. Culturing Specimens
You will need on-the-job training or additional courses to culture certain specimens.
More common to send these specimens to outside labs.
Culturing involves placing a sample of specimen on a culture medium.

28. Culturing Specimens (cont.)
Culture media – liquid, semisolid, or solid forms
Medium called – agar
Special culture units – used to perform rapid urine cultures (Unicult)

29. Culturing Specimens (cont.)
Inoculating a culture plate
Transferring some of the specimen onto the plate
Label the plate:
Patient’s name
Doctor’s name
Source of sample
Date and time of inoculation
Your initials

30. Culturing Specimens (cont.)
Streak the plate with the specimen swab for:
Qualitative analysis – type of pathogen
Quantitative analysis – number of pathogen present in the specimen
Incubating Culture plates – to allow bacteria to grow (incubator set at 35 to 370 C)
Allow to grow for 24 to 48 hours.

31. Interpreting Cultures
This step is performed by physicians, microbiologists, or technicians who have been properly trained.
They will look for:
Characteristics of colony growth
Relative number of colony growth
Changes in the media surrounding the colonies

32. Determining Antimicrobial Sensitivity
Taking a sample of the isolated pathogen and suspending it in a liquid medium and streaking it on a culture plate.
Small disks of filter paper with antimicrobial agents are placed on top.
Plate is incubated at 370 C for 24 hours.
The antimicrobial that inhibited microbial growth will be effective in treating the infection.

33. Quality Control in the Office
Ongoing system to evaluate the quality of medical care being provided.
Provides an objective means to define, monitor, and correct potential problems.
All media, staining solutions, and reagents should be evaluated frequently.
Equipment must also be in proper running order.

34. Impact of CLIA’ 88
All labs must incorporate the appropriate policies and procedures to comply with CLIA’ 88
Proper documentation of lab policies and procedures, materials, and lab personnel qualification and training.
Proficiency testing program monitors quality of laboratory’s test results

35. Apply Your Knowledge -Answer
Small disks of filter paper with antimicrobial agents are placed on top of the inoculated culture plate, and if the antimicrobial agents stop the growth of the pathogens, it will be effective in treatment of the infection.
-Answer
How are pathogens tested to see if they can be treated effectively by antimicrobial agents?

36. Medical Assistant Summary
Developing your clinical skills will be an asset to the office and will allow you to advance your career.
Quality control in the microbiology laboratory is an important factor in ensuring high-quality
medical care.

37. End of Chapter
End of Chapter