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Chapter 46 Introduction to Microbiology Medical Assisting

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1 Chapter 46 Introduction to Microbiology Medical Assisting
PowerPoint® presentation to accompany: Medical Assisting Third Edition Booth, Whicker, Wyman, Pugh, Thompson

2 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 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 Learning Outcomes (cont.)
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 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 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 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 Microbiology and the Role of the Medical Assistant (cont.)
Assists physician Obtains specimens Prepares specimens for direct examination Prepares specimens for transportation to reference laboratory If office has a POL, performs microbiologic procedures

9 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 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 Apply Your Knowledge Yippee! 2 for 2
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. How do microorganisms cause disease? Yippee! 2 for 2 ANSWER: Organisms cause disease by using nutrients needed by cells and tissues, damaging cells directly, or producing toxins.

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

14 Apply Your Knowledge Correct!
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 Correct!

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

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

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

19 Bacteria: Classification and Identification (cont.)
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

20 Bacteria: Classification and Identification (cont.)
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

21 Protozoan Trichomonas vaginalis
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 Yeast: a single-celled 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

23 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 Very Good! Apply Your Knowledge ANSWER: Matching:
___ Yeast or mold A. Virus ___ Tapeworm / lice B. Bacteria ___ Classified by shape C. Protozoan ___ Subcellular organism D. Fungus ___ May be aerobic or anaerobic E. Multicellular parasite ___ Smallest known organism ___ Found in soil and water Very Good! E B A B A C

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

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

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

28 Super! Apply Your Knowledge
What is the process for diagnosing an infection? ANSWER: There are six steps for diagnosis and treatment of an infection: Examine the patient 4. Culture the specimen Obtain specimen(s) 5. Determine sensitivity Examine specimen directly 6. Treat patient / appropriate antimicrobial Super!

29 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 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 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 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 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 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 Apply Your Knowledge Fantastic!
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. Fantastic!

36 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 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 Impressive! 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 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 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 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 Apply Your Knowledge What are the methods for preparing a slide for direct examination by the physician? ANSWER: They are wet mount and KOH mount. 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 Apply Your Knowledge 3 for 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. 3 for 3!

44 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 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 Culturing Specimens (cont.)
Incubating culture plates 35 to 37º 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 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 Apply Your Knowledge Bravo!
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. 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 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 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 Very Good! 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 In Summary Microorganisms are a major cause of disease
Medical assistant Collects specimens Processes or transports specimens Quality control – ensures quality medical care

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

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