Diagnostic microbiology


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Diagnostic Microbiology Organization

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Diagnostic microbiology

  2. 2. Challenges in Diagnostic Laboratories• The work environment has changed with the development of new technology. Laboratories have always seen the need for change and development, there has been increased pressure to improve performance, tighten margins, improve quality and reduce costsDR.T.V.RAO MD 10/12/2012 2
  3. 3. Medical Laboratory Managers• Each laboratory must have a strategic plan that describes its long-term goals, such as a move toward more automation or molecular diagnostic techniques.• Each employee’s role should be clearly defined, and written job descriptions should be provided so personnel know what they are expected to do. Therefore, it is a not an easy task for a manger to strike a balance among the clinical laboratory regulations, fiscal responsibility, and employee competence and morale to maintain the overall quality of patient care.DR.T.V.RAO MD 10/12/2012 3
  4. 4. THE LABORATORIES SHOULD FACTION FROM SENSE TO COMMON SENSE• It is appropriate to remember that the two most important components of management are• Common sense• Open communication with laboratory staffDR.T.V.RAO MD 10/12/2012 4
  5. 5. MICROBIOLOGY LABORATORY Clinical Microbiology comprises essentially seven sections. • Aerobic and anaerobic bacteriology • Mycology • Mycobacteriology (also called Acid-fast Bacteriology, AFB) • Parasitology • Virology • Serology • Molecular diagnostics (PCR & DNA probe technology) • :DR.T.V.RAO MD 10/12/2012 5
  6. 6. PLAN FOR THE DIVISION OF MICROBIOLOGYSample Receiving & ProcessingSectionSamples brought to the clinicalmicrobiology are at first received bythis section. Here sample are receivedand the samples are processedaccording to the nature of the sample.• Urinalysis Section In this section detailed report of urine samples including physical, chemical, microscopic examination is be prepared.DR.T.V.RAO MD 10/12/2012 6
  7. 7. DIVISION OF PARASITOLOGY • Parasitology Section Parasitology section deals with intestinal parasites. Samples of faeces are examined here for the presence of any intestinal parasite. Slides are prepared here inside a safety cabinet.DR.T.V.RAO MD 10/12/2012 7
  8. 8. BACTERIOLOGY CULTURES MAIN PART OF LABORATORY SERVICES• Nose, Throat, Sputum and Urogenital Cultures and Sensitivity Section Here cultures of respiratory tract and genital tract infections are prepared.• Blood cultures, Wounds Culture and Sensitivity Section Culture of wound swab, pus, aspirates, body fluids including CSF are the responsibility of this section.DR.T.V.RAO MD 10/12/2012 8
  9. 9. BACTERIOLOGICAL CULTURES IS THE MAJOR GRATIFYING WORK • Urine Culture & Sensitivity Section Different types of urine culture performed here including mid stream urine and catheter samples of urine. Each sample is processed and evaluated accordingly. • Blood Culture and Sensitivity Section In this section culturing of blood samples is carried out. Nowadays, this section is equipped by machines such as Bactec 9240, flourometric instruments. Each instrument is capable of running 240 samples at a time.DR.T.V.RAO MD 10/12/2012 9
  10. 10. SEROLOGY SECTION• Serology Section In serology section immunological and serological tests are performed by different techniques like Latex agglutination, haemagglutination and antibody absorption.DR.T.V.RAO MD 10/12/2012 10
  11. 11. MYCOBACTERIOLOGY • Mycobacteriology Culture & Sensitivity Section In this section all TB smear, culture and sensitivity performed in two Biosafety II and III cabinets to avoid risk of infectionDR.T.V.RAO MD 10/12/2012 11
  12. 12. MYCOLOGY LABORATORY SERVICES AN EMERGING NEED• Mycology Culture Section Requests for fungus smear and culture processed here in a bio safety II cabinet to avoid infection from fungal spore.• Regardless of the organisation of a Microbiology Laboratory, the main aim is providing the client (the physician) with accurate and reliable results to assist the process of clinical treatment.DR.T.V.RAO MD 10/12/2012 12
  13. 13. QUALITY CONTROL IN MICROBIOLOGY LABORATORY • Quality Control Section In this section quality control of water, food products and environment is performed with the help of different media and colonyDR.T.V.RAO MD counters.10/12/2012 13
  14. 14. MANAGING THE SAMPLE: TECHNICAL• Macroscopic evaluation• Split sample for different laboratory disciplines• Two possible approaches: • perform only those tests requested by sender • perform diagnostics for syndromes/clinical description (laboratory initiative)• Storage of samples • refrigerator or freezer DR.T.V.RAO MD 10/12/2012 14
  15. 15. DIRECT METHODS1. Macroscopic evaluation2. Direct microscopy3. Electron microscopy No propagation4. Staining required5. Rapid tests6. Molecular methods7. Propagate the agent DR.T.V.RAO MD 10/12/2012 15
  16. 16. MACROSCOPIC EVALUATION AN EXAMPLE• Consistency • rice water stools for Cholera• Blood• Visible parasites • Helminths • segmentsDR.T.V.RAO MD 10/12/2012 16
  17. 17. DIRECT MICROSCOPYWet mount technique Observations • hanging drop • white blood cellsDark background microscope (denotes invasion) • fragile organisms • red blood cells (e.g. spirochetes) • parasitesViability maintained • protozoa • mobility may be observed • Helminths • eggs • moving bacteria DR.T.V.RAO MD 10/12/2012 17
  18. 18. STAINING• A specific staining • Gram staining• Specific staining with chemicals • Ziehl Neelsen staining (Mycobacteria) • Modified Ziehl Neelsen staining (Cryptosporidium)• Specific staining with labelled antibodies • Immunofluorescence - used when gram stain cannot help in diagnosis (e.g. Legionella too small to be visible in a Gram stain) DR.T.V.RAO MD 10/12/2012 18
  19. 19. RAPID TESTS• Goals • bacterial, viral or parasite antigen (surface antigen, soluble antigen) • toxin in biological fluids (e.g. cerebrospinal fluid, blood, urine)• Main techniques • direct agglutination: slides, cards • latex agglutination: slides, cards • immuno-chromatography: dipsticks DR.T.V.RAO MD 10/12/2012 19
  20. 20. . DIRECT METHODS - PROPAGATION REQUIRED• Bacteriology and mycology • most agents can be propagated on culture media• Virology • most agents can be propagated on cells• Parasitology • monocellular organisms can be propagated in culture media DR.T.V.RAO MD 10/12/2012 20
  21. 21. PERSONNEL• The following directorial functions are :1- interpretation , correlation , and communication of lab data2- interaction with physicians and/or medical staff , patient , administration .3- monitoring of standard of performance , QC , QI.4- provision of education programs , planning , research.5- ensuring sufficient personnel with adequate documented training and experience to meet the needs of the lab .6- he/she must be decision-maker in the selection of all lab equipments and supplies . DR.T.V.RAO MD 10/12/2012 21
  22. 22. PROPAGATION: ADVANTAGES/DISADVANTAGES• Advantages • allows anti-microbial susceptibility testing • allows typing of the micro-organism • allows storage of the strain• Disadvantages • depends upon the viability/condition of the agent • takes time DR.T.V.RAO MD 10/12/2012 22
  23. 23. DETECTING ANTIBODIES• Precipitation• Agglutination• Haemagglutination and haemagglutination inhibition• Viral neutralization test• Radio-immunoassays• ELISA• Immunofluorescence• Immmunoblotting• Immunochromatographic DR.T.V.RAO MD 10/12/2012 23
  24. 24. ANTIBODY DETECTION: ADVANTAGES/DISADVANTAGES• Advantages • inexpensive • easy to perform • allows identification of • IgM (acute infection) • IgG (past infection)• Disadvantages • delayed response (false negative results during sero-conversion window) • time of infection not always clear DR.T.V.RAO MD 10/12/2012 24
  25. 25. STANDARDS AND CHECKLISTS• Purposes: • Standards are the broad principles the laboratory must meet in order to achieve accreditation • Checklists provide detailed requirements that inspectors use to determine whether laboratories meet the StandardsDR.T.V.RAO MD 10/12/2012 25
  26. 26. LABORATORY INSPECTIONS: MAINTAINING BALANCE Education Quality Regulatory Improvement ComplianceDR.T.V.RAO MD 10/12/2012 26
  27. 27. THE STANDARDS FOR LABORATORY ACCREDITATION• Standard I Director / Head of the Divison• Standard II Physical Facilities & Safety• Standard III Quality Control and Performance Improvement• Standard IV Inspection Requirements DR.T.V.RAO MD 10/12/2012 27
  28. 28. CHECKLISTS• Guide the inspection by assisting with the interpretation of desired Standards• Provide guidelines for development of laboratory policies, procedures and processes• Help ensure accurate, reliable test results• Ensure a focus on patient safety DR.T.V.RAO MD 10/12/2012 28
  29. 29. Quality control and Quality improvement• The QC / QI program should be clearly defined and well- organized.• The QI program must provide the system design and evaluation of proper patient identification and preparation ; specimen collection ; preservation ; transportation ; storage before testing ; processing ; and accurate results reporting.• This system must ensure optimum patient specimen and integrity of the result throughout the pre-analytical , analytical , and post-analytical process.DR.T.V.RAO MD 10/12/2012 29
  30. 30. QI / QA “SUPERVISION Judgment of the acceptability of QC data must be made at least monthly by the lab director . Because of many variables , the CAP makes no specific recommendations on the frequency of any additional assessment / review of QC data. There must be evidence of active review of records of instrument function , temp , and maintenance , for all routine procedures on all shifts. DR.T.V.RAO MD 10/12/2012 30
  31. 31. QI / QA “SUPERVISION”• The lab must have documented system in operation to detect and correct significant clerical and analytical errors.• One common method is review of results by a qualified person before release from the lab , but there is no requirement for supervisory review of all reported data.• The selective use of delta checks also may be useful in detecting clerical errors in consecutive samples from the same patient.• In computerized lab , there should be automatic alarm for improbable results. DR.T.V.RAO MD 10/12/2012 31
  32. 32. EFFECTS OF PRE-ANALYTICAL VARIABLES ON THE QUALITY OF LABORATORY TESTING• Modern laboratories around the world are now enjoying the benefit of decades of development in technology• “State of the Art" instrumentation are common in most laboratories• Walkway, high throughput analyzers are employed for routine and specialized testingDR.T.V.RAO MD 10/12/2012 32
  33. 33. • Programme Created by Dr.T.V.Rao MD for Medical Microbiologists • Email • doctortvrao@gmail.comDR.T.V.RAO MD 10/12/2012 33