Presentation on theme: "Chapter 46 Introduction to Microbiology Medical Assisting"— Presentation transcript:
1 Chapter 46 Introduction to Microbiology Medical Assisting PowerPoint® presentation to accompany:Medical AssistingThird EditionBooth, 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 natureDisplaced from their natural environmentMedical assistantIdentification of microorganismsProper collection techniquesTesting proceduresQuality control
7 Microbiology and the Role of the Medical Assistant Microbiology – study of microorganisms (simple forms of life visible only with a microscope)MicroorganismsNormal floraPathogenic
8 Microbiology and the Role of the Medical Assistant (cont.) Assists physicianObtains specimensPrepares specimens for direct examinationPrepares specimens for transportation to reference laboratoryIf office has a POL, performs microbiologic procedures
9 How Microorganisms Cause Disease Cause disease in variety of waysUse nutrients needed by cells and tissuesDamage cells directlyProduce toxinsMay remain localized or become systemicTransmissionDirect contactIndirect contact
10 How Microorganisms Cause Disease (cont.) Localized symptomsSwellingPainWarmthRednessGeneralized symptomsFeverTirednessAchesWeaknessNormal floraProvides a barrierCan 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 2ANSWER: 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 structureSubcellular – DNA or RNA surrounded by a protein coat – virusesProkaryotic – simple cell structure with no nucleus or organelles – bacteriaEukaryotic – complex cell structure with nucleus and specialized organelles – protozoans, fungi, parasites
13 Classification and Naming of Microorganisms (cont.) Standardized namingGenusCategory of biologic classificationExample – StaphylococcusSpecies of organismRepresents a distinct type of microorganismsExamples – 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 – virusesProkaryotic organisms have a simple cell structure with no nucleus or organelles – bacteriaEukaryotic have a complex cell structure with nucleus and specialized organelles – protozoans, fungi, parasitesCorrect!
15 Viruses Smallest known infectious agents Subcellular microorganism Have only nucleic acid surrounded by a protein coatMust live and grow in living cells of other organismsHepatitis virus
16 Viruses (cont.) Illnesses caused by viruses ColdsInfluenzaCroupHepatitisWartsVaccines are available for many virusesAIDSMumpsRubellaMeaslesHerpes
17 Bacillus bacterial classification Single-celled prokaryotic organismsReproduce rapidlyClassificationShapeAbility to retain dyesAbility to grow with / without airBiochemical reactionsBacillus bacterial classification
18 Bacteria: Classification and Identification ShapeCoccus – spherical, round, or ovoidBacillus – rod-shapedSpirillum – spiral-shapedVirbrio – comma-shapedSpirillum bacterial classification
19 Bacteria: Classification and Identification (cont.) Ability to retain certain dyesGram’s stainAcid-fast stainAbility to grow in presence or absence of airAerobes – grow best in the presence of oxygenAnaerobes – grow best in the absence of oxygenBiochemical reactions
20 Bacteria: Classification and Identification (cont.) Special groupsMycobacteria – bacilli with a cell wall that differs from most bacteriaRickettsiaeVery smallLive and grow within other living organisms such as mites and ticksChlamydiaeCell wall structure differs from other bacteriaLive and grow within other living cellsMycoplasmas – completely lack the rigid cell wall
21 Protozoan Trichomonas vaginalis ProtozoansSingle-celled eukaryotic organisms, larger than bacteriaFound in soil and waterIllnessesMalariaAmebic dysenteryTrichomoniasis vaginitisLeading cause of death in developing countriesProtozoan Trichomonas vaginalis
22 Yeast: a single-celled fungi Eukaryotic organisms with rigid cell wallYeastsSingle-celledReproduce by buddingMoldsLarge, fuzzy, multicelled organismsProduce sporesSuperficial infectionsAthlete’s footRingwormThrushCan cause systemic infections
23 Multicellular Parasites Organisms that live on or in another organism and use it for nourishmentParasitic wormsUsually due to poor sanitationRoundwormsFlatwormsTapewormsParasitic insectsBite or burrow under the skinMosquitoesTicksLicemites
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 waterVery Good!EBABAC
25 How Infections Are Diagnosed Steps to diagnosis and treatmentExamine the patientPresumptive diagnosisMay or may not need additional testsObtain specimen(s)Label properlyInclude presumptive diagnosis
26 How Infections Are Diagnosed (cont.) Examine specimen directlyWet mountSmearCulture specimenCulture medium – contains nutrientsExamine culture visually and microscopically
27 How Infections Are Diagnosed (cont.) Determine sensitivity to antibioticsTreat the patient as orderedAntimicrobial – 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 specimenObtain specimen(s) 5. Determine sensitivityExamine specimen directly 6. Treat patient / appropriate antimicrobialSuper!
29 Specimen Collection Must be collected correctly If not, may not grow in cultureContaminants may be mistakenly identifiedPatient may receive incorrect or harmful therapy
30 Specimen Collection (cont.) DevicesUse appropriate collection device or specimen containerSterile swabs – absorbent material on the tipCollection and transporting systemsSterile, self-containedTransport mediumAerobic or anaerobic
31 Specimen Collection: Guidelines Avoid causing harm, discomfort, or undue embarrassmentCollect from appropriate siteObtain specimen at correct timeUse appropriate devicesObtain sufficient quantity of specimenObtain specimen prior to the start of antimicrobial therapyLabel correctly
32 Specimen Collection (cont.) Throat culture specimensSwab back of throat in the area of the tonsilsAvoid touching any structures in the mouthPrepare culture plate or prepare correctly for transport to laboratory
33 Specimen Collection (cont.) Urine specimenClean-catch midstream to minimize contaminantsProcess within 60 minutes or refrigerateSputum specimenSpecimen from lungsAvoid contaminating specimen with saliva
34 Specimen Collection (cont.) Wound specimenSwab wound or lesionDo not touch outside of woundStool SpecimensTechnique variesBacterial infectionProtozoal or parasitic infectionInstruct 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 labThree main objectivesFollow proper collection procedures and proper collection devicePrevent deterioration of specimenProtect anyone handling specimen
37 Transporting Specimens to an Outside Laboratory (cont.) Regularly scheduled daily pickups by the labMost reliableAs-needed pickup by the labThrough the mailFollow U.S. Public Health Service regulationsEtiologic 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 immediatelyWet mountsNaCl mixed with specimen of glass slidePresence of pathogen and movement of microorganismPotassium hydroxide (KOH) mountsUsed if a fungal infection of the skin, nails, or hair is suspectedKOH dissolves keratin that can mask presence of a fungus
40 Preparation and Examination of Stained Specimens Quick, tentative diagnosisDifferentiation between types of infectionsGram’s stainModerate- complexity testBacteria either retain or lose purple colorGram-positive bacteriaGram-negative bacteria
41 Culturing Specimens in the Medical Office More common to send specimens for culture to outside labsCulturing involves placing a sample of specimen on a culture mediumMedium – nutrientsPlace in incubator for growth – colony develops as microorganism multiplies
42 Apply Your KnowledgeWhat 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 mediaLiquid, semisolid, or solid formsContains agarSelective or nonselectiveSpecial culture unitsRapid urine culture – UricultAlso available for throat, vaginal, and blood specimens
45 Culturing Specimens (cont.) Inoculating a culture plateTransfer some of the specimen onto a culture plateLabel the plate correctlyQualitative analysis – determination of type of pathogenQuantitative analysis – number of bacteria present in sample
46 Culturing Specimens (cont.) Incubating culture plates35 to 37º C for 24 to 78 hoursAgar side upInterpreting culturesRequires skill and practiceCharacteristics of coloniesRelative numberChanges to media around colonies
47 Determining Antimicrobial Sensitivity An outside lab reportsSensitive – no growthIntermediate – little growthResistant – overgrownProcedureFilter paper containing antimicrobial agents placed on inoculated agar plateIncubated for 24 hoursEvaluate 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 providedObjective means to define, monitor, and correct potential problemsRoutine evaluationAll media, staining solutions, and reagentsEquipment
50 Quality Control: Impact of CLIA ’88 Appropriate policies and proceduresProper documentationLab policies and proceduresMaterialsPersonnel qualifications and trainingParticipation 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 assistantCollects specimensProcesses or transports specimensQuality control – ensures quality medical care
53 End of ChapterEnd of Chapter 46Each organism's environment, for the most part, consists of other organisms.~ Kevin Kelly
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